BIO302 Exam Study Guide PDF

Exam #2 study guide, Crash Courses: ​ Chapter 19: ​ ​ Blood, Part 1 - True Blood: Crash Course Anatomy & Physiology #29 ​ ​ Blood, Part 2 - There Will Be Blood: Crash Course Anatomy & Physiology #30 ​ Chapter 20: ​ ​ The Heart, Part 1 - Under Pressure: Crash...

Exam #2 study guide, Crash Courses: ​ Chapter 19: ​ ​ Blood, Part 1 - True Blood: Crash Course Anatomy & Physiology #29 ​ ​ Blood, Part 2 - There Will Be Blood: Crash Course Anatomy & Physiology #30 ​ Chapter 20: ​ ​ The Heart, Part 1 - Under Pressure: Crash Course Anatomy & Physiology #25 ​ ​ The Heart, Part 2 - Heart Throbs: Crash Course Anatomy & Physiology #26 ​ Chapter 21: Blood Vessels, Part 1 - Form and Function: Crash Course Anatomy & Physiology #27 ​ ​ Blood Vessels, Part 2: Crash Course Anatomy & Physiology #28 Faith’s Quizlet: A & P II: Exam 2 Flashcards | Quizlet Chapter 19 List the 7 ways blood helps to maintain homeostasis in the body. 1.​ Transport of gases, nutrients, and waste products a.​ E.g. oxygen 2.​ Transport of processed molecules a.​ Eg. precursor of vitamin D from skin to liver than kidneys 3.​ Transport of regulatory molecules 4.​ Regulation of pH and osmosis a.​ Normal pH of most body tissues is between 7.35 and 7.45 5.​ Maintenance of body temperature a.​ Eg. warm blood shunted to the interior of the body 6.​ Protection against foreign substances a.​ E.g. antibodies 7.​ Clot formation Name the components of blood plasma. ​ Plasma: the liquid part of blood (55% of the blood) ○​ Colloid: liquid containing suspended substances that don’t settle out of solution ​ Proteins (7% of plasma): ○​ Albumins: viscosity (thickness), osmotic pressure, buffer, transport of fatty acids, bilirubin, thyroid hormones ​ Most abundant (58% of plasma proteins) ○​ Globulins: transport lipids, carbohydrates, hormones, ions, antibodies, and complement ○​ Fibrogen: blood clotting ​ Least abundant (4% of plasma proteins) ​ Water (91% of plasma): acts as a solvent and suspending medium for blood components  ​ Ions (eg. electrolytes): involved in osmosis, membrane potentials, and acid-base balance ​ Nutrients: glucose, amino acids, triglycerides, cholesterol, vitamins ​ Waste products: ○​ Urea, uric acid, creatinine, ammonia salts ​ Breakdown products of protein metabolism ○​ Bilirubin: breakdown product of red blood cells ○​ Lactic acid: end product of anaerobic respiration ​ Gases: oxygen, carbon dioxide, and inert nitrogen ​ Regulatory Substances: hormones, enzymes List the three kinds of formed elements using both their common and technical names. 1.​ Red blood cells (erythrocytes): Biconcave discs, anucleate (no nucleus), contain hemoglobin a.​ Transports oxygen and carbon dioxide b.​ Most abundant formed element in the blood c.​ Die quickly because they lack a nucleus 2.​ White blood cells (leukocytes): protect body against microorganisms and remove dead cells and debris a.​ Granulocytes: cytoplasm contains large granules; have multi-lobed nuclei i.​ Three distinctive types: 1.​ Neutrophils 2.​ Eosinophils 3.​ Basophils b.​ Agranulocytes: cytoplasm contains small granules and nuclei that are not lobed i.​ Two distinctive types: 1.​ Lymphocytes 2.​ Monocytes 3.​ Platelets (thrombocytes): cell fragment a.​ Form platelet plugs, release chemicals necessary for blood clotting (coagulation) b.​ Carry growth factors Describe the structure and function of hemoglobin, and relate which gases associate with hemoglobin and how. ​ Types of hemoglobin ○​ Embryonic and fetal: have a greater attraction for oxygen than adult. Fetal production stops after birth ○​ Adult ​ Oxyhemoglobin: transporting oxygen ​ Deoxyhemoglobin: looking to grab something ​ Carbaminohemoglobin: transporting carbon dioxide ​ RBC Function: Transport ○​ Oxygen from lungs to tissues: 98.5% attached to hemoglobin ​ 1.5% dissolved in plasma ○​ Carbon dioxide from tissues to lungs ​ 7% dissolved in plasma ​ 23% in combination with hemoglobin ​ 70% transported as bicarbonate ions produced as a result of combination of H2O and CO2 because of enzyme: Carbonic Anhydrase found within RBC ​ CO2 + H2O ↔ H2CO3 ↔ H+ +HCO3- ​ Hemoglobin composition: ○​ Four globin molecules (polypeptide chains): transport carbon dioxide and nitric oxide  ​ NO brought from lungs to tissues induces smooth muscles to