Anatomy FINAL1.docx

Week 1 The Cardiovascular System Anatomy Overview: The cardiovascular system consists of the heart, blood, and blood vessels. For the blood to reach each cell of the body it must be pumped continuously. The left side of the heart's pumps blood through 120000km of blood vessels and the ride side of the heart pumps through the lungs. At rest the heart pumps 5L of blood/minute and during exercise the heart pumps 25L of blood/minute. The heart rests in the diaphragm near the midline of the thoracic cavity and lies in the mediastinum (2/3 of the heart lies to the left) COVERINGS OF THE HEART Pericardium: this is the membrane that surrounds and protects the heart its function is to confine the heart to the mediastinum and allows for movement Fibrous Pericardium: it is a superficial, tough, inelastic, dense irregular CT. The open end is fused to CT of blood vessels entering/leaving the heart. It helps prevent over stretch and is partial fusion with central tendon of the diaphragm Serous pericardium: it is the thinner delicate layers there is a parietal layer and a visceral layer which is called the epicardium. Pericardial Fluid: it is a thin film of lubricating fluid that reduces friction and the space containing fluid called the pericardial cavity LAYERS OF THE HEART Epicardium: made of mesothelium beneath is a variable layer of fibroelastic and adipose tissue. It contains blood vessels, lymphatics, and vessels to supply the myocardium Myocardium: thick muscle layer and fibers in bundles that swirl diagonally Endocardium: thin layer of endothelium overlying layer of CT and provides smooth lining for heart chambers it also covers the heart valves CHAMBERS OF THE HEART The heart is divided into 4 chambers a left and right chamber are separated by an extension of the heart wall called the septum Atria (atrium): these are the upper chambers separated by interatrial septum and the flaps protruding from the atrium are called auricles. Ventricles: (pumping chambers) these are the lower chambers seperated by the interventricular septum VALVES OF THE HEART Atrioventricular (AV) Valves: between atria and ventricles they also prevent the blood floe back and pointed flaps are called cusps. Tricuspid: right AV valve has 3 cusps Bicuspid: (mitral) left AV valves has 2 cusps To prevent damage to AV valves tethered to the walls of ventricles by heart strings called chordae tendinea. The valves are attached to papillary muscles and muscles pull on AV valves via chordae tendinea Pulmonary valves: entrance to pulmonary artery Aortic valves: entrance to aorta BLOOD SUPPLY OF THE HEART TISSUE: Coronary arteries: myocardial cells receive blood from arteries that lie behind the aortic valve (left and right) Blood flows to these arteries during ventricular relaxation. Both ventricles receive blood from branches of left and right coronary arteries. Each atrium receives a small branch of the corresponding artery and a few anastomoses between larger branches. Coronary veins: cardiac veins follow a course that parallels coronary arteries. After passing through capillary networks of myocardium, blood enters a series of cardiac veins. And drains into the right atrium via the coronary sinus which is a small collection of veins from the right ventricle drain directly into the right atrium. NERVE SUPPLY OF THE HEART Myocardium is autorhythmic and rhyme can be modified by afferent (sensory) nerves Cardiac plexus: (near arch of the aorta) has a sympathetic (accelerator) and the Vagus CN X which is the inhibitory depressor Most fibers end at the sinoatrial (SA) node Some fibers end at the atrioventricular (AV) node and in the atrial myocardium CONDUCTION SYSTEM OF THE HEART: specialized myocardial fibers (myoneural) that provides rapid electrical conduction along heart tissue WEEK 2 THE CARDIOVASCULAR SYSTEM ANATOMY: BLOOD VESSELS Blood flows through the heart through many types of vessels back to the heart as follows: Arteries Arterioles Capillaries Venules Veins Arteries: carry oxygenated blood away from heart Veins: carry deoxygenated blood back to the heart Capillary beds: sites of exchange between tissues and blood ARTERIES: Carry blood away from the heart. All arteries except pulmonary arteries carry oxygenated blood Elastic arteries: these are the largest and stretch without injury they also accommodate surge of blood Muscular (distributing) arteries: smaller in diameter thick and muscular layer Arterioles: (resistance vessels): smallest arteries they are regulating blood flow to end organs and the arterioles increase resistance to blood flow and regulates blood pressure Metarterioles: short connecting vessels between true arteriole and capillaries they are encircled by precapillary sphincters at proximal end and at the distal end there care thoroughfare channel which is free of precapillary sphincters CAPILLARIES: Primary exchange vessels: these are microscopic vessels that carry blood from arterioles to venules they are not evenly distributed, and cartilage and epithelium are avascular Continuous Capillaries: openings between endothelial cells called intercellular clefts found in skeletal muscle, lung, and CT Fenestrated capillaries: these are intercellular clefts between endothelial cells they have small holes or fenestrations in plasma membrane and facilitates exchange functions (ex. Kidneys) Sinusoids: large lumen and tortuous course, very porous, permit migration of cells, found in bone marrow and liver VEINS: Vessels that carry blood toward the heart. Venules: From the capillary blood enters a series of vessels Veins: blood enters into progressively larger channels (capacitance vessels) Accommodate varying amounts of blood with little change in blood pressure Peripheral veins have a greater number of valves Varicose veins: incompetence in valves blood tends to pool rather than continue toward heart Heart arteries and capillaries carry 30-35% of blood volume, and the venous system carries 60-65% STRUCTURE OF BLOOD VESSELS Walls consists of 3 layers Tunica externa: outer layer is the flexible fibrous CT and found in arteries and veins Tunica media: middle smooth muscle found in arteries and veins Tunica intima: inner epithelial and connective tissue found in all blood vessels and only layer present in capillaries Systemic circulation: this is the blood flow from left ventricle through blood vessels to all parts of body back to the right atrium Pulmonary circulation: venous blood moves from right atrium to right ventricle to pulmonary trunk/artery to lung arterioles and capillaries. Gases are exchanges. Oxygenated blood returns to left atrium and blood enters the left ventricle. Pulmonary circuit: pulmonary trunk, pulmonary arteries, alveolar capillaries, venules, and pulmonary veins SYSTEMIC CIRCULATION: ARTERIES Arterieal system: vessels originate fron aorta extending from the left ventricle and most arteries are paired and lie deep to skin Main arteries: give off branches continue to branch and rebranch these form arterioles then capillaries End Arteries: eventually diverge into capillaries and supply areas or organs of the body Arterial anastomoses: arteries that open unto other branches of same or other arteries. Incidence of arterial anastomoses increases as distance from heart increases Arteriovenous anastomoses: shunts Branches of the aorta: largest artery in the body with 4 major divisions Arteries of upper limbs: derived entriely from subclavian artery Arteries of head and neck: primarily from r. and l. common carotid some contributions from subclavian arteries Arteries of the thorax: derived from branches of subclavian arteries and descending thoracic aorta Arteries of the abdomen: derived from the abdominal aorta – branches supply abdominal viscera SYSTEMIC CIRCULATION VEINS Extensions of capillaries, size increases as vessels unite, dural sinuses, veins anastomose, generally 2 sets a deep and superficial Superior vena cava: blood form head, neck, upper extremities, and thoracic cavity Inferior vena cava: blood from lower extremities, abdomen Veins of the upper limb: consists of a superficial system and a deep system Veins of the head and neck: 3 main veins and dural sinuses Veins of the thorax and abdomen: anterior: drain into brachiocephalic and external iliac veins. The posterior is drained by the azygos system Pelvic organs are drained by internal iliac vein Several veins of the abdomiopelvic cavity drain directly into the inferior vena cava FETAL CIRCULATION: Special circulatory requirements Derives its oxygen and nutrients and eliminates wastes through the birthing parent blood supply by way of the placenta Umbilical arteries: carry blood from fetus to placenta Umbilical vein: carries blood from the placenta and drains into the ductus venosus Oxygenated blood in umbilical vein bypasses liver via the ductus venosus and sumps into inferior vena cava Oxygen right blood bypasses lungs by traveling to left heart through foramen ovale and a one-way valve to prevent backflow Blood remaining in right heart is diverted into left sided circulation by passing through the ductus arteriosus before returning to placenta via umbilical arteries NEONATAL CIRCULATION WEEK 3 CARDIOVASCULAR SYSTEM HEMODYNAMICS Intro: the cardiovascular system plays a vital role in maintaining homeostasis. It depends on the continuous controlled movement of blood through the capillaries, it permeates every tissue and reaches every cell in the body. Hemodynamics: it is a collection of mechanisms that influence the dynamic circulation of blood. Circulation is the only means by which cells receive materials. Circulation control mechanisms must accomplish 2 functions: 1. maintain circulation and 2. vary volume and distribution of the blood circulated THE HEART AS A PUMP Permit rapid conduction of electrical impulses through heart not contractile fibers. SINOATRIAL (SA) NODE: Initiates each heartbeat sets the pace. It is located in the right atrial wall and has specialized pacemaker cells (myoneural) in node possess an intrinsic rhythm AUTORHYTHMICITY: During development approximately 1 % of all muscle cells of the heart form a network called the conduction system. Specialized groups of myocytes are unusual in that they have the ability to spontaneously depolarize Rhythmical electrical activity cells produce is called autorhythmic Because heart muscle is autorhythmic, it does not rely on CNS to sustain a heartbeat Autorhythmic cells spontaneously depolarize at a given rate When cells reach threshold an action potential starts and all cells in that area of the heart also depolarize. The spread of ions through gap junctions of intercalated discs allow AP to pass from cell to cell CARDIAC CONDUCTION Spontaneous depolarization of autorhythmic fibers in SA node firing every 0.8 seconds (=75 AP/min) HEART RATE Resting heart rate varies with age, general health, physical conditioning Normal is 60-100bpm Bradycardia: heart rate is slower than normal (<60bpm) Tachycardia: heart rate is faster than norma (>100bpm) SEQUENCE OF CARDIAC CONDUCTION: After being generate by the SA node, each AP travels through muscle fibers of both atria which begin to contract As AP enters the AV node its conduction slows allowing complete contraction of both atrial chambers After AV node conduction velocity increases as impulse is relayed through AV bundle/branches (left and right) into the ventricles. Right and left branches of bundle fibers and subendocardial branches (Purkinje fibers) conduct impulses throughout muscles of both ventricles stimulating them to contract almost simultaneously. COORDINATING CONTRACTIONS: Bands of muscles wind around the heart and work as a unit called functional syncytium allows the top and bottom parts to contract in their own way. Atrial syncytium contracts as a single unit to force blood down into ventricles Ventricular syncytium starts contraction at apex squeezing blood upward to exit outflow tracts FIBRILLATION OF THE HEART Cardiac muscles acts as if there are thousands of pacemakers Each make a small portion of the heart contract rapidly and independently of all other areas Defibrillation is needed or death will occur in minutes Causes simultaneous depolarization ANS INNERVATION: Heart does have sympathetic and parasympathetic innervation It regulates changes in blood pressure, flow, and volume to maintain cardiac ouput The cardioaccelerator center is found in the medulla and