Physio Exam 3 Study Guide PDF

Functions of the Endocrine System: Controls and coordinates body’s response to changes in environment using hormones Performs bodily regulation using glands and hormones Major Glands of the Endocrine System: 1. Hypothalamus: maintains the body’s homeostasis and regulates temperature, hea...

Functions of the Endocrine System: Controls and coordinates body’s response to changes in environment using hormones Performs bodily regulation using glands and hormones Major Glands of the Endocrine System: 1. Hypothalamus: maintains the body’s homeostasis and regulates temperature, heart rate, and blood pressure. 2. Pituitary Gland: Made of 2 lobes: anterior and posterior →Anterior: secretes hormones used for body’s growth and development →Posterior: secretes hormones that increase reabsorption of water into the kidneys 3. Pineal Gland: Produces melatonin (used for sleep-wake cycle) 4. Thyroid Gland: produces 3 major hormones: Calcitonin, Triiodothyronine, and Thyroxine →All 3 regulate body’s energy and metabolism 5. Parathyroid Gland: secretes hormones needed for calcium absorption 6. Thymus: controls production of white blood cells (T-cells) and allows for body to fight diseases 7. Ovaries & Testes: release hormones responsible for blood circulation, mental vigor, and sex drive →Ovaries: secretes estrogen & progesterone needed for health of female reproductive system →Testes: secretes testosterone needed for physical development, bone density, and libido 8. Pancreas: Aids in digestion of proteins, fats, and carbohydrates. Produces insulin and glucagon which regulate glucose level in blood 9. Adrenal Gland: Produces adrenaline & cortisol that allow the body to respond to stress What Happens When the 3 Hormones Bind to Their Receptors? 1. Protein Hormones (Peptide Hormones) bind to Receptor Proteins on the Cell Membrane Surface →the binding of the hormone triggers chemical reactions created by chemicals called second messengers, which are small molecules that send signals throughout the cytoplasm & cell →2 most common second messengers are calcium ions (C2+) and cyclic AMP (cAMP) →second messengers activate and inactivate enzymes →composed of long chains of amino acids (difference between amino acid derived hormones) 2. Steroid (Lipid) Hormones Bind to Receptor Proteins in the Cytoplasm or inside nucleus of target cells →all steroid hormones are derived from cholesterol →When they enter the cell, they bind to intracellular receptors to form a “hormone-receptor complex.” →This complex acts as a transcription factor, binding to specific DNA sequences to promote or inhibit transcription, which subsequently affects protein synthesis (translation). 3. Amino Acid (Protein) Derived Hormones bind to Cell Surface Membrane Receptors → These hormones are derived from modifications of single tyrosine or tryptophan molecules →Upon binding to the receptor, the receptor activates secondary proteins or enzymes in the membrane, such as G-proteins.  →This activates a second (and sometimes third) messenger system (e.g., cAMP or calcium ions), which triggers a cellular response in the cytoplasm. All the Pituitary Hormones: Posterior pituitary releases 2 peptide hormones: 1. Oxytocin 2. Vasopressin (aka antidiuretic hormone, ADH) Anterior Pituitary releases 6 hormones: 1. Prolactin (PRL) 2. Thyrotropin (TSH) 3. Adrenocorticotropin (ACTH) 4. Growth Hormone (GH) 5. Follicle-stimulating hormone (FSH) 6. Luteinizing hormone (LH) Hormone Interaction: 1. Synergism: occurs when 2 or more hormones produce the same effects in a target cell and the results are amplified 2. Permissiveness: occurs when a hormone cannot exert its full effects without the presence of another hormone 3. Antagonism: occurs when a hormone opposes or reverses the effect of another hormone Functions of the Respiratory System: Provide gas exchange between air and circulating blood Moves air in and out of lungs Protects respiratory surfaces from outside environment Produce sound Olfactory sense Alveolar Cells: 1. Type I: simple squamous cells where gas exchange occurs 2. Type II (Septal Cells): free surface has microvilli and secretes alveolar fluid containing surfactant 3. Alveolar Dust Cells: wandering macrophages