relax, lowering BP ○​ Four Heme molecules: transport oxygen ​ Each contain one iron atom ○​ Iron required for oxygen transport. Iron absorbed in upper small intestine, increased by stomach acid and vitamin C. Iron lost in urine, feces, menstrual fluid Discuss the life history of red blood cells. ​ Erythropoiesis* ○​ Erythropoietin: ​ Hormone produced mostly by the kidneys ​ Secretion increases when blood oxygen levels are low. This stimulates red bone marrow to produce more red blood cells. This allows the blood to transport more oxygen ​ Hematopoiesis or hemopoiesis: process of blood cell production ​ Stem cells (hemocytoblast): all formed elements derived from single population ○​ Proerythroblasts: Develop into red blood cells ○​ Myeloblasts: Develop into basophils, neutrophils, eosinophils ○​ Lymphoblasts: Develop into lymphocytes ○​ Monobalsts: Develop into monocytes ○​ Megakaryobalsts: Develop into platelets ​ Red blood cells: ○​ Production of red blood cells (need B12, folic acid, iron): ​ Stem cells > proerythroblasts > early erythroblasts > intermediate erythroblasts > late erythroblasts > reticulocytes ○​ found in higher concentration in male than in female ​ Because of testosterone ○​ Reticulocyte: immature RBC; when a red blood cell first leaves the bone marrow and enters the bloodstream  ○​ Components ​ ⅓ hemoglobin ​ ⅔ lipids, ATP, carbonic anhydrase Compare the structures and functions of the five types of white blood cells (leukocytes). 1.​ Neutrophils: “first line of defense” a.​ after leaving bone marrow, stay in circulation 10-12 hours then move to other tissues b.​ Become motile, phagocytize bacteria, antigen-antibody complexes and other foreign matter c.​ Secret lysozyme d.​ Last 1-2 days e.​ Account for 60-70% of the WBC (majority of WBCs) 2.​ Eosinophils: a.​ Leave circulation and enter tissues during inflammatory response b.​ Prevalent in allergic reactions c.​ Destroy inflammatory chemicals like histamine d.​ Release chemicals that help destroy tapeworms, flukes, pinworms, and hookworms e.​ Account for 2-4% of the WBC 3.​ Basophils:  a.​Least common b.​Leave circulation and migrate through tissues c.​Play a role in both inflammatory response and allergic reactions d.​Produce histamine and heparin i.​ Heparin: blood thinning agent e.​ Account for less than 1% of the WBC 4.​ Lymphocytes: a.​ Produced in red bone marrow but then migrate to lymphatic tissues and proliferate b.​ Responsible for antibody production* c.​ Studied extensively with the immune system d.​ Account for 20-25% of the WBC 5.​ Monocytes: a.​ Remain in circulation for 3 days, leave circulation to become macrophages* b.​ Phagocytic cells c.​ Can break down antigens and present them to lymphocytes for recognition d.​ Account for 3-8% of the WBC *Know what they look like Describe the origin and structure of platelets. ​ Cell fragments pinched off from megakaryocytes in red bone marrow ○​ Fragments of larger stem cells ​ Surface glycoproteins and proteins allow adhesion to other molecules; ie. collagen ​ Important in preventing blood loss ○​ Platelet plugs ○​ Promoting formation and contraction of clots Relate the functions of platelets in preventing blood loss. ​ Hemostasis: arrest of bleeding ​ 3 stages of preventing excessive blood loss 1.​ Vascular spasm: vasoconstriction of damaged blood vessels - “pinch off” a.​ Can occlude small vessels b.​ Caused by thromboxanes from platelets and endothelin from damaged endothelial cells 2.​ Platelet plug formation 3.​ Coagulation or blood clotting - Two pathways: extrinsic & intrinsic a.​ Fibrin fibers (fibrinogen) b.​ Clotting requires vitamin K  c.​ Thrombus: a blood clot attached to a blood vessel wall d.