baroreceptors relay information about blood pressure and flow In response to the sympathetic nerves present throughout atria (SA node) and ventricles the result is an increase in heart rate, strength of myocardiac contraction, and blood flow out of the heart. The medullar also contains cell bodies of neurons that make up the cardioinhibitory center where sensory information coming from baroreceptors goes to this area. As well as when stimulated parasympathetic fibers in CN X vagus release Ach and this decreases heart rate CARDIAC MUSCLE CELL CONTRACTIONS: AP initiated by SA node travels through conduction system to excite contractile muscle fibers Contractile fibers have a stable RMP of –90mV and AP propagates by opening/closing Na and K channels CARDIAC MUSCLE CELL CONTRACTION STAGES: RAPID DEPOLARIZATION: At threshold, voltage gated sodium channels open Influx of sodium ions Channels are called fast sodium cannels PLATEAU Membrane potential remains near 0mV 2 opposing factors maintain: 1. fast Na channels close as membrane potential approaches 30 mV and 2. fast K channels open and K rushes out causing membrane to repolarize, and 3 voltage gated Ca channels open causing and influx of Ca and this clows calcium channels REPOLARIZATION: Slow Ca channels close Slow K channels open K out rapid repolarization Restores RMP (-90mV) Skeletal muscles AP = relatively brief, contraction period = short and tetanic contractions = can occur Cardiac muscles AP = long, contraction period = long and tetanic contractions cannot occur Cardiac muscle cells: the refractory period lasts longer than contraction and another contraction cannot begin until relaxation is underway, and tetanus cannot occur THE ELECTROCARDIOGRAM: ECG/EKG: is a recording of the electrical changes on a surface of the body resulting from depolarization and repolarization of the myocardium Abnormal EKGs show problems withing conduction pathways if heart is enlarged or if damaged Depolarization of atrial contractile fibers produce P wave Atrial systole contraction (plateau) Depolarization of ventricular contractile fibers produces QRS complex Ventricular Systole contractions (plateau) Repolarization of ventricular contractile fibers produces T wave Ventricular diastole (relaxation) PRIMARY PRINCIPLE CIRCULATION Any fluid flows because of a pressure gradient Blood circulates from left ventricle to right atrium of heart because a blood pressure gradient exists between these 2 structures Perfusion pressure: pressure gradient needed to maintain blood flow through a local tissue As blood is pumped from the left ventricle the systolic and diastolic pressures in the arterial system fall By the time the blood returns to the right atrium via the vena cava and there is a progressive fall in pressure to nearly 0 mmHg CARDIAC OUTPUT Primary determinant of arterial blood pressure is the volume of blood in the arteries An increase in blood volume and increase in blood pressure Cardiac output: volume of blood pumped out of the hear per unit of time (volume/min) Stroke volume: volume of blood pumped/heartbeat Heart rate and stroke volume determine cardiac output ao anything that changes either heart rate or stroke volume also tends to change cardiac output arterial blood volume and pressure in the same direction FACTORS AFFECTING STROKE VOLUME: Influences on end-diastolic volume (EDV): blood in ventricle at end of ventricular diastole Venus return: amount of venous blood returned to the right atrium Filing time: duration of ventricular diastole, slowing heart rate increases EDV and increasing heart rate decreases EDV Preload: amount of myocardial stretching, and greater EDV = larger preload = greater stroke volume The longer and more stretched heart fibers at beginning of contraction the stronger the contraction and contraction matches pumping load and each stroke adjusts to input Influences in end systolic volume: blood in ventricle at end of ventricular systole Contractility: force produced during contraction at given preload and varies with autonomic stimulation hormones and drugs Afterload: forces that oppose ventricular ejection, the greater afterload=decreased stroke volume, and increased by any factor that restricts arterial blood flow ex. Vasoconstriction FACTORS THAT AFFECT HEART RATE SA node initiates each heartbeat and factors that can change the rate Cardiac Pressoreflexes: Receptors sensitive to pressure changes located in 2 places: the carotid and aortic baroreceptors Relay to autonomic cardiac control center Parasympathetic and sympathetic outflow to control blood pressure Carotid sinus reflex: Sensory information from baroreceptors in carotid sinus via CN IX to cardiac control center in medulla Aortic reflex: Sensory information from baroreceptors (aortic arch) via aortic nerve and vagus nerve (CN X) to CCC in medulla PRESSURE, FLOW AND RESISTANCE Cardiovascular homeostasis is mainly dependent on blood flow Ohms law BP=Flow x Resistance To meet physiological demands, we can increase blood flow by increasing blood pressure and decreasing vascular resistance ARTERIAL BLOOD PRESSURE Peripheral resistance: resistance to blood flow imposed by force of friction between blood and walls of its vessels FACTORS THAT INFLUENCE PERIPHERAL RESISTANCE Blood viscosity: thickness of blood as a fluid Viscosity changes very little High plasma protein, high hematocrit, anemia, hemorrhage Diameter of arterioles: Small changes in blood vessel diameter cause large changes in resistance Vasomotor mechanism VASOMOTOR MECHANISM Muscle in wall of arteriole constrict or dilate changing diameter HOW DOES RESISTANCE INFLUENCE BLOOD PRESSURE Arterial BP varies directly with peripheral resistance Friction caused by viscosity and small diameter Wall of arterioles allow them to constrict/dilate and change amount of resistance to blood flow Wall of arterial pressure by controlling amount of blood that runs from arteries to arterioles = arteriole run off Increased resistance = less arterial run off = more blood left in arteries = lead to higher arterial pressure Locally (one organ) or total peripheral resistance VASOMOTOR PRESSOREFLEXES Sudden increase in arterial BP and stimulates aortic and carotid baroreceptors and CCC inhibits vasocontraction centers Sudden decrease in arterial blood pressure stimulates aortic and carotid baroreceptors and CC stimulates vasoconstriction center HYPERTENSION: Persistent high blood pressure Causes thickening of tunica media Accelerates atherosclerosis, CAD, increases system vascular resistance. Lifestyle changes: Treatment: diuretics, ACE inhibitors, beta-blockers, vasodilators, and Ca channel blockers HYPOTENSION: Any blood pressure too low to allow sufficient blood flow to meet metabolic demands Ventricles have to work harder to eject blood Hypotension leading to hypo-perfusion of critical organs results in shock VASOMOTOES CHEMOREFLEXES: Chemoreceptors in aortic and carotid bodies sensitive to hypercapnia, hypoxia, and a decrease in blood pH THE LYMPHATICS SYSTEM AND IMMUNITY WEEK 4 Lymphocytes: primary cells of the lymphoid system COMPONENTS: Vessels Fluids Lymphocytes Lymphoid tissues and organs FUNCTION: Production, maintenance, distribution of lymphocytes stored in lymphoid organs Return of fluid and solutes Drain excess IF to maintain blood volume Distribution of hormones, nutrients and wastes Substances unable to enter blood stream directly Lipids absorbed by digestive tract LYMPH Clear-milk extracellular fluid (plasma – IF – lymphatic fluid) Flow of lymph: from periphery toward central body IF – lymphatic capillaries – lymphatic vessels – regional lymph nodes LYMPHATIC VESSELS CAPILLARIES: Smallest vessel called capillaries Greater permeability to absorb proteins and lipids (lacteals) Unique one-way structure with anchoring filaments Has a blind end Capillaries converge to vessels and vessels converge as lymph flows through nodes TRUNKS AND DUCTS: Lymphatics leaving nodes unite to form principle lymphatic trunk: Lumbar: Lower limbs, wall and viscera of pelvis, kidneys, adrenal glands, abdominal walls Intestinal: Stomach, intestines, pancreas, spleen, part of the liver Broncho-mediastinal: Thoracic wall, lung, heart Subclavian: upper limbs Jugular: Head and neck The trunks unite into 2 main ducts: Thoracic duct (left the big one): Left side of head, neck, chest, left upper arm, and entire body inferior to ribs The thoracic duct is the main return of venous blood Lymphatic duct (right small one) Right side of head, neck, chest, and right upper limb Lymphedema: blockage of lymphatic drainage from limb causes limb to swell due to accumulation of interstitial fluid FORMATION AND FLOW OF LYMPH Water and solutes continually filter out of capillary into IF More fluid filters out than returns Excess fluid drains into lymphatic vessels Lymphokinesis is the flow of lymph Lymph flows against gravity FORMATION OF LYMPH Fluids from systemic and pulmonary capillaries leave blood stream and enter interstitial space IF exchanges materials with surrounding tissues Less fluid returned to blood capillary IF pressure increases IF flows into lymphatic capillary Lymph carries through lymph nodes to ducts to subclavian vain returned to systemic blood plasma SKELETAL MUSCLE PUMP (flow of lymph) Milking action Contractions compress lymphatic vessels forcing lymph toward heart Contractions love lymph from one valve to the next RESPIRATORY LYMPH (flow of lymph) Inhalation: diaphragm contracts and increases abdominal pressure Exhalation: diaphragm relaxes Higher abdominal pressure: pushes lymph toward thoracic region Lower abdominal pressure: back flow is prevented by valves LYMPHATIC ORGANS AND TISSUES Widely distributed throughout the body and its purpose is to facilitate immune response. PRIMARY LYMPHATIC ORGANS: Bone marrow and thymus Stem cells divide, immunocompetent SECONDARY LYMPHATIC ORGANS: Spleen, lymph nodes, tonsils, etc. Where most immune responses occur THYMUS: Bi-lobed Has a capsule that separates lobes into lobules Lobules are composed of outer cortex, inner medulla and lymphocytes are found in reticular mesh Spherical structures, thymic corpuscles composed of keratinized epithelial cells Function: Lymphocyte development Secretes thymosin which stimulates cell division and T cell maturation T cells attack foreign or abnormal cells LYMPHOCTES: Lymphocytes account for 25% of circulating WBCs There are 3 classes of circulating lymphocytes: T Cells (thymus) Cytotoxic, helper, regulatory B Cells (bone marrow) Plasma cells (antibodies) NK cells (natural killer) Continual monitoring SPLEEN Below diaphragm, above left kidney, above descending colon, and behind fundus of stomach Has a fibrous capsule that is divided into compartments White pulp: lymphocytes (immune) Red pulp: platelets are stored, and old red cells are destroyed Function It is the largest collection of lymphoid tissue in the body Defense: macrophages remove microbes from blood Hematopoiesis: monocytes and lymphocytes activated RBC/platelet destruction: macrophages remove worn out RBCs and imperfect platelets Blood reservoir: self transfusion LYMPH NODE Enclosed by a fibrous capsule Lymph enters by several afferent vessels, emerges by a single efferent vessel One way valves When infection present B cells activate to become antibody producing cells Function: Defense: remove microbes and other injurious particles Mechanical filtration stops particles progressing in body Biological filtration phagocytosis to destroy particles Hematopoiesis: Final stages of maturation of some lymphocytes and monocytes Adenitis: infection of node Hodgkin disease: cancer of lymph system – nodal enlargement TONSILS: Masses of lymphoid tissue Protective pharyngeal lymphoid ring Palatine tonsils, pharyngeal tonsils, lingual tonsils First line of defense from exterior Subject to chronic infection or tonsilitis ROLES OF THE LYMPHOID SYSTEM IN BODY DEFENSES Non-specific defenses (innate): No distinction between threats First and second line of defense Specific defenses (adaptive) Protect against particular threats Third line of defense FIRST LINE OF DEFENSE: Skin Mucous membranes Lacrimal apparatus saliva Urine Chemicals SECOND LINE OF DEFENSE: Phagocytosis Fever Inflammation Extracellular killing (NK) Antimicrobial substances (interferons, complement, iron binding proteins, and antimicrobial proteins) ADAPTIVE IMMUNITY: Ability of the body to adapt defenses against specific