that removes debris *4 Distinct Processes that must Occur for Respiration: 1. Pulmonary Ventilation: physical movement of air in and out of lungs →inhalation/inspiration and exhalation/expiration 2. External Respiration: gas exchange between the lungs and blood of capillaries 3. Transport of Gases: oxygen and carbon dioxide must travel to tissues cells of the body 4. Internal Respiration: gas exchange from blood of capillaries to and from cells of the body *Gas Laws: 1. Ideal Gas Law: PV=nRT 2. Boyle’s Gas Law: the pressure and volume of a gas have an inverse relationship (when the volume of a gas increases, its pressure decreases, and vice versa) →An expanded volume will lower pressure and allow air to flow into the lungs →P1V1 = P2V2 3. Dalton’s Law: Each gas in a mixture of gasses will exert a pressure independent of other gasses present →Ptotal = P1 + P2 + P3 Group of Neurons in Brainstem that Control Breathing: -Group of neurons is called the Respiratory Center, which is located in the medulla oblongata and the pons. →responsible for generating and regulating the rhythm and depth of breathing. -The respiratory center consists of several interconnected groups of neurons: 1. Medullary Respiratory Centers: →Dorsal Respiratory Group (DRG): Primarily controls inspiration by stimulating the diaphragm and external intercostal muscles. It sets the basic rhythm of breathing and integrates sensory information from chemoreceptors and mechanoreceptors. →Ventral Respiratory Group (VRG): Involved in both inspiration and expiration, especially during forced breathing (e.g., during physical exertion). 2. Pontine Respiratory Centers (in the pons): →Pneumotaxic Center (Pontine Respiratory Group): Modulates the activity of the DRG and VRG, influencing the rate and pattern of breathing. It helps to smooth the transition between inhalation and exhalation, preventing overly prolonged inhalation. →Apneustic Center: Works with the pneumotaxic center to promote deep and sustained breaths, and it provides additional control over the rhythm of breathing. Variables that Provide Information to the Respiratory Center: 1. Central Chemoreceptors →located near ventral surface of the medulla →respond to carbon dioxide changes in cerebrospinal fluid 2. Peripheral Chemoreceptors →extensions of the Peripheral Nervous System (PNS) into blood vessels → respond to changes in oxygen or pH and increase carbon dioxide levels 3. Stretch Receptors →located inside the lungs →terminate inspiration 4. Irritant Receptors →located inside the lungs  →activation causes coughing and sneezing Respiratory Center responds to 3 regulated Variables: Oxygen, Carbon Dioxide, and pH What Influences the Diffusion of Gasses? →Diffusion allows for the exchange of oxygen and carbon dioxide between alveoli and blood Oxygen diffusing from alveoli into blood & Carbon Dioxide from blood into alveoli requires a Concentration Gradient →the Concentration (pressure) of Oxygen in alveoli must be kept at higher level than in blood →the Concentration of Carbon Dioxide in alveoli must be kept at lower level than in blood What is the Function of Carbonic Anhydrase? -Carbonic anhydrase is essential for efficient CO₂ transport, pH regulation, and the maintenance of acid-base balance, making it a key enzyme in respiratory and metabolic processes. What Muscles Control Active Expiration? -Internal Intercostal Muscles and the Abdominal Wall (abdominals) are used for active expiration only What Muscles Control Normal Breathing? Inhalation/Inspiration: 1. Diaphragm - The main muscle of respiration that contracts to increase the thoracic cavity's volume during inhalation. 