​ Embolus: a thrombus which has broken off and is in the bloodstream Explain the basis of the ABO blood group system and how incompatibilities occur. ​ Blood grouping is determined by antigens (agglutinogens) on the surface of RBCs ○​ Antibodies (agglutinins) can bind to RBC antigens, resulting in agglutination (clumping) or hemolysis (rupture) of RBCs Describe the Rh blood group and its connection to hemolytic disease of the newborn (HDN). ​ Types: ○​ Rh positive: have Rh antigens present on surface of RBCs ​ Do not have Rh antibodies ○​ Rh negative: do not have Rh antigens present ​ Have Rh antibodies ​ Hemolytic disease of the newborn ○​ Rh positive fetus, Rh negative mother ○​ Late in pregnancy, Rh antigens of fetus cross placenta (through a tear in placenta or during delivery); mother creates antiRh antibodies (primary response) ○​ In a second Rh positive pregnancy might initiate secondary response and HDN (potentially fatal to fetus since antibodies to its RBCs would cross the placenta from the mother to the fetus, destroying fetal RBCs) ○​ Injection of RhoGAM. Contains antibodies against Rh antigens. Antibodies attach to any fetal RBCs and they are destroyed Define: Plasma: the liquid part of blood Erythropoiesis: RBCs last 120 days in circulation (enucleated) Proerythroblast: develop into red blood cells Megakaryoblast: develop into platelets Bilirubin: breakdown product of RBCs that is unable to be recycled; waste product *Chemotaxis: attraction to and movement toward foreign materials or damaged cells (WBCs) ​ Eg. histamine and inflammation ​ Accumulation of dead white cells and bacteria is pus Diapedesis: cells become thin, elongate and move either between or through endothelial cells of capillaries Thrombus: a blood clot attached to a blood vessel wall Embolus: a thrombus which has broken off and is in the bloodstream Agglutination: clumping of red blood cells ​ Caused by: a bad transfusion - antibodies, bind to antigens Antigen: protein identifiers; “flags” identifies if the molecule belongs to the body - calls out to the antibodies. Antibody: marks foreign antigens for destruction by WBCs Reticulocyte: immature RBC; when a red blood cell first leaves the bone marrow and enters the bloodstream Chapter 20 ​ Apex: bottom of the heart ​ Base: top of the heart ​ Red: oxygenated ​ Blue deoxygenated List the major functions of the heart. 1.​ Generating blood pressure 2.​ Routing blood: separates into pulmonary and systemic circulations a.​ Pulmonary: through the lungs; right side of the heart i.​ Blood entering: oxygenated ii.​ Blood exiting: deoxygenated b.​ Systemic: through the body; left side of the heart  i.​ Blood entering: deoxygenated ii.​ Blood exiting: oxygenated 3.​ Ensuring one-way blood flow: valves 4.​ Regulating blood supply a.​ Changes in contraction rate and force match blood delivery to changing metabolic rates List the layers of the heart wall, and describe the structure and function of each. ​ Pericardium or pericardial sac ○​ Fibrous pericardium: tough, fibrous outer layer. Prevents over distention (inflation); acts as anchor ○​ Serous pericardium: thin, transparent, inner layer. Simple squamous epithelium ​ Parietal pericardium: lines the fibrous outer layer ​ Visceral pericardium (epicardium): covers heart surface ​ The two are continuous and have a pericardial cavity with pericardial fluid ​ Prevents friction ​ Heart Wall: ○​ Epicardium (visceral pericardium): serous membrane; smooth outer surface of the heart ○​ Myocardium: middle layer composed of cardiac muscle cell and responsibility for heart contracting ○​ Endocardium: smooth inner surface of heart chambers ○​ Pectinate Muscle: muscle ridges in auricles and right atrial wall ○​ Trabeculae Carnae: muscular ridges and columns on the inside walls of ventricles Relate the large veins and arteries that enter and exit the heart. ​ Arteries: away from the heart ○​ Right coronary artery: exits aorta just superior to point where aorta exits heart ​ Lies in the coronary sulcus. Smaller than left. Extends to posterior aspect of heart ​ Right marginal artery to lateral wall of right ventricle ​ Posterior interventricular artery: lies in posterior interventricular sulcus, supplies posterior and inferior aspects of heart ○​ Left coronary artery: exits aorta near right coronary ​ Branches: ​ Left anterior descending artery in anterior interventricular sulcus ​ Left marginal artery supplies lateral wall of left ventricle ​ Circumflex artery extends to posterior aspect  ​ Veins: toward the heart ○​ Great cardiac vein and small cardiac vein drain right margin of heart ○​ Coronary sinus: veins empty here then into the right atrium ○​ Number of small veins drain the rest of the heart Review the structure and functions of the chambers of the heart. ​ Atria ○​ Right atrium: Three major opening to receive blood returning from the body ​ Superior vena cava ​ Inferior