antigens An antigen is a foreign substance that evokes an immune response Involves coordinated activities of T cells and B cells Cell mediated immunity: (cellular) T cells; defense against abnormal cells, infected cells. Antibody mediated immunity: (humoral) B cells; defense against antigens on body fluids IMMUNE RESPONSE: Purpose is to inactivate/destroy pathogens and/or abnormal cells this involves the activation of T cells and B cells HYPERSENSITIVITY: Beyond normal antigenic response (allergy) Occur during the first exposure to an allergen (individual becomes sensitized) Second exposure: damaging immune system response 4 principal types of hypersensitivity reactions: anaphylactic, cytotoxic, immune complex, cell mediates TYPE I (anaphylactic) REACTIONS: An immediate response 2-30minutes IgE antibodies combine with antigen Antibodies produced in response to antigen Antibodies bind to cell surfaces Localized: common allergic conditions Systemic: shock, difficulty breathing, death Triggers degranulation MEDIATORS: Histamines: increased permeability, vasodilation increased mucous secretion, smooth muscle contraction Leukotrienes: prolonged contraction of smooth muscles Prostaglandins: affect smooth muscles of respiratory system and increase mucous secretion These all serve as chemotactic factors They attract neutrophils, eosinophils to degranulated cells and activate factors causing an inflammatory response TYPE I LOCAL ANAPHYLAXIS: Triggered by inhaling antigen and ingesting antigen TYPE I SYSTEMIC ANAPHYLAXIS Anaphylactic shock Exposure to sensitized antigen Release of mediators causes vasodilation of peripheral blood vessels and a drop in BP Treatment: Preloaded syringe of epinephrine Desensitization PREVENTING ANAPHYLACTIC REACTIONS: Skin tests: Diagnosis of allergies Inoculate small amounts of antigen beneath epidermis Desensitization: series of injections gradually increasing doses of antigen Purpose: produce IgG not IgE Goal: IgG will act as a blocker? TYPE II (CYTOTOXIC REACTION Activating complement via classical pathway = cytolysis Additional damage in 5-8 hours by macrophages Most familiar involve blood group systems – ABO and Rh antigens When a transfusion is incompatible it activates complement and lysis of donor RBCs DRUG INDUCES CYTOTOXIC REACTIONS II Thrombocytopenic purpura Haptens coating platelet surfaces Induces formation of antibodies Activated complement causes platelets to lyse and hemorrhages TYPE III IMMUNE COMPLEX REACTIONS: When antigen in excess Antibodies – antigen complexes circulate “immune complex” Trapped in blood vessels, joints, skin, kidney Triggers inflammatory damage (to capillaries) Glomerulonephritis: infection causing inflammatory damage to glomeruli TYPE IV DELAYED CELL MEDIATED REACTIONS The delay is because T cells and macrophages migrate to accumulate near antigen Cause: APC phagocytize antigen and present to T cells Activates T cell Preexposure triggers memory cells Activated T cells release cytokines with antigen contact Results in an inflammatory response TB test: Test injects protein components of bacteria into skin Bacterium is picked uo by macrophages Previous infection = delayed inflammatory response Allergic dermatitis: Haptens combining with proteins in skin HUMAN LEKOCYTE ANTIGEN COMPLES Inherited self molecules (MHC) a.k.a HLAs Help immune system recognizes self from non-self HLA typing: Identify and compare HLAs Transplant surgery (requires tissue typing) GRAFTS: Autografts: within an individual and no immune response Isografts: between identical twins and no immune response Allografts: between people (not twins) and yes immune response Xenografts: between humans and animals and yes immune response IMMUNOSUPPRESSION Prevent rejection of an allograft Some drugs suppress cellular immunity Some drugs target cellular and humoral immunity BONE MARROW TRASNPLANT Hematopoietic stem cell transplant Recipient lack capacity to produce B cells and T cells The goal is to produce healthy red blood or immune system cells GRAFT VERSUS HOST DISEASE: Transplant immunocompetent cells launch cell mediated attack against recipient tissue ABNORMAL IMMUNE RESPONSE: Immunological competence: a normal immune response Autoimmune disorder: immune response targets self cells and tissues/ b cells make antibodies against self (autoantibodies) Immunodeficiency disease: immune system fails to develop or response is bloced/ severe combined immunodeficiency disease (SCID) acquired immune deficiency syndrome (AIDS) AUTOIMMUNE DISEASES (ANTIBODY REACTIONS) Myasthenia Gravis: Antibodies prevent Ach from binding receptors Graves Disease: Antibodies mimic TSH Rheumatoid Factors: Chronic inflammation and damage to cartilage and bone Systemic lupus erythematosus: Joint pain and swelling buterfly rash AUTOIMMUNE DISEASES CELL MEDIATED REACTIONS Multiple sclerosis T cells and macrophages attack myelin sheath of nerves Insulin dependent diabetes mellitus Destruction of insulin secreting cells Psoriasis Th1 disease Drugs inhibit TNF alpha THE IMMUNE SYSTEM AND CANCER Cancerous cells transform and uncontrollable proliferation Acquire tumor associated antigen marks as non self Healthy immune system prevents most cancers but lack surface antigens, rapid division, and invisibility IMMUNOTHERAPY FOR CANCER Immunotherapy using the immune system to treat cancer Use of vaccines Therapeutic: to treat existing cancer Prophylactic: to prevent development of cancer Use of antibodies: Neutralize growth factors (HER2) responsible for breast cancer cell growth (Herceptin) Combination of antibody and toxin (immunotoxin) Chapter 23 The Respiratory System: Anatomy – Week 5 Respiratory system: the mechanics of breathing moves air into and out of the body all cells in our bodies require energy for Maintenance, growth, defense, and reproduction. Oxygen is obtained from air by diffusion across exchange surfaces of lungs and the respiratory system works together with the cardiovascular system Five basic functions of the respiratory system: Provides extensive gas exchange surface area Moves air to and from surfaces of lungs Protects respiratory surfaces from outside environment (dehydration, temperature changes, invading pathogens) Produces sounds: speech and singing Participates in olfactory sense The structure of the respiratory system includes Respiratory tract: this is the passageway that carries air to and from exchange surfaces it is structurally divided into upper and lower tracts Upper respiratory tract: not to pharynx and associated structures Lower respiratory tract: larynx, trachea, bronchial tree and lungs...functionally divided into conducting and respiratory zones Conducting zone: bring air to site of external respiration Respiratory zone: main site of gas exchange In addition, it filters, warms, and humidifies air Respiratory system the air flow: air passing through the respiratory tract traverses the: Nasal cavity Pharynx Larynx Primary bronchi (main) Secondary bronchi (lobar) Tertiary bronchi (segmental) Bronchioles Alveoli The nose: this is the entrance of the respiratory system and is divided into external and internal portions. External nose: is visible on the face and under the surface of the external nose are two openings called the external nares or nostrils Internal nose: is beyond the nasal vestibule and is divided by the nasal septum it consists of hyaline cartilage, vomer, perpendicular plate of ethmoid, maxillae, and the palatine bone. Nasal cavity: large space, 2 posterior openings internal nares, ducts from sinuses open into cavity Nasal conchae: the nasal cavity is divided by 3 nasal conchae; this is divided into breathing passages (meatuses) and are lined by skin containing coarse hairs Air flow: the air eddies and swirls trap airborne particles and turbulent flow Nasal epithelium: respiratory mucosa lines conducting portion, respiratory epithelium is pseudostratified ciliated columnar epithelium. Goblet cells secrete mucus, near superior nasal conchae olfactory epithelium Sinuses and ducts: secretions from paranasal sinuses into nasal cavity Sinuses are paired, air-filled chambers lined with mucus membranes, resonating chambers and drainage from the nasolacrimal duct Pharynx: a hollow tube posterior of internal nares & larynx and the wall is composed of skeletal muscles, mucous membrane lines. This consists of nasopharynx, oropharynx, laryngopharynx. Nasopharynx: internal nares to soft palate it is pseudostratified ciliated and exchanges small amounts of air with auditory tubes Oropharynx: soft palate to hyoid bone, stratified squamous, palatine and lingual tonsils Laryngopharynx: hyoid bone to esophagus, stratified Larynx: 9 pieces of cartilage the larynx consists of the epiglottis, thyroid cartilage, and cricoid cartilage. The larynx has 3 pairs of smaller cartilages artenoid, corniculate and cuneiform. Epiglottis: larynx elevated during swallowing and the epiglottis flods back over glottis to prevent entry Thyroid cartilage: anterior surface of larynx (the Adams apple) Cricoid cartilage: sits inferior to thyroid cartilage, provides support, also protects the glottis and trachea, and provides attachment sites for laryngeal muscles and ligaments 2 pairs of ligaments extend across larynx -> between thyroid and smaller cartilages Upper ligaments: false vocal cords Lower folds: true vocal cords Vocal cords upper ligaments: They have vestibular folds, relatively inelastic and the function holding breath against pressure in thoracic cavity Lower folds: principal structures in voice production and elastic ligament and muscles change their position Extrinsic muscles: connect cartilage & structures in throat Intrinsic muscles: connect cartilages to one another and cords Variation in pitch related to tension in the folds Pulled tight: vibration rapid and higher pitch Decreased tension: vibrate slowly and lower pitch Trachea: is considered the windpipe and located anterior to esophagus and attaches to circoid cartilage and branches form the bronchi Tracheal wall: semi circular cartilaginous rings and protects airway, preventing collapse or overexpansion, C-shaped opening attached by trachealis muscle Bronchi: primary main bronchi at T5 – right primary bronchus is shorter, steeper, wider At the hilum primary bronci divide the secondary lobar bronchi one for each lobe of lung Secondary bronchi branch into the tertiary segmental bronchi Tertiary divide repeatedly into bronchioles and cartilage changes Bronchioles: diameter of passageway narrows cartilage has disappeared, and walls are dominated by smooth muscle Diameter controls amount of resistance Sympathetic: bronchio dilation Parasympathetic: bronchio constriction Extreme constriction can block passageways Asthma attack and allergic reaction Cystic fibrosis: viscous mucous impairs cilia and clogging passageways Terminal bronchioles: bronchioles branch into terminal bronchioles and supplies air to a lobule of lung (each lob gets a terminal bronchiole Lobule: small compartment within a lung segment bound by C.T. Terminal bronchiole divides to form several respiratory bronchioles Bronchial tree: the bronchial tree begins at trachea and ends at terminal bronchioles this is the conducting zones Alveolar ducts and alveoli: respiratory bronchioles open into alveolar ducts and the ducts ar the end of the alveolar sac (connects multiple alveoli) Alveoli: exchange surfaces, simple squamous, septal cells, secrete surfactants Emphysema: inflammation leading to destruction of alveolar walls Respiratory membrane: gas exchange occurs at respiratory membrane of alveoli Simple squamous epithelial cells (line alveoli) Endothelia cells (line capillary) Fused basemen membranes (between) Lungs: the lungs are divided by fissures the right has 3 lobes and the left 2 lobes Costal mediastinal surfaces Hilum Left lung indented cardiac notch Elastic fibers Lung in pleural cavity lines with serous membrane pleura Thoracentesis: examining pleural fluid Pneumonia: inflammation Pneumothorax: air in pleural cavity Hemothorax: blood in pleural cavity Respiratory physiology: an integrated set of regulated processes that include the following External respiration: pulmonary ventilation and gas exchange in pulmonary capillaries of lungs Transport of gases by blood Internal respiration: gas exchange in systemic blood capillaries and cellular respiration Overall regulation of respiration Pulmonary ventilation (a.k.a breathing ) Inspiration: movement of air into the lungs Expiration: movement of air out of the lungs What is the mechanism of pulmonary ventilation? Air moves in and out of lungs because pressure in one place is different from that in the other place this creates a pressure gradient Gas always moves down its pressure gradient So how does this apply to pulmonary ventilation? When atmospheric pressure is greater than pressure within lungs, air flows down this gas pressure gradient moving from atmosphere into the lungs this is inspiration. When the pressure in the lungs becomes greater than atmospheric pressure, air moves down its gas pressure gradient, air moves out of lungs into atmosphere this expiration PA: pressure within alveoli of lungs PB: pressure of the atmosphere Under standard condition sit in he atmosphere exerts a pressure of 760mm Hg PIP: the fluid pressure of pleural fluid Referred to as intrathoracic pressure The pressure gradients are established by changes in the size of thoracic cavity? The volume of a gas varies inversely with pressure at a constant temperature Expansion of thorax results in a decreased intrapleural pressure – this leads to a decrease alveolar pressure that causes air to move from the outside into the lungs Compliance: the ability of the lungs and thorax to stretch The movement of air during inspiration and expiration is the net diffusion from high to low Balloon model of ventilation: While pulling the diaphragm downward the thoracic volume increases and causes a decrease in intrapleural pressure this results in a decrease in the alveolar pressure (PA) Creates a pressure gradient that results in flow of air into the balloon When the diaphragm recoils: thoracic volume decreases which increases internal air pressure (PA) forcing air out of the ballon Human mechanism of ventilation: - alteration between inspiration and expiration is called the respiratory cycle - contraction of the diaphragm alone or with external intercostal muscles prodcues quiet inspiration - contraction = longer thoracic cavity - enlarges thorax from front to back and from side to side - contraction of the sternocleidomastoid, perctoralis minor, and serratus anterior muscles aid during forceful inspiration - as the size of the thorax increases intrapleural and alveolar pressure decreases causing inspiration - as the thorax increases intrapleural and alveolar pressure decreases causing inspiration Pulmonary volumes and capacities: Important air movement maintained within normal limits appropriate exchange of O2 and CO2 A spirometer measures volume of air exchange in breathing Spirogram Tidal volume: volume of air in one breath Minute ventilation (MV): total air inhaled and exhaled in 1 (=TV x respiration rate Inspiration reserve volume) Inspiratory reserve volume (IRV): amount of air forcibly inspired over and above a normal inspiration Expiration reserve volume: amount of air that can be forcibly expired over and above a normal expiration FEV1- amount of air forcefully expired in 1 second Residual volume: some air remains trapped in the alveoli that cannot be forcibly expired Sudden impact to the thorax or a series of deep coughs results expiratory volume being forced out of our airways As well as some of your residual volume Only a few alveoli collapse Pulmonary capacity The sum of 2 or more pulmonary volumes Vital capacity + the sum of the IRV+TV+ERV Largest of air an individual can move in and out of the lungs Depends on side pf the thoracic cavity and posture Forced vital capacity: is the volume of air forcefully expired after maximal inspiration Inspiration capacity: maximal amount of air an individual can inspire after a normal expiration (IC= TV + IRV) Functional residual capacity = the amount of air led tin the lungs at the end of a normal expiration (FRC = ERV+RV) Total lung capacity = total volume of air a lung can hold (TLC = TV + IRV + RV) Alveolar ventilation: Volme of inspired air that reaches alveoli Volumes of air takes part in exchange of gases between air and blood When we breath we breath dead air The larger filled passageways are said to constitute the anatomical dead space Chronic obstruction pulmonary disease Some alveoli not able to perform gas exchange = dead space Anatomical and alveolar dead space make up the physiological dead space A general rule: 70% of TV is your alveolar ventilation volume and 30% is dead space Eupnea, hyperpnea, dyspnea, orthopnea, apnea, hyperventilation, and hypoventilation Partial pressure PP Pressure exerted by one gas in a mixture of gases or liquid PP of a gas is directly related to the concentration of that gas in a mixture Alveoli air is the environment surrounding blood moving through the pulmonary capillaries Standing between blood and air are thin membranes Highly permeable to oxygen and carbon dioxide Gas molecules diffuse into a liquid from its environment and dissolve in the liquid until the PP of the gas solution become equal to its partial pressure in the environment of the liquid By the time blood leaves the pulmonary capillaries diffusion and approximate equilibrium of oxygen and carbon dioxide across membranes has occurred Exchange of gases in the lungs: Between alveolar air and blood flowing through lung capillaries Gases must cross the barrier between the external and internal world Gases move in both directions' oxygen enters the blood PO2 of alveolar air is greater than PO2 of blood carbon dioxide exiting the blood PCO2 of venous blood is greater than PCO2 of alveolar air In capillaries blood travels in a layer so thin each RBC comes close to alveoli air Determining O2 diffusion: Oxygen pressure gradient (high altitudes) Functional surface area of respiratory membrane (emphysema) Respiratory minute volumes (morphine) Alveolar ventilation How blood transports gases Blood transports oxygen and carbon dioxide either s solutes or combines with other chemicals Dissolves in plasma Most forms a chemical union with some other molecules Once gas has bound to another molecules, plasma concentration decreases more gas can diffuse into plasma this allows larger volumes of gases to be transported Transport of oxygen Oxygen –Hb is dissociating curve: Increase blood PO2 accelerates Hb association with oxygen (Hb+oxygen = HbO2) Decreased PO2 – oxygen dissociation from oxyhemoglobin Dissolves oxygen diffuses out of arterial blood and blood PO2 decreases while it accelerates oxyhemoglobin dissociation, more oxygen released into plasma for diffusion to cells Systemic gas exchange: Internal respiration is the exchange of gases between arterial blood and cells O2 diffuses out of blood Blood PO2 decreases CO2 exchange between tissues and blood in opposite direction Catabolism creates CO2 pressure gradient causing diffusion of CO2 from tissues into blood Transport of carbon dioxide: Solutes are small (10%) od co2 dissolves in plasma Carbaminohemoglobin some (20%) blood CO2 combines with NH2 groups of Hb and other proteins Bicarbonate ions (70%): when co2 dissolves in blood plasma some associate s with water to form carbonic acid (carbonic anhydrase Some dissociates to hydrogen and bicarbonate ions (HCO3) Regulation of pulmonary function: Respiratory control centers: main integrators controlling nerves that affect inspiratory and expiratory muscles are located in the brainstem Maintain relative constancy of blood PO2 and PCO2 by controlling the rate and depth of breathing Regulation of pulmonary function: Medullary respiratory center Ventral respiratory group: basic rhythm generator Dorsal respiratory group integrates info from chemoreceptors for PCO2 Signals VRG to alter breathing rhythm to restore homeostasis Basic breathing rhythm altered at pons Pontine respiratory group: input to DRG and VRG to modify breathing during exercise and sleeping Chapter 24 Week 6 – The Digestive System Anatomy The digestive system: provides fuel to keep all the body’s cells functioning. It also supplies building blocks needed for cell growth and repair. The digestive system consists of a muscular tube, digestive tract, and accessory organs. Functions of the digestive system: Ingestion: occurs when food enters the digestive tract through the mouth Mechanical processing: physical manipulation of solid foods Tongue and teeth in oral cavity Digestion: the chemical breakdown of food into smaller fragments Secretion: the release of water, acids, enzymes, buffers by the digestive tract and glandular accessory organs Absorption: movement of small molecules, electrolytes, vitamins, water across digestive epithelium and into interstitial fluid Excretion: is the removal of wastes from body fluids Waste is compacted and discharged as feces (defecation) The digestive tract: lining Plays defense roles: Protects tissues from corrosive destructive acids and enzymes Protects against bacteria swallowed or within digestive tract Epithelium and secretions: Nonspecific defense agasint bacteria Bacteria that reach underlying tissues are attacked by macrophages and other immune system cells MALT Peyer's patches 4 major layers: From the lower esophagus to the anal canal there are four layered arrangements of tissues From deep to superficial they consist of: Mucosa Submucosa Muscularis Serosa/adventitia Mucosa membrane in the (pharynx, esophagus, anus): A mucous membrane that is stratified epithelium (pharynx, esophagus, anus) Function: serves as protection where mechanical stress is severe Mucosa membrane in the stomach and intestines: It has epithelial folds for expansion and increasing surface area. It is simple columnar with goblet cells and in the small intestine the columnar cells have microvilli Function: absorption Submucosa: It has a layer of C.T. that connects mucosa and muscularis layers. It also has a network of nerve fibers called submucosal plexus which controls and coordinates: Contractions of smooth muscles Secretion of digestive glands Muscularis externa: Smooth muscle: has an inner circular and outer longitudinal layer. The contractions agitate and propel material along the tract. This layer also has a myenteric plexus which is an autonomic reflex under nervous control it is located between muscular layers, and it controls peristalsis. Serosa: This is a serous membrane which forms a portion of the visceral peritoneum and is continuous with parietal peritoneum. Adventitia: is connective tissue covering the oral cavity, pharynx, esophagus, and rectum. This helps connect surrounding structures. Peritoneum: Peritoneum is the largest membrane in the body. It has a visceral and parietal layer. The space between the layers is called the peritoneal cavity and it is filled with serous fluid. Some organs are only covered on the anterior surface, for example the kidneys, pancreas, duodenum, ascending/descending colon. These have retroperitoneal The peritoneum has large folds that bind organs together and to cavity walls, for example blood vessels, lymphatics, and nerves. Different types of peritonea: Greater omentum Falciform ligament Lesser omentum Mesenteries Mesocolon Greater omentum: drapes a “fatty apron” over the transverse colon and small intestine Falciform ligament: Attaches liver to anterior wall and diaphragm Lesser omentum: Suspends the stomach and duodenum from the liver Mesenteries: Helps stabilize the position of the abdominal organs and prevents intestines from becoming entangles Mesocolon: Binds transverse and sigmoid colon to posterior abdominal wall The mouth: Oral or buccal cavity and is stratified squamous epithelia Lips: Fleshy folds containing orbicularis Oris muscle Inner surface attached to the gum by the labial frenulum Cheeks: The lateral walls of the oral cavity and together the lips, cheeks, teeth, and gums form the oral vestibule Palate: Separates oral nasal cavity and forms roof of the mouth Hard palate: anterior formed by maxillae & palatine bones Soft palate: posterior formed by arch-shaped muscle between oro and nasopharynx Uvula: Hangs from free border of soft palate and is drawn superiorly during swallowing Palatine tonsils: Situated between the double arches of the soft palate Lingual tonsils: At base of tongue Salivary glands: There are 3 pairs of salivary glands that secrete saliva into the oral cavity. While at rest it cleanses the mouth and teeth. It is controlled by the ANS. Secretions increase when food enters mouth to lubricate, dissolve, and begin food breakdown. Parotid Submandibular Sublingual Tongue: The tongue is a skeletal muscle, sensory analysis by receptors. A portion of the tongue in the oral cavity. A portion of the tongue is found in the oral cavity while the base of the tongue is in the oropharynx Extrinsic muscles: move the tongue from side-to-side and in-and-out Intrinsic muscles: alter its shape and size for speech and swallowing Lingual frenulum: limits posterior movement Ankyloglossia: is the abnormal short or rigid lingual frenulum this is also called tongue tied and could result in speech impairment Teeth (dentes) These are surfaces performing chewing or mastication they are located in alveolar sockets lined by periodontal ligaments. The bulk of the tooth is made up of dentin and the central of the tooth is the pulp cavity. There are 3 major external regions: Crown: visible portion is covered by enamel Root: embedded into the socket Neck: junction between crown and root Humans have 2 sets of teeth: Deciduous (20) Permanent (32) Pharynx: The pharynx is a common passageway for digestive and respiratory systems it also cooperates with the oral cavity and esophagus to initiate swallowing. Esophagus: The esophagus is posterior to the trachea and inferior to the pharynx. It passes through the thoracic cavity, diaphragm, and empties in the stomach where the esophageal hiatus (this is the opening to the stomach). It is stratified epithelial Superior 1/3: skeletal muscle Middle 1/3: skeletal + smooth muscle Inferior 1/3: smooth muscle In the esophagus sphincters are situated at each end of the tube: Upper sphincter: skeletal; regulates movement from pharynx Lower sphincter: smooth; regulate movement into the stomach The incompetence of the lower sphincter results in gastroesophageal reflux disease (GERD) which manifests as heart burn Stomach: The stomach is situated between the esophagus and the first part of the small intestine 4 main regions of the stomach: Fundus Body (bulk) Pyloric antrum Pyloric canal There are also 3 layers of muscles they consist of (longitudinal, circular, and oblique) Greater curvature: lateral border Lesser curvature: medial border Pyloric sphincter: regulates flow of chyme into the small intestine The stomach also has rugae which has folds in the empty stomach this enables distension Gastric pits: depressions lead to gastric glands Gastric glands: extend into lamina propria and secrete gastric juices Gastric pits and gastric glands function as temporary storage, mechanical and chemical breakdown, production of intrinsic factor, secrete gastrin into blood, and the protection of microorganisms SMALL INTESTINE Divided into 3 regions Duodenum: segment closest to stomach Jejunum: bulk of chemical digestion and nutrient absorption Ileum: ends at ileocecal valve controls flow of material into the cecum of the large intestine INTESTINAL WALL Deep crevices and cells secrete intestinal juices Plicae circulares Vili to increase surface area Microvilli found in the brush border and contains enzymes Lacteal: lymphatic capillary LARGE INTESTINE: Begins at ileum and ends at anus Below stomach and liver and almost completely frames the small intestine Functions: Reabsorption of water ions Absorption of important vitamins Moves contents from colon into rectum Compact intestinal contents into feces Store fecal material prior to defecation Cecum: Appendix attaches here Colon: Ascending, transverse, descending, sigmoid Rectum: End of digestive tract Temporary storage of feces Anal canal: Opening to exterior -> anus Guarded by internal and external sphincters LIVER 2 main lobes the right lobe which is larger and the left lobe which is smaller The lobes are separated by the falciform ligament Liver is divided into lobules Liver cells are hepatocytes Central vein that radiates to liver cells and sinusoids Phagocytic kuppfer cells PORTAL TRIAD Blood enters sinusoids via branch of hepatic portal vein and hepatic artery Blood flows through sinusoids Hepatocytes absorb solutes and secrete materials Bile flows away from hepatocytes into bile duct 1,2,3 from the portal triad Blood leaves sinusoids through central vein Merge to form hepatic vein which empties into the inferior vena cava LIVER: BILE Hepatocytes secrete fluid (bile) Release into channels to ductules to ducts Ducts merge and exit liver as common hepatic duct which joins the cystic duct from the gallbladder to form the common bile duct Metabolic regulation Monitors composition of blood Adjusts circulating levels of organic nutrients Hematological regulation Remove RBCs, debris, pathogens Make plasma proteins GALLBLADDER Stores and concentrates bile Water is absorbed and salts concentrated Too concentrated salts precipitate forming gall stones PANCREAS Clusters of epithelial cells Exocrine (99%) acinar units secrete pancreatic juice Endocrine (1%) produce hormones Neutralizes chyme in duodenum with enzymes and buffers WEEK 6 DIGESTIVE SYSTEM PHYSOLOGY MECHANICAL DIGESTION: Involves all motility of digestive tract to carry out the following Change ingested food from solid into minute particles Mix digestive juices with GI contents by churning Move food along digestive tract by propulsion Mastication Mix food with saliva and prepares for deglutition DEGLUTITION: Coordination of muscles Respiration is inhibited 1. Buccal phase (voluntary) - food bolus forced into pharynx by tongue 2. Pharyngeal Phase (involuntary) - pharynx propels bolus into esophageal tube 3. Esophageal Phase (involuntary) Reflexes in skeletal and smooth muscle move bolus toward stomach PERISTALSIS: Food enters lower portion of esophagus Motility produced by peristalsis Bolus stretches GI wall contraction of circular muscle triggered and pushes bolus forward Process continues as long as the bolus stimulates stretch reflex REGULATING MOTILITY Digestion in stomach almost immediate Storage Time: Carbohydrates: least High protein: longer Triglyceride heavy: longest Propulsion Retropulsion Chyme injected into the duodenum every 20 seconds Gastric emptying regulated to prevent overburdening duodenum Hormonal control GIP released when nutrients enter duodenum, and this decreases peristalsis Nervous control: Receptors in duodenum sensitive to acids and distension and decreases peristalsis (enterogastric reflex) SEGMENTATION: Motility produced by segmentation Dogestive reflexes cause a forward and backward movement in a segment of GI tract Mixes food and digestive juices Facilitates absorption through contact with mucosal lining of tract Peristalsis and segmentation may alternate in sequence BODY USES 3 NUTRIENT MONOMERS Glucose Fatty acids Amino acids ENZYME COMPONENTS Some protein enzymes complete Others made of protein and non-protein portion Apoenzymes: protein portion (alone is inactive) Cofactors and coenzymes: Inorganic ions: Fe, Mg, Ca, are cofactor Vitamins or vitamin containing substances are coenzymes CARBOHYDRATES: Macronutrients, sugars, complex polysaccharide Amylases Contact digestion: disaccharides bind enzymes in brush border PROTIEN: 9 essential 11 non-essential A complete protein supplies all essential amino acids and incomplete lacks one or more Peptides are shorter chains of amino acids Pepsin (gastric) Trypsin and chymotrypsin (pancreatic) OMEGA 3 and 6 3 is an essential fatty acid Fish oil, Seaweed, Flaxseeds, Chia seeds 6 is an essential fatty acid and is found in vegetables, oils, nuts and seeds LIPIDS Non polar Form large globules in water Forms a micelle VITAMINS: Most are acquired from diet Micronutrient FAT SOLUBLE: “DEKA” absorbed as micelles and excess is stored in adipose tissue WATER SOLUBLE: not stores in diet (al the b’s and c’s) MINERALS: All are essential 7 major: Ca, Cl, Mg, P, K, Na, S Trace elements are: I, Fe, Se, Zn DIGESTIVE SECRETION OF ORAL CAVITY SALIVA Mostly water Amylase Lipase Sodium bicarbonate Anti-microbial substances DIGESTIVE SECRETION STOMACH GASTRIC JUICE Gastric glands in stomach walls Chief cells – inactive pepsinogen Parietal cells – HCL this activates pepsinogen (pepsin) and stimulates hormone release of G cell Parietal cells also release intrinsic factor which facilitates the absorption of b12 which is necessary for making RBCs Pernicious anemia: vit b12 deficiency Neck cells DIGESTIVE SECRETION PANCREAS – PANCREATIC JUICE Enzymes secreted as inactive precursors (zymogens) Trypsinogen and chymotrypsinogen (protein) Lipases (fat) Nucleases (nucleic acids) Amylase (starch Sodium bicarbonate (neutralize chyme) DIGESTIVE SECRETION LIVER AND GALLBLADDER BILE AND INTESTINAL JUICE Bile: Common bile duct delivers bile to duodenum Bile salts emulsify Sodium bicarbonate neutrilize chyme Other substances for removal from the body (excretions): cholesterol, bile pigments (bilirubin) Gray feces = possible low bile secretion Intestinal juice: Water Electrolytes Mucous CONTROL OF GLAND SECRETION: Glands secrete when food is imagined, seen, smelt, or tasted Nervous and hormonal controls direct flow of juices and salivary glands receive impulses from the brainstem CONTROL OF GASTRIC SECRETION 3 PHASES CEPHALIC PHASE (head) Sensations to brainstem Nerve signals to stomach Gastric juice increases G cells release gastrin GASTRIC PHASE Food reaches pyloric portion of stomach Distension releases gastrin into blood stream and activates mixing waves Gastric glands increase secretions of gastric juices INTESTINAL PHASE Chyme enter duodenum Nervous regulation by enterogastric reflex CIP, CCK, and secretin are released for hormonal control CONTROL OF PANCREATIC SECRETION: Triggered by hormones released by duodenum GIP release of endocrine hormones CCK release of pancreatic juices Secretin fluid to neutralize chyme CONTROL OF BILE SECRETION Secretin and CCK stimulate release of bile CONTROL OF INTESTINAL SECRETION Stimulated by pH ABSORPTION: Digested foods move through intestinal mucosa into blood/lymph Most absorption takes place in small intestine In the blood stream: monosaccharides, amino acids, water soluble vitamins and minerals are absorbed Into lymph: fatty acids, monoglycerides, and fat-soluble vitamins are absorbed Fluids 9.3 L total volume entering small intestine per day 8.3 L what the small intestine absorbs 0.9 L large intestine absorbs 0.1 L of water is excreted in feces METABOLIC STATES: Absorptive states: insulin driven Period during which nutrients absorbed up to 4 hrs after eating Mainly glucose used by cells as main fuel Glycogenesis, lipogenesis, protein synthesis Post absorptive state: glucagon driven 4 hours after eating (nutrient depending) Supply of nutrients ends Glucose sparing events leads to the breakdown of proteins in muscle cells Gluconeogenesis, glycogenolysis, and lipolysis BODY MASS Amount of matter in the body BODY WEIGHT Force exerted on mass by gravity ELIMINATION: Defecation: Rectum emptying until peristalsis moves fecal matter out of colon Distension stimulates stretch receptors causing defection reflex (relaxes) Feces: Water, salts, epithelial cells, bacteria, products of bacterial decomposition, unabsorbed/indigestible parts of food Constipation: decreased motility = extra water absorbed Diarrhea: increased motility = reduced water electrolytes absorption WEEK 8 URINARY SYSTEM Overview: processing blood plasma, water content is adjusted by body maintaining constancy in internal environment, important ions such as Na and K are adjusted, and blood pH can be altered to match the range of limits. The urinary system is regulating internal fluid environment and overall homeostasis URINARY SYSTEM FUNCTIONS: Excretion: removal of metabolic waste products Elimination: discharge of waste product into environment Homeostasis: Blood ionic composition: regulate blood levels of several ions Blood pH: excretion of H+ conservation of bicarbonate ions (buffers) Blood volume: conserve/eliminate water in urine Blood pressure: secrete renin Hormone production: calcitriol (vit D) and erythropoietin Blood glucose levels: regulate levels via glucogenesis ELIMINATION: Urinary system plus integumentary, respiratory, digestive, contribute to body's efforts to remove wastes Only the urinary system finely adjusts water and electrolyte balance to degree required for normal homeostasis of body fluids URINARY SYSTEM KIDNEYS: Principle organ and produces urine Left kidney slightly larger than the right and lie retroperitoneal Extend from T12-L3 Renal fat pad CT anchors kidneys Hilum: medial surface where the ureter, blood and lymphatic vessels and nerves attach White Fibrous