vena cava ​ Coronary sinus* ○​ Interatrial septum: wall between the atria, contains a depression, the foramen ovale, a remnant of the fetal opening between the atria ○​ Left atrium: four openings receive blood from the pulmonary veins  ​ From the lungs ​ Ventricles ○​ Right ventricle: opens to the pulmonary trunk ○​ Left ventricle: opens to aorta ○​ Atrioventricular canals: openings between atria and respective ventricles ○​ Interventricular septum: between the two ventricles Name the valves of the heart, and state their locations and functions. ​ Atrioventricular valves (AV valves) ○​ Each valve has leaf-like cusps that are attached to cone-shaped papillary muscle by tendons (chordae tendineae). ○​ Right has three cusps (tricuspid). ○​ Left has two cusps (bicuspid, mitral). ○​ When valve is open, canal is atrioventricular ​ Semilunar valve. ○​ Right (pulmonary- lungs) ○​ Left (aortic) ○​ Each cusp is shaped like a cup ○​ When cusps are filled, valve is closed; when cusps are empty, valve is open Relate the flow of blood through the heart, naming the chambers, valves, and vessels in the correct order. 1.​ Period of isovolumetric Contraction (systole) 2.​ Period Of Ejection (systole) ○​ Pressure in the ventricles has increased to the point where it is greater than the pressure in the pulmonary trunk/aorta. Pushes the cusps of the semilunar valves against the walls of the vessels, opening the valve ○​ Blood is ejected from the ventricles  ○​ The pressures in the two ventricles are different: 120 mm Hg in the left ventricle; 25 mm Hg in the right ventricle. ​ **Blood in left ventricle must be pumped to whole body ​ **Blood in the right ventricles is pumped to the lungs 3.​ Period of Isovolumetric Relaxation (diastole) 4.​ Passive Ventricular Filling (diastole) 5.​ Active ventricular filling (diastole) Relate the structural and functional characteristics of cardiac muscle cells. ​ Has a plato phase due to calcium  ​ Elongated, branching cells containing 1-2 centrally located nuclei ​ Contains actin and myosin myofilaments ​ Intercalated disks: specialized cell-cell contacts ○​ Cell membranes interdigitate; desmosomes hold cells together ○​ Gap junctions allow action potentials to move from cell to cell ○​ Connects all the cells together ​ Electrically, cardiac muscle of the atria and ventricles behaves as single unit Explain the structure and function of the conducting system of the heart. ​ SA node (“pacemaker of the heart”): sinoatrial node ○​ Medial to opening of superior vena cava ○​ The pacemaker ○​ Specialized cardiac muscle cells ○​ Generate spontaneous action potentials ○​ Action potentials pass to atrial muscle cells and to the AV node ​ AV node: atrioventricular node ○​ Medial to the right atrioventricular valve ○​ Action potentials conducted more slowly here than in any other part of system ○​ Ensures ventricles receive signal to contract after atria have contracted ​ AV bundle: passes through hole in cardiac skeleton to reach interventricular septum ​ Right and left bundle branches: extend beneath endocardium to apices of right and left ventricles ​ Purkinje fibers: large diameter cardiac muscle cells with few myofibrils; many gap junctions; conduct action potential to ventricular muscle cells Explain the importance of a long refractory period in cardiac muscle. ​ Important because of calcium (plateau phase) ○​ Long Refractory period prevents tetanic contractions ​ Absolute: Cardiac muscle cell completely insensitive to further stimulation ​ Relative: Cell exhibits reduced sensitivity to additional stimulation Describe the waves and intervals of an electrocardiogram. ​ Electrocardiogram: record of electrical events in the myocardium that can be correlated with mechanical events ​ P wave: depolarization of atrial myocardium and signals the onset of atrial contraction (muscle is contracting) ​ QRS complex: ventricular depolarization and signals onset of ventricular contraction. Repolarization of atria simultaneously ○​ Ventricles contracts and the atria relax simultaneously ​ T wave: repolarization of ventricles; precedes ventricular relaxation (muscle goes back to relaxed) ​ PQ interval or PR interval: 0.16 sec; atria contract and begin to relax, ventricles begin to contract ​ QT interval: 0.36 sec; ventricles contract and begin