Capsule: barrier to trauma and helps maintain shape, anchors Renal cortex: outer region, extends from capsule to base of pyramids and space between them (columns) columns contain blood vessels Renal Medulla: inner region Renal pyramids: (8-18) wedges of medullary tissue (base faces renal cortex and apex towards the hilum) renal papilla is the tip Renal Lobe: a renal pyramid and ½ of each adjacent renal column Nephron: functional unit within the cortex/medulla Calyx: where urine is collected for transport out of body (cup-like) Minor Calyces: cup that drains from renal papilla (branches join together to form major calyces) Major Calyces: join together to form a collection basin (renal pelvis) Pelvis: exits hilum to become the ureter (collects and drains away fluid) Papilla, minor, major, pelvis, ureter HOMEOSTATIC IMBALANCES: Renal calculi: Crystals of salts present in urine precipitate, solidify into stones. This is kidney stones it is an excessive calcium and low water intake, abnormally alkaline/acidic urine and overactivity of the parathyroid gland Lithotripsy: high energy shock waves to disintegrate kidney stones (alternate to surgery) Polycyclic kidney disease: inherited disorder, kidney tubules become riddled with lots of cysts it is a progressive disease and is the inappropriate apoptosis in a non-cystic tubule leads to progressive impairment and renal failure. PATH OF BLOOD FLOW: Renal artery Segmental artery Interlobar artery Arcuate artery (in cortex) Interlobular arteries Afferent arterioles Glomerular capillaries Efferent arterioles Peritubular capillaries (renal portal system) Interlobular veins Renal veins URETERS 2 tubes that convey urine from kidneys to urinary bladder Retroperitoneal and course into pelvis until it reaches bladder Bottom of bladder Lined with transitional epithelium (when ureter relax cells have more of cuboidal shape, they look spherical and then when contracted they look flattened) 3 layers Mucous lining Muscular layer Fibrous outer layer Muscular layer is smooth muscle that propels urine by peristalsis URINARY BLADDER A collapsible bag. (posterior to pubic symphysis) Wall made up of mostly smooth muscle (detrusor muscle) Lined with mucous transitional epithelium and form folds called rugae this allows for great distension There are 3 openings on the floor of the bladder: 2 ureters and one urethra. Ureters open in the corners of the triangle shaped floor the trigone Functions: Reservoir for urine and with the urethra it expels urine from the body URETHRA Small tube lined with mucous membrane and leads from floor of bladder to exterior of body FEMALE URETHRA: Diresctly behind pubic symphysis and passes through muscular floor of pelvis Extends down and forward from the bladder to opening at external urinary meatus and the path is 3 cm. MALE URETHRA: Passes through prostate gland after leaving bladder Joined by 2 ejaculatory ducts then extends down, forward up to enter base of penis ending as a urinary meatus 20 cm path Urine prevented from mixing with semen by reflex closure of sphincter muscles NEPHRON: Functional unit of the kidney and its function is blood plasma processing and urine formation Millions of nephrons It is made of 2 parts a renal corpuscle (filters blood plasma) and a renal tubule (filtered fluid is processed) NEPHRON: RENAL CORPUSCLE: CAPILLARIES This is the first part of the nephron and is made up of the bowmans capsule and glomerulus Capillaries push into bowman it is double walled (parietal and visceral) these layers form the capsule Fluid from blood first filters put of glomerulus and into capsule NEPHRON RENAL CORPUSCLE BOWMANS Bowman's capsule has 2 layers of epithelia separated by a space called the capsular space (anything that enters capsular space is now called filtrate) Fluids waste products and electrolytes pass through fenestrated capillaries and enter capsular space and is now filtrate Filtrate is collected in capsular space Processed in renal tubule to form urine Filtrate has to pass through 3 parts: Visceral layer of bowman's capsule: Composed of podocytes Pedicles wrap around capillaries Filtrations slits are packed closely together CT mesh (slit diaphragm – prevents slits enlarging) *parietal layer does not play a role in producing glomerular filtrate Glomerulus Capillary network surrounded by bowman capsule Capillary walls composed of a single layer of endothelial cells, and these contain pores or fenestrations necessary for filtration Mesangial cells twist between glomerular capillaries and support cells with phagocytic function Basement membrane: Between podocytes (capsule) and endothelium (glomerulus) *these three layers form the filtration membrane - into filtrate is water, metabolic wastes, ions, glucose, fatty acids - RBC, WBCs, and large proteins (albumin) stay in blood NEPHRON: RENAL TUBULE Extends from corpuscle to collecting duct (filtrate is processed in renal tubule part in cortex other part in medula) PROXIMAL CONVOLUTED TUBULE (PCT) This is the first part of the renal tubule (in cortex) Nearest to bowman's Simple cuboidal and have microvilli to increase surface area because bulk of reabsorption takes place here Microvilli project into lumen to form brush border NEPHRON LOOP (LOOP OF HENLE) As filtrate descend into medulla and ascend back up to cortex Descending limb is thin Ascending limb is thin And other part of ascending limb is thick Length is important in producing concentrated or dilute urine DISTAL CONVOLUTED TUBULE (DCT) Conducts filtrate out of nephron into collecting duct Contains the juxtaglomerular complex Found in cortex Sits close to corpuscle because it has to be able to communicate with the corpuscle This is the fine tuning of the urine based on bodies needs and it is communicated through the juxtaglomerular complex Nephron ends and filtrate enters collecting ducts Collecting duct is not apart of nephron TYPES OF NEPHRONS: Cortical: 80% Renal corpuscle lies in cortex Short nephron loop that barely dips into medulla Blood supplied to nephron loop by peritubular capillaries (surround cortical nephron) Juxtamedullary: 20% Renal corpuslcle lie in cortex close to medulla Long nephron loop dips far into medulla Blood supplied to nephron loop by vasa recta (capillaries processing filtrate specific for juxtamedullary processes) Makes concentrated urine WEEK 9 URINARY SYSTEM PHYSIOLOGY Processes that allow us to produce urine: Glomerular filtration: Movement of water and solutes from plasma in glomerulus across capsular membrane into capsular space Renal corpuscle Collects filtrate in capsular space Tubular reabsorption: movement of molecules out of various segments of tubule into peritubular blood takes substances out of filtrate and puts it back into blood Tubular secretion: movement of molecules out of peritubular blood and into tubule for excretion Get rid of substances the body does not want to keep takes stuff from in blood into tubules to become a part of the filtrate Get rid of a substance that wasn't filterable FILTRATION Exclusively in renal corpuscle across capillary wall Takes place across filtration membrane Substances small enough to cross membrane will do so Filtration happens because of a pressure gradient between the blood and the filtrate of the capsular space Pressure gradient exists because of the efferent arteriole bringing blood in and then leaves through the afferent. The afferent arteriole is wider which means greater blood flow in the capillaries and slower blood flow out of the capillaries therefore pressure builds. Because efferent is smaller it limits blood flow out causing pressure to rise. Pressure gradient allows for GFR (glomerular filtration rate) and it is the amount of filtrate formed by both kidneys per minute usually in adults 125mL/min Hydrostatic pressure (HP): It is the force of fluid on walls of its container which pushes fluid out of the container (pushes against wall) Colloid osmotic pressure (COP) Created by proteins or solutes in the environment that pulls fluid into the environment Wants to pull water in towards colloid *Water moves out when HP is greater than COP and in when COP is greater than HP (HP and COP are opposing pressures and which ever is greater fluid will either move in or out) URINARY PHYSIOLOGY FILTRATION Glomerular hydrostatic pressure (GHP): The container is glomerular capillaries and the second the capsular space. This is referring to the hydrostatic pressure withing the glomerular capillaries where our blood is and plasma + water and water starts to push against the wall of the glomerular capillary wanting to push out against capillary wall and wants to go into capsular space Capsular colloid osmotic pressure (CCOP) Created by solutes already in the filtrate Referring to capsular space and the solutes in that space. Colloids have an affinity for water and pull water towards them and also encourage fluid to leave the glomerular capillaries to move into the capsular space Forces 1+2 work together Glomerular colloid osmotic pressure (GCOP) Glomerular meaning a pressure force withing capillaries and colloid is the solutes trapped inside the blood capillaries Created mostly by protein in blood Solutes have an affinity for water Capsular Hydrostatic Pressure (CHP) Generated as capsular space rapidly fills with new filtrate Pressure being exerted from the capsular space hydrostatic is fluid in capsular space pushing against the wall Pressures ¾ work together to pull or push fluid into glomerular capillaries EFP: is a combination of 4 forces EFP = (GHP + CCOP) - (GCOP + CHP) (push fluid out sum – push fluid in sum) 2 encourage plasma to filtrate and 2 encourage filtrate to plasma EFP favors filtration as GHP is greater than sum of forces that oppose filtration Domination pressure force is GHP is directly correlated with the bodies systemic blood pressure GLOMERULAR FILTRATION RATE (GFR) 180L/day filtrate GFR can be affected by different changes in the body Afferent/efferent arteriole diameter: An increase in EFP = an increase in GFR Systemic blood pressure If GFR decreases kidneys maybe unable to carry out their function A decrease in BP = a decrease in GFR Renal failure is a decrease or cessation of glomerular filtration REGULATION OF GFR Myogenic mechanism As BP increases stretching triggers smooth muscle contraction in afferent arterioles resulting in a decrease in blood flow and a decrease in GFR. As BP drop arterioles dilate and blood flow and GFR increases Vasoconstriction: decrease blood flow into the glomerulus Vasodilation: increase blood flow into the glomerulus Localized response happening within kidneys Tubuloglomerular Feedback Sometimes myogenic mechanism isn't enough to regulate GFR therefore we have a second regulatory system Helps regulate the size of afferent and efferent arterioles and allows a set off a system wide communication comes from 2 types of cells the macule dense and the juxtaglomerular they communicate with each other Regulates resistance (size) in afferent and efferent arterioles Depends on functioning maculae densa cells and juxtaglomerular cells Macula Densa: Part of the distal canulated tubule which sits close to afferent arterial and renal corpuscle These cells are chemoreceptors (determining what the status of the filtrate is in the DCT)(status meaning solute levels) Columnar tubule cells crowd together Final part of ascending limb makes contact with afferent arteriole Juxtaglomerular Cells: Fibers Mechanoreceptors (detects if the well of afferent is stretching too much or if there is not enough constriction) Found around afferent arteriole and some arounf efferent Macula communicate and tells juxta what's happening Contains renin granules Macula and juxt cells secret 2 hormones (erythropoietin which stimulate production of RBC and the second hormone is renin which is released when densa says solutes/GFR are too low renin sets off a series enzymatic reactions These sereies of enzymatic reactions are known as RAS RASS – RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM If densa cells say too low juxta release renin and renin allows to catalyze reactions taken place. Release of renin causes release of aldosterone which increases blood volume and pressure So if BP drops near JA Enzyme renin is secreted Converts angiotensinogen to angiotensin I Lungs: angiotensin I split by angiotensin converting enzyme (ACE) to angiotensin II Adrenal cortex: angiotensin II stimulates secretion of aldosterone (sodium retention) Ace inhibitors block production of angiotensin II ACE INHIBITORS: Aldosterone causes the block of ACE – treat high BP Inhibitor actions: Vasodilation Decrease in blood volume Promote excretion of Na and water Turns off RAAS system Glomerular filtration rate is the amount of filtrate produced in the kidneys each minute GFR depends on 2 autoregulatory mechanisms (myogenic and tubuloglomerular feedback) A drop in filtration pressure stimulates the release of hormones Renin stimulates adrenal production of aldosterone which can be blocked by ACE inhibitor URINARY PHYSIOLOGY REABSORPTION Return of filtered water and solutes to blood stream and approximately 99% of water is reabsorbed Intersitial fluid plays big role Proximal Convoluted tubule Reabsorption of water, ions, water soluble vitamins, glucose, amino acids Na, Ca, Cl, K, bicarbonate, urea and all organic nutrients Largest contribution. 