to relax Discuss the heart sounds and their significance. ​ First Heart Sound or “lubb” ○​ Atrioventricular valves and surrounding fluid vibrations as valves close at beginning or ventricular systole  ​ Second heart sound or “dubb” ○​ Results from closure of aortic and pulmonary semilunar valves at the beginning of ventricular diastole, lasts longer ​ Third heart sound (occasional) ○​ Caused by turbulent blood flow into the ventricles and detected near end of first one-third of diastole Define mean arterial pressure. ​ Average blood pressure in aorta ○​ Blood pressure measurement taken in the arm is a reflection of aortic pressures, not ventricular ​ MAP = Cardiac Output x Peripheral Resistance ○​ CO is amount of blood pumped by heart per minute ​ CO = SV x HR ​ SV: stroke volume (blood pumped during each heartbeat) ​ HR: Heart rate (number of times the heart beats per minute) ​ Cardiac reserve: Difference between CO at rest and maximum CO ○​ PR is total resistance against which blood must be pumped ​ Affected by blood pressure, size of the lumen in the vessels ​ Factors affecting MAP (increase MAP) ○​ Decreased blood pressure, decreased blood pH, increased blood CO2, decreased blood oxygen, exercise, and emotions ​ Results in increased heart rate ​ Which leads to increased cardiac volume ○​ Increased blood volume, exercise, change from standing to a lying down position ​ Results in increased stroke volume ​ Which leads to increased cardiac output ○​ Decreased blood pressure, decreased blood pH, increased blood carbon dioxide, and decreased blood oxygen ​ Increased vasoconstriction ​ Increased peripheral resistance Relate the three types of extrinsic regulation of the heart and their effects. ​ Extrinsic Regulation: involves neural and hormonal control ○​ Parasympathetic stimulation ​ Supplied by vagus nerve, decreases heart rate, acetylcholine is secreted and hyperpolarizes the heart ○​ Sympathetic stimulation ​ Supplied by cardiac nerves. Innervate the SA and AV nodes, coronary vessels and the atrial and ventricular myocardium. Increases heart rate and force of contraction. Epinephrine and norepinephrine released ​ Increased heart beat causes increased cardiac output. Increased force of contraction causes a lower end systolic volume; heart empties to a greater extent. limitation : heart has to have time to fill  ○​ Hormonal Control: Epinephrine and norepinephrine from the adrenal medulla. Occurs in response to increased physical activity, emotional excitement, stress. Explain how body temperature affects the function of the heart. ​ Heart rate increases when body temperature increases ​ Heart rate decreases when body temperature decreases Define: Pulmonary circuit: Through the lungs systemic circuit: through the body pectinate muscle: muscular ridges in auricles and right atrial wall; atrium only Papillary muscle: muscular ridges in ventricles only; attach to valves Trabeculae carne: muscular ridges and columns on the inside walls of ventricles (think bone trabeculae) Chordae tendineae: tendons attach from the papillary muscles to the valves Coronary sinus: veins empty here then into the right atrium Angioplasty: surgery that expands a blood vessel where the blood is beginning to clot; (uses a catheter) Intercalated disc: specialized cell-cell contacts Purkinje fibers: large diameter cardiac muscle cells with few myofibrils; many gap junctions; conduct action potential to ventricular muscle cells Tetanic contraction: complete muscle contraction Dicrotic notch: when the aortic semilunar valve closes, pressure within the aorta increases slightly Baroreceptor: monitor blood pressure; in walls of internal carotids and aorta. This sensory information goes to centers in the medulla oblongata Semilunar valves: Right (pulmonary- lungs), Left (aortic); Each cusp is shaped like a cup; When cusps are filled, valve is closed; when cusps are empty, valve is open Systole: repetitive contraction of the heart chambers Diastole: repetitive relaxation of the heart chambers Intrinsic regulation: results from normal functional characteristics, not on neural or hormonal regulation Chapter 21 List the types of capillaries, arteries, and veins in order starting from the heart to the tissues, back to the heart. 1.​ Heart 2.​ Elastic artery 3.​ Muscular artery 4.​ Arteriole 5.​ Metarteriole 6.​ Capillary 7.​ Venule 8.​ Small vein 9.​ Medium/large veins 10.​ Heart Describe the structure and function of capillaries, arteries, and veins. ​ Capillaries: site of exchange within tissue ○​ Wall consists of endothelial cells (simple squamous epithelium), basement membrane and a delicate layer of loose C.T. ​ Scattered pericapillary cells that are fibroblasts, macrophages, or undifferentiated smooth muscle cells are also present ○​ Substances move through capillaries by diffusion ​ Lipid-soluble and small water-soluble molecules through the plasma membrane. Barrier to proteins. ​ Larger water-soluble molecules pass through fenestrae or gaps between endothelial cells ​ Need to be resistant to proteins ○​ Types: ○​ Continuous capillary: less permeable to large molecules; muscle and nerve tissue ​ Eg. blood-brain barrier ○​ Fenestrated (gaps) capillary: highly permeable; intestinal villi, ciliary process of eye, choroid plexus, glomeruli of kidney ○​ Sinusoidal capillary: large diameter with large fenestrae; endocrine glands ○​ Sinusoids: larger; liver, bone marrow ○​ Venous sinuses: even larger; spleen ○​ Capillary Network: ​ Blood flows from arterioles through metarterioles, then through capillary network ​ Flow through thoroughfare channel fairly consistent while flow through arterial capillaries is intermittent ​ Smooth muscle in arterioles, metarterioles, and precapillary sphincters regulates blood flow  ​ Portal veins: begin in a primary capillary network, extend some distance and end in a secondary capillary network without a pumping mechanism, such as the heart, in between ​ Arteries & veins: * ○​ Layers from center out: ​ Tunica intima: ​ Endothelium ​ Basement membrane ​ Lamina propria (C.T. layer) ​ Internal elastic membrane. Fenestrated layer of elastic fibers ​ Tunica media: smooth muscle cells arranged circularly around the blood vessel ​ Vasoconstriction: smooth muscles contract, decrease in blood flow ​ Vasodilation: smooth muscles relax, increase in blood flow ​ Tunica externa (adventitia): connective tissue, varies from dense regular near the vessel to loose that merges with the surrounding C.T. ○​ Arteries - more elastic, Veins - can stretch, but not very elastic ​ Arteries: (mostly need to know order, not specifics) ○​ Elastic or conducting arteries: ​ Largest diameters, pressure high and fluctuates between systolic and diastolic. More elastic tissue than muscle. ​ Relatively thick tunica intima, thin tunica media ○​ Muscular or medium arteries: ​ Smooth muscle allows vessels to regulate blood supply by constricting or dilating ​ Most of the smaller unnamed arteries ​ Thick walls due to 25-40 layers of smooth muscle ​ Also called distributing arteries because smooth muscle allows vessels to partially regulate blood supply to different regions of the body  ○​ Arterioles ​ Transport blood from small arteries to capillaries ​ Smallest arteries where the three tunics can be differentiated ​ Like small arteries, capable of vasoconstriction and dilation ​ Veins: thinner walls than arteries, contain less elastic tissue and fewer smooth smooth muscle cells ○​ Venules: ​ Drain capillary network. ​ Endothelial cells and basement membrane with a few smooth muscle cells. ​ As diameter of venules increases, amount of smooth muscle increases ○​ Small veins: ​ Smooth muscle cells form a continuous layer ​ Addition of tunica adventitia made of collagenous connective tissue ○​ Medium veins: go between small veins and large veins ○​ Large veins ​ Tunica intima is thin: endothelial cells, relatively thin layer of C.T. and a few scattered elastic fibers. ​ Tunica media has circularly arranged smooth muscle cells ​ Adventitia is predominant layer ​ Valves found in all veins greater than 2mm in diameter ○​ Folds in intima form two flaps that overlap ○​ More valves in veins of lower extremities than in veins of upper extremities ○​ Varicose veins: the valves in the veins break down Describe the innervation of the blood vessel walls. ​ Unmyelinated sympathetic nerve fibers form plexi in tunica adventitia: vasoconstriction  ​ Small arteries and arterioles innervated to greatest extent ​ Vessels of penis and clitoris innervated by parasympathetic ○​ Only vessels that are innervated by parasympathetic