2/3 filtrate is reabsorbed Solutes absorbed by passive/active transport H+ ions secreted into tubular fluid Simple cuboidal with micro villi Transport maximum (Tm) Passive and active mechanisms Transporter has upper limit (mg/min) Glucosuria: Blood glucose exceeds 200 mg/ml Some remain in urine, and this causes diabetes mellitus Genetic mutations in Na – glucose symporter reduce the Tm Excessive glucose in filtrate inhibits water reabsorption Nephron Loop: Descending loop: Reabsorption of water No solute movements Ascending loop: Reabsorption of Na, Cl, and K No water movement Solute concentration reduced High concentrations of waste Distal Convoluted Tubule: Adjustments to composition and concentration Impermeable to solutes (active reabsorption or secretion) Impermeable to water (requires ADH) Permeable to urea DCT and Collecting Duct ADH – concentrated urine (cells of DCT and CD are more permeable to water) Aldosterone increases reabsorption of Na and secretion of K ANH excretion of Na inhibits ADH and aldosterone release Tubular Secretion: K, H, ammonium ions Aldosterone targets DCT and CD cells Increases Na and K pump activity K goes into tubule Na goes out of tubule When blood pH decreases H+ increases (H+ secreted and bicarbonate ions reabsorbed) Osmolarity of filtrate changes through different regions of nephron until urine is formed REGULATING URINE CONCENTRATION: Concentrated urine forms when water is reabsorbed Release of ADH – water reabsorption (only when IF is more concentrated than filtrate Countercurrent mechanism creates and maintains medullary osmotic gradient Exchange material between filtrate, IF and blood a. countercurrent multiplier system (loop) b. recycling of urea (collecting duct) c. countercurrent exchanger (vasa recta) Countercurrent multiplier system: Fluid traveling in opposite directions Na K and Ca actively transported from filtrate into IF High solutes in IF draws water out of filtrate into IF Loss of water concentrates solutes in the filtrate as it approaches bottom of the loop High concentration of Na/K/Cl in filtrate approaching thick limb allows reabsorption to continue Recycling of urea: Medullary collecting system permeable to urea Water is reabsorbed, urea in filtrate more concentrated Urea passively diffuses out of filtrate and into If Further concentrates IF Some urea enters thin descending limb Much urea remains in filtrate and is excreted in urine Countercurrent exchanger Blood entering and leaving medulla has same concentration Critical for delivery of O2 and nutrients to medulla while maintain osmotic gradient Regulation of urine concentration: Only concentration gradient in IF drives osmosis 3 factors to create and maintain gradient As filtrate enters medullary collecting duct, with ADH, water is reabsorbed URINE COMPOSITION: Urine contains: Water, Na, K, Cl, H, phosphate, sulfates, metabolic wastes, and small amounts of bicarbonate, Ca, and Mg Renal clearance: measurement of rate at which kidneys remove a substance from blood Used to eliminate GFR (blood creatinine increases and clearance decreases) MICTURITION REFLEX: Stretch receptors in bladder wall stimulated Sensory impulses sent to the brain we become aware Motor impulses stimulate detrusor muscle to contract (sustains contraction) Contraction elevates fluid pressure Further increases volume Urine ejection when both internal and external sphincters relaxed 10mL of urine remains at the end of normal micturition External sphincters under voluntary control once relaxed internal sphincter relaxes Once volume exceeds 500mL, micturition reflex may force open internal sphincter causing reflexive relaxation of external sphincter Sensory fiber in pelvic nerve Parasympathetic preganglionic motor fiber in pelvic nerve Interneuron relays sensation to thalamus Postganglionic neuron in intramural gangion stimuates detrusor muscle concentration Projection fibers from thalamus deliver sensations to cerbral cortex Voluntary relaxation of external urethral sphincter causes relaxation of internal urethral sphincter Urination occurs URINARY INCONTINENCE Lack of voluntary control Infants and children under 2-3 years old: Normal – voiding occurs when bladder is distended Adult incontinence: Stress: weakness of deep muscles of pelvic floor Urge: abrupt, intense urge followed by involuntary urine loss Over flow: leakage f small amounts of urine Functional: unable to reach bathroom soon enough OVERVIEW: Filtration produces filtrate resembling blood plasma PCT reabsorbs 60-70% of water and almost all dissolved nutrients In PCT and descending limb water moves into surrounding interstitial fluid and then into peritubular capillaries Ascending limb is impermeable to water and solutes tubular cells actively pump Na and Cl out of tubular fluid urea remains Final composition and concentration determined by DCT and collecting ducts actively transported solutes under hormonal control Vasa recta maintains concentration gradient in medulla Urination is coordinated by micturition reflex WEEK 10 FLUID ELCTROLYTE AND ACID BASE HOMEOSTASIS Chemical bonds between some molecules permit dissociation. These compounds are called electrolytes. Dissociated particles are called ions. Compounds that do not dissociate are non-electrolyte (glucose) A BALANCE IMPLIES HOMEOSTASIS: Body “input” of water and electrolytes must be balanced by “output” Excess gain requires selective elimination and excess loss requires prompt replacement Fluid volumes remain relatively constant Imbalance: both total volume or amount of compartmental fluid is outside normal limits FLUID BALANCE: Fluid gained each day is equal to the amount lost ELECTROLYTE BALANCE Neither a net gain nor loss of any ion ACID BASE BALANCE Production of H+ ions is equal to their loss TOTAL BODY WATER Most of our body weight is water Age, fat, content, gender Muscle has a greater hold of water compared to adipose tissue As we age we do not take in as much sodium or water and loss more water than gain BODY FLUID COMPARTMENTS: ECF: Provides constant environment Transports substances ICF Facilitates intracellular chemical reactions RELATIVE VOLUMES: Intracellular volume – 25L Interstitial fluid – 12 L Plasma – 3 L EXTRACELLULAR VS. INTRACELLULAR FLUID Plasma and IF nearly identical chemically Plasma protein > IF protein Plasma contains more Na and few Cl ions than IF ECF ICF Most abundant cation Na K Most abundant anion Cl HPO4 Concentration of protein ions Few proteins Loss of protein SOURCES OF BODY WATER GAIN AND LOSS Water enters by: Water in foods Ingested liquids Tissue catabolism (ATP) Water exits by: Kidneys Lungs Skin Intestine Breathing/sweating/void *on average we loss 2500 mL REGULATING BODY WATER Fluid input = fluid output Imbalances occur when: More water enters/exits Total volume increases/decreases Primary goal of body is to adjust output to intake and secondary is to adjust intake Mechanisms rapid acting and maintain at expense of If volume Regulated water gain Regulated water loss Renin Angiotensin II osmoreceptors Aldosterone Dry mouth ANH REGULATING WATER: GAIN Volume of metabolic water depends on aerobic respiration Body water gain regulated by monitoring water intake Thirst centers in hypothalamus Dehydration = more water loss than water gain (this can lead to decreases BP) Fluid loss = decrease in blood volume When blood pressure falls renin is release and osmoreceptors are triggered Thirst sensations increase and fluid intake increase Normal fluid volume is restored REGULATING WATER: LOSS Sweating and exhalation Excess occurs by: control of urine volume Urinary salt loss determines blood volume How is urinary loss of ions regulated? - by hormones Increase NaCl intake Causes movement of water from intercellular to interstitial to plasma 3 hormones regulate Na and Cl reabsorption ADH regulates water loss Release is stimulated by decrease in blood volume Effects of ADH release: Stimulates thirst Insertion of water channels Water permeability increases WATER INTOXICATION Steady consumption of water This causes the cell to swell IV that is hypertonic would help REGULATION OF WATER AND ELCTROLYTES IN ECF Inside capillary: Blood hydrostatic pressure: fluid out of capillaries into If Blood colloid osmotic pressure: fluid from IF into capillaries Outside capillary: Interstitial fluid hydrostatic pressure: fluid out of IF into capillaries Interstitial fluid colloid osmotic pressure: fluid out of capillaries into IF Net movement = difference between opposing pressures Net movement = fluid out of capillaries – fluid into capillaries No net movement: (BHP + IFCOP) = (IFHP + BCOP) Fluid shift: (BHP + IFCOP) does not equal (IFHP + BCOP) Fluid out of capillary: (BHP + IFCOP) > (IFHP + BCOP) Fluid into capillary when: (BHP + IFCOP) < (IFHP + BCOP) HOMEOSTATIC FLUID IMBALANCES Edema: Abnormally large amounts of fluid in intercellular tissue spaces Pressure, aldosterone, proteins Pitting edema: Depression in swollen tissue Hypovolemia: Abnormally low blood volume Decrease in aldosterone Vigorous diuretic therapy REGULATION OF WATER AND ELCTROLYTES IN ICF Plasma membrane selectively permeable barrier Movement across membrane requires transport mechanisms Outside cell ECF there is more Na more Cl Inside cell ICF there is more K more phosphate and more protein Homeostasis: ECF and ICF similar osmolarity Solutions are isotonic Changes in ECF osmolarity result in fluid imbalance causing dehydration REGULATION OF SODIUM Major contributor to osmolarity of ECF (Cl also contributes) Changes effect compartment fluid volumes Controlled by aldosterone, ADH, ANH Hyponatremia: Na levels are low Overhydration, increase in ADH or a decrease in aldosterone Water moves into cell (swell) Hypernatremia: Sodium levels are high Dehydrated, increase aldosterone, increase dietary intake, kidney disease Water moves out of cell (crenation) REGULATION OF POTASSIUM major contributor to establishing membrane potential (essential for fcn of neurons, contraction of skeletal and cardiac muscle) Controlled by hormones (insulin, aldosterone) Hyperkalemia: K levels are high in blood Decrease excretion, increase dietary intake, drugs, shifts from ICF to ECF RMP more positive Hypokalemia: k levels low in blood Diuretics, vomiting, diarrhea, sweating RMP more negative (reduced excitability of neurons, hyperexcitability of cardiac muscles REGULATION OF CALCIUM: Mainly in ECF Hardiness of bone/teeth Blood clotting NT release Muscle contraction Calcitonin/PTH REGULATION OF CHLORIDE: Mainly ECF Easily moves between fluid compartments Helps balance anions (chloride shift) Reabsorbed with Na REGULATION OF PHOSPHATE Mainly ICF Hardiness of bone/teeth Buffer of H+ REGULATION OF BICARBONATE ION Mainly ECF Concentration increases as blood flow through capillaries Regulated by kidney Acid-base balance ACID BASE BALANCE Regulating H+ concentration on body fluids Mamy moleculescontain chemical groups that can either donate or accept a H= and behave as a weak acid or a weak base Challenge is to maintain homeostasis Slight changes affect ion channels, membrane receptors, enzymatic activities REVIEW OF pH CONCEPT # of H+/1L solution Expressed as 0-14 H+ increases, pH down = acidic (more H+ than base ions) H+ decreases, pH up = basic (more base ions than H+) PH of 7 = neutral (H+ = base ions) PH CONCEPT IN THE BODY Metabolic reactions = huge excess of H+ Removal of H+ depends on Buffer system: Temporarily bind H+ removing excess from solution Exhalation of CO2 Increase rate/depth of breaths to remove CO2 Kidney excretion of H+ Eliminates acids through excretion in urine THE ACTIONS OF BUFFER SYSTEMS Buffers convert strong acids and strong bases into weak acids and weak bases. When a strong base is added the weak acid donates its H+ When a strong acid is added the weak base accepts an H+ PROTEIN BUFFER SYSTEM In RBCs the buffer is hemoglobin In blood plasma the buffer is albumin Proteins have a carboxyl group (donates) and an amino group (accepts) PHOSPHATE BUFFER SYSTEM Regulating phosphate ions in ICF PH regulation in ECF Weak acid (dihydrogen phosphate) Weak base (monohydrogen phosphate) *when pH drops there is too much H+ *when pH rises there are too few H+ CARBONIC ACID BICARBONATE BUFFER SYSTEM: Bicarbonate ion synthesized and reabsorbed by kidneys When H+ in excess -> carbonic acid - > CO2 When there is a shortage of H+ formation of bicarbonate ion is favored MAINTAINING ACID BASE BALANCE: Captured H+ must ultimately be removed Respiratory and renal mechanisms: Secrete or absorb H+ Control excretion of acids and bases Generate more buffers Together chemical and physiological systems maintain pH EXHALATION OF CARBON DIOXIDE: Respiratory compensation: When pH exceeds normal limits PH altered by changing CO2 and H+ in plasma When respirations increase: CO2 levels decrease, H+ decrease and pH decreases When respiration rate decreases: CO2 levels increase H+ increase, and pH decreases EXHALATION OF CARBON DIOXIDE Relating respirations to pH: Decreases blood pH below normal Stimulates respirations – hyperventilation Prolonged hyperventilation May cause alkalosis Increase blood pH above normal Slows respirations – hypoventilation Prolonged hypoventilation May cause acidosis KIDNEY EXCRETION OF H+ Renal compensation: Changes in rates of H+ and bicarbonate ion secretion or absorption A decrease in blood pH results in the kidneys secreting more H+ and reabsorbing more making bicarbonate ion An increase in blood pH results in kidney tubules reabsorbing H+ and secreting bicarbonate ions ACID BASE IMBALANCES When buffering systems are severely stressed... Respiratory disorders from abnormal respiratory function Metabolic disorders from generating organic acids or by conditions affecting concentrations of bicarbonate ions ACIDOSIS: Metabolic acidosis = due to decrease in bicarbonate Respiratory acidosis = due to increase in carbonic acid ALKALOSIS: Metabolic alkalosis = due to increase in bicarbonate Respiratory alkalosis = due to decrease in carbonic acid RESPIRATORY ACIDOSIS: pH<7.35 The cause is increased CO2, inadequate exhalation, hypoventilation Treatment: Increased renal excretion of H+, and reabsorption of bicarbonate Bronchodilation Intravenous bicarbonate ions RESPIRATORY ALKALOSIS: pH > 7.45 High altitudes Decreases CO2 Hyperventilation Oxygen deficiency Treatment: Decreased renal excretion of H+ and reabsorption of bicarbonate Inhale/exhale into a bag METABOLIC ACIDOSIS: Large amounts of acids enter blood Blood levels of bicarbonate ion drop Impaired H+ excretion Treatment Hyperventilation Intravenous bicarbonate ion METABOLIC ALKALOSIS pH > 7.45 Elevated bicarbonate ion concentrations Reduction of H+ Prolonged vomiting, alkaline drugs Treatment: Hypoventilation Fluid solutions to correct for electrolytes *you are exercising at the gym building up lactic acid H+ levels go up *you have been vomiting for days losing stomach acid H+ levels go down AGING AND BALANCING ACTS: Decreased volume of ICF Compromised acid base balance Decreased GFR Reduced sensitivity to ADH Decrease in sweat glands Leading to: Dehydration (fluid) Hyper and hyponatremia (Na) Hypokalemia (K) Acidosis OVERVIEW: The pH of normal body fluids ranges from 7.35-7.45 If the pH varies outside of this range acidosis or alkalosis results Buffer system consists of a weak acid and weak base Amino acids components in protein buffer systems respond to changes in H+ Organic acids prevent changes in ECF through the carbonic acid bicarbonate buffer system Phosphate buffer system prevents pH changes in ICF Respiratory compensation raises/lowers PCO2 Renal compensation by kidneys involves varying H+ secretion and bicarbonate reabsorption WEEK 11 THE GENITAL SYSTEM SEXUAL REPORDUCTION Function: Ensure survival of genetic characteristics of a species Genital organs adapted for transferring genes to new generation of offspring Male genital system – organs produce, transfer, and introduce mature sperm into female genital tract where fertilization occurs Organs classified as essential for production of gametes or accessory which support reproductive process MALE GENITAL ORGANS Primary sex organs (gonads) testes External Gentelia: scrotum and penis Accessory organs: Genital ducts: epididymides, ductus deferens, ejaculatory ducts, urethra Accessory Glands: secretions that nourish transport, mature sperm: seminal vesicles, prostate, bulbourethral glands Supporting structures include the scrotum, spermatic cord and the penis TESTES Lobules composed of seminiferous tubules and interstitial cells Capsule – tunica albuginea Each testis in a supporting sac (the scrotum) Suspended by scrotal tissue and spermatic cord Fetal life: testes are in the abdominal cavity and descend into scrotum 2 months before birth undescended testes is known as cryptochism Tests require lower temps for sperm production Cryptochism: Corrected by testosterone or surgery Orchitis: Inflammation of the testes THE SCROTUM: Fleshy pouch suspends from perineum Scrotal cavities contain a testis, epididymis, part of a spermatic cord Thin layer of skin containing smooth muscle (dartos) Deeper cremaster muscle contracts pulling testes closer to the body when heat is required and if body temp rises cremaster relaxes TESTES FUNCTION: Spermatogenesis: In seminiferous and epididymis tubules – takes approximately 60-70 days It is stimulated by: FSH – follicle stimulating hormone (in seminipherous tubules) GnHR – gonadotropin releaseing hormone (anterior pituitary gland) STRUCTURE OF SPERMATOZOA Head covered by acrosome Hydrolytic enzymes released at capacitation (takes place in uterine tube) Break down cervical mucus, digest, penetrate outer covering of egg Mid piece contain mitochondria -> energy for locomotion tail (flagellum) - responsible for movement REGULATION OF SPERMATOGENESIS FSH binds Sertoli cells to promote spermatogenesis (guide the process) Nourish, support, protect spermatozoa Sertoli cells secrete inhibin (slows down how mush FSH is being made) Negative feedback loop to maintain normal sperm numbers TESTES FUNCTION Under influence of luteinizing H interstitial cells secrete (LH) (this tells interstitial cells to make testosterone) Testosterone: androgen Functions: Promotes primary and secondary sexual characteristics Protein anabolism Affects fluid/electrolyte balance GENITAL DUCTS EPIDIDYMIS Stores sperm – unused sperm breakdown Developed but not mature are in the epididymis one on each testicle and house/store spermatozoa for 2 weeks and mature First part of a ducting system and connects to the vas deferens Vasectomy: cutting/tying the vas deferens to disrupt the path GENITAL DUCTS VAS DEFERENS Excretory duct for seminal fluid 2 ducts one for each testicle and carry the spermatozoa from the epididymis and empty them into the first part of the urethra which is the prosthetic urethra Connect epididymis with ejaculatory duct Peristalsis propels sperm and fluid along length of duct 3 regions of the urethra Prostatic Membranous Spongy (penile) GENITAL DUCTS: EJACULATORY DUCT Joining the vas deferens and seminal vesicle Penetrates muscular wall of prostate gland, empties into the prostatic urethra ACCESSORY GLANDS Seminal vesicles (glands): Posterior of bladder Secretion is viscous alkaline (higher pH), nutrient rich (fructose) Contains vesiculase – prevents sperm from sticking together Prostate gland Encircles urethra just below bladder Secretion is slightly acidic, watery Contains seminalplasmin Flomax (tamsulosin) Alpha adrenergic blockers Relaxes muscles in prostate and bladder neck = easier to urinate (difficult to pee if the prostate enlarges) Bulbourethral glands: Below the prostate gland Duct connects to penile urethra Secretion is alkaline with mucus Size of pea Semen: 5% Rest is secretions from accessory glands Seminal vesicles 60% Prostate gland 30% Bulbourethral gland 5% COMPOSITION AND COURSE OF SEMINAL FLUID Consists of secretions from: Testes Epididymides Seminal vesicles Prostate Bulbourethral glands Each milliliter contains millions of sperms Passes from: Testes Epididymis Vas deferens Ejaculatory duct Urethra SUPPORTING STRUCTURE PENIS Consists of the root, body, and glans (the tip) Vascular channels, elastic connective tissue, smooth muscle Overlapping skin resembles scrotum Fold of skin (prepuce/foreskin) surrounds tip of penis Preputial glands: smegma (oily) 3 MASSES OF ERCTILE TISSUE: 2 CORPORA CAVERNOSA: Sponge like regions Contains most of blood during erection Center of each there is a central artery 1 CORPUS SPONGIOSUM Surround urethra, extends to tip of the penis forming glans Penis contains terminal duct for urinary and reproductive tracts During sexual arousal, penis becomes erect, serving as a copulatory organ NUERAL CONTROL OF THE SECUAL RESPONSE ERECTION: Parasympathetic reflex initiated by tactile, visual, mental stimuli Neurons innervating penile arteries release nitric oxide Vessels dilate = increased blood flow Dilation of arteries of penis floods distends spaces in erectile tissue Compresses veins Blood entering > leaving Penis becomes larger and rigid EMISSION: Refelx movment of spermatozoa and secretion of seminal fluid into prostatic urethra Once emission has occurred ejaculation will follow EJACULATION: Reflex response involves ejection of semen Increase heart rate, BP, hyperventilation, dilated blood vessels 3mL ejaculate = 300 million sperm FUNCTION OF FEMALE ASSIGNED GENITAL SYSTEM Produce offspring Produce effs (female gametes) Provide nutrition and protection to offspring after conception FEMALE ASSIGNED GENITAL ORGANS Primary sex organ: ovaries Acessory organs: uterine tubes, uterus, vagina Internal genitals: uterine tubes, uterus, vagina, ovaries External genitals: vulva Additional sex glands: mammary glands PERINEUM Skin covered region between vaginal orifice and rectum Urogenital triangle: external genitalia and urinary opening Anal triangle: surrounds anus Episiotomy: Incison in perineum to ease delivery OVARIES: Nodular glands Below and behind uterine tubes (fallopian tubes) Ovaries sit inferiors and slightly posterior to fallopian tubes Produce ova via oogenesis On 14th day of 28 day cycle LH causes ovulation Ova swept into uterine tube by fimbriae Under influence of LH remaining follicle reforms into corpus luteum Corpus luteum secretes more progesterone Prepares uterus for pregnancy and suppresses release of FSH = prevent follicle development No pregnancy: Corpus luteum degenerates into corpus albicans Progesterone levels fall causing monthly bleeding Pregnancy: Placenta of embryo secrete hCG (human chorionic gonadotropin) Maintains progesterone secretions for 3 months Maintains lining of endometrium HCG in blood or urine and that is the indicator of pregnancy Ovarian ligament: Anchors ovaries to uterus Broad ligament: Attaches posterior to ovary via mesovarian ligament Outer cortex: Germinal epithelium, 1000s of follicles At puberty FSH: follicle to enlarge and mature into a follicle As follicle grows estrogen secreted by follicle Approximately 400000 oocytes at puberty UTERINE TUBES 3 layers: Outer serous Middle smooth muscle Mucous membrane Layers continuous with uterus and vagina End closest to the ovary forms the infundibulum with numerous fimbriae Ciliated epithelium moves ovum toward uterus UTERUS: Pelvic cavity Body, cervix, fundus Body lies anteflexed over bladder Begins to decrease in size at menopause Cervix points downward, backward, joining vagina at a right angle 8 uterine ligaments these form a deep pouch – rectal uterine pouch of Douglas Wall: Endometrium (mucous), myometrium (smooth muscle), perimetrium (peritoneum) The cervix dips into the vagina producing anterior and posterior fornix (seminal fluid pools increasing chances of fertilization) Fertilization occurs in upper 1/3 of uterine tubes forming a zygote (further division and implants into endometrium) VAGINA: Locati

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