nerves ​ Some blood vessels innervated by myelinated fibers and act as baroreceptors that monitor stretch and detect changes in blood pressure Discuss age-related changes to blood vessels. Atherosclerosis vs arteriosclerosis. ​ Arteriosclerosis: general term for degeneration changes in arteries - thickened tunica intima less elastic tunica media ○​ Do not stretch or go back to original shape as easily ○​ Hardening of the arteries ​ Atherosclerosis: deposition of plaque on walls ​ Blood pressure rises List the major arteries that supply head and upper extremity. Head: ​ Common carotid ​ Carotid sinus ​ Internal carotid ​ External carotid Upper limb ​ Lt. Subclavian ​ Lt. Axillary ​ Lt. Brachial ​ Brachiocephalic ​ Subclavian ​ Axillary ​ Brachial ​ Radial ​ Ulnar Define blood pressure. Describe how it is measured. ​ Blood Pressure: Measure of force exerted by blood against the wall ​ Blood moves through vessels due to blood pressure ​ Measured by listening for Korotkoff sounds produced by turbulent flow in arteries as pressure released from blood pressure cuff. Describe the relationship of viscosity to blood flow. ​ Measure of resistance of liquid to flow ​ Resistance proportional to flow ​ As viscosity increases, pressure required to flow increases ​ Viscosity influenced largely by hematocrit (percentage of the total blood volume composed of red blood cells)** ​ Dehydration and/or uncontrolled production of RBCs can lead to increased viscosity which increases the workload on the heart. Relate Laplace’s law to critical closing pressure. ​ Critical closing pressure: pressure at which a blood vessel collapses and blood flow stops ​ Force acting on blood vessel wall is proportional to diameter of the vessel times blood pressure ​ F=DxP; as the diameter of a vessel increases, force on the wall increases. Weakened part of a vessel wall bulges out and is an aneurysm. Define pulse pressure and list locations on the body where the pulse can be detected. ​ Difference between systolic and diastolic pressures ​ Increases when stroke volume increases or vascular compliance decreases. Compliance tends to decrease with age (arteriosclerosis) and pressure rises. ​ Pulse pressure can be used to take a pulse to determine heart rate and rhythmicity  ​ Most frequent site used to measure pulse rate is in the carpus with the radial artery- the radial pulse. Describe the exchange of materials across a capillary wall. ​ Capillary Exchange: the movement of substance into and out of capillaries ​ Most important means of exchange: diffusion ○​ Lipid soluble cross capillary walls diffusing through plasma membrane. ​ E.g. O2, CO2, steroids hormones, fatty acids ○​ Water soluble diffuse through intercellular spaces or through fenestrations of capillaries ​ E.g. glucose, amino acids ​ Blood pressure, capillary permeability, and osmosis affect movement of fluid from capillaries ​ Fluid moves out of capillaries at arterial end and most but not all returns to capillaries at arterial end and most but not all returns to capillaries at venous end. That which remain in tissues is picked up by the lymphatic system then returned to venous circulation ​ Chemicals of inflammation increase permeability-burns ​ If capillaries become more permeable, proteins can leak into the interstitial fluid increasing ICOP (interstitial colloid osmotic pressure)-interstitial colloid osmotic pressure.  ○​ Edema: more fluid moves from the capillaries into the interstitial fluid ○​ Chemicals of inflammation increase permeability-burns2 ○​ Decrease in plasma concentration of protein reduces BCOP-blood colloid osmotic pressure; more fluid moves into interstitial fluid: ​ Liver disease resulting in fewer plasma proteins ​ Loss of plasma proteins through the kidneys ​ Protein starvation ○​ Blockage of veins increases capillary BP; reduced venous return due to gravity ○​ Blockage or removal of lymphatic vessels Explain how preload, venous tone, and gravity affect cardiac output. ​ Venous return to heart increases due to increase in blood volume, venus tone, and arteriole dilation ​ Venous tone: continual state of partial contraction of the veins as a result of sympathetic stimulation ​ Gravity ○​ In a standing position, hydrostatic pressure caused by gravity ​ increases blood pressure below the heart ​ decreases blood pressure above the heart ○​ Muscular movement improves venous return Explain how local mechanisms regulate blood flow. ​ Local control of blood flow is achieved by the periodic relaxation and contraction of precapillary sphincters regulating blood flow through the tissues. ○​ In most tissues, blood flow is proportional to the metabolic needs of the tissue ○​ Blood flow also increases in response to a buildup of metabolic end products Explain how nervous and hormonal mechanisms control blood flow. Neural Control: ​ Important in minute-to-minute regulation of local circulation ​ Provides a means by which blood can be shunted from one large area of the peripheral circulatory system to another area by increasing resistance ​ Sympathetic division most important innervates all vessels except capillaries, precapillary sphincters and most metarterioles. ​ Vasomotor center in lower pons and upper medulla oblongata ○​ Excitatory part is tonically active - norepinephrine ○​ Inhibitory part can cause vasodilation by decreasing sympathetic output ​ Sympathetic stimulation of adrenal medulla causes output of norepinephrine and epinephrine into circulation. Causes vasoconstriction in vessels expect in skeletal muscles where vasodilation takes place Relate the factors that determine mean arterial pressure. MAP = CO (Cardiac output) x PR (peripheral resistance) CO = HR (heart rate) x SV (stroke volume) ​ An increase in any of these elevates blood pressure, a decreases reduces blood pressure ○​ Eg. an increase in blood volume increases venous return, which increases preload, and the increased preload increases stroke volume Describe the short-term and the long-term mechanisms that regulate arterial pressure. Long term: ​ Atrial natriuretic hormone: released from cardiac muscle cells when atrial blood pressure increases, stimulating an increase in urinary production, causing a decrease in blood volume and blood pressure ​ Fluid Shift: movement of fluid from the interstitial spaces into capillaries in response to decrease in blood pressure to maintain blood volume and vice versa ​ Stress-relaxation response: adjustment of blood vessel smooth muscle to respond to change in blood volume. When blood volume suddenly declines and pressure drops, smooth muscles contract and vice versa. Short Term: ​ Baroreceptor reflexes: change peripheral resistance, heart rate, and stroke volume in response to changes in blood pressure ​ Chemprectpor reflexes: sensory receptors sensitive to oxygen, carbon dioxide, and pH levels of blood ​ Central Nervous system ischemic response: results from high carbon dioxide or low pH levels in medulla and increases peripheral resistance Define: Endothelium: simple squamous epithelial cells that make up the inner layer of blood vessels precapillary sphincter: regulates blood flow vasa vasorum: blood vessels that supply the walls of arteries and veins. Penetrate vessel walls from the exterior. Branches of arteries great saphenous vein: longest vein in the body hepatic portal system: blood entering the hepatic portal vein is rich with nutrients collected from the intestines, but may also contain toxic substances. Both nutrients and toxic substances will be regulated by the liver. systole: diastole: Korotkoff sounds: produced by turbulent flow in arteries as pressure released from blood pressure cuff critical closing pressure: pressure at which a blood vessel collapses and blood flow stops Edema:if capillaries become more permeable, proteins can leak into the interstitial fluid increasing ICOP-interstitial colloid osmotic pressure. More fluid moves from the capillaries into the interstitial fluid Hematocrit: percentage of the total blood volume composed of red blood cells Angiotensin II: potent vasoconstrictor, results in increased blood pressure Vasopressin: antidiuretic hormone; increases the kidney’s reabsorption of water; increases blood volume and blood pressure aldosterone: acts on kidneys to increase Na+ reabsorption. As a result, urine volume decreases and blood volume increases, causing blood pressure to rise atrial natriuretic hormone: released from cardiac muscle cells when arterial blood pressure increases, stimulating an increase in urinary production, causing a decrease in blood volume and blood pressure