2. External Intercostal Muscles - These muscles assist by lifting the rib cage, further expanding the chest during inhalation. Exhalation/Expiration: Diaphragm: →During normal (quiet) expiration, the diaphragm relaxes and returns to its dome shape. This decreases the volume of the thoracic cavity, allowing the lungs to recoil, and increases pressure, pushing air out of the lungs. External Intercostal Muscles: →These muscles relax, causing the rib cage to lower and return to its resting position. This further decreases the volume of the thoracic cavity, aiding in the passive process of exhalation. Factor Affecting Dissociation of Oxygen from Hemoglobin: 1. Blood Temperature: increased blood temperature reduces hemoglobin affinity for oxygen 2. Blood pH: lowering blood pH makes blood more acidic which reduces affinity of hemoglobin (Hb) for oxygen 3. Carbon Dioxide Concentration: the higher CO2 concentration in tissue means the less affinity of hemoglobin (Hb) for oxygen * Affinity means the strength of interaction between 2 molecules; how well a molecule can bind to another molecule * Functions of the Circulatory System: Deliver needed materials like oxygen and glucose to cells of the body Remove waste products like carbon dioxide from cells Fight diseases by transporting white blood cells throughout the body What are Intercalated Disks? -specialized structures only found in the heart that connect neighboring cardiomyocytes (cardiac muscle cells) together to form a fusion of cardiac cells. →contain desmosomes that provide strong adhesion between adjacent cardiac muscle cells. Helps withstand the mechanical stress generated during the heart's contractions. →contain gap junctions which allow for direct electrical coupling between adjacent cells. Phases of the Action Potential of Cardiac Muscle Cells (cardiomyocytes): -Depolarization: sodium flows into cardiac muscle cells (sodium influx) →The influx of sodium ions causes the inside of the cell to become more positive, leading to depolarization. -Plateau: caused by calcium (calcium influx) →plateau phase prevents tetanus, ensuring that the heart has enough time to fill with blood before the next contraction occurs. -Repolarization: caused by potassium (potassium efflux) →The efflux of potassium ions decreases the positive charge inside the cell, leading to repolarization and restoring the resting state. Depolarization and Repolarization Phase of the Action Potentials of Pacemaker Cells -Depolarization: 1. Pacemaker cells start from a resting state. When they are stimulated, sodium ions (Na⁺) flow into the cell through special channels called hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. This causes the cell to become more positive (depolarization). 2. As the cell depolarizes, calcium ions (Ca²⁺) also enter the cell (calcium influx), further increasing the positive charge. 3. This phase generates an action potential, leading to heart contraction. -Repolarization: 1. After reaching the peak of depolarization, the voltage-gated calcium channels begin to close. 2. Voltage-gated potassium (K⁺) channels open, allowing potassium ions to flow out of the cell (Potassium efflux) Cardiac Muscle Cell Action Potential Cascade (order of events) 1. Resting State: →The cardiac muscle cell starts at a resting state, around -90 mV. It's more negative inside compared to outside because potassium (K⁺) ions are mostly inside the cell.  2. Depolarization: →When the cell gets a signal (like from pacemaker cells), sodium (Na⁺) channels open. Sodium rushes into the cell, making it more positive (depolarization). 3. Plateau: →After depolarization, calcium (Ca²⁺) channels open, allowing calcium to enter the cell. The influx of calcium balances the potassium leaving the cell, creating a plateau. This prevents the heart from contracting too much (tetanus) and gives it time to refill with blood. 4. Repolarization: →After the plateau, the calcium channels close. More potassium channels open, letting potassium flow out of the cell. The loss of positive charge from potassium makes the inside of the cell more negative again (this is called repolarization). 5. After repolarization, the cell returns to its resting state of about -90 mV, ready to receive another signal. The Cardiac Cycle: 1. Atriole Systole Begins: Atrial Contraction forces blood into ventricles 2. Ventricular Systole (1st Phase): Ventricular contraction pushes AV valves closed 3. Ventricular Systole (2nd Phase): Semilunar valves open and blood is ejected 4. Ventricular Diastole (early): semilunar valves close and blood flows to atria 5. Ventricular Diastole: Chambers relax and blood fills ventricles passively Summary: 1. Atrial Systole: Atria contract and push blood into the ventricles. 2. Ventricular Systole: Ventricles contract, pushing blood into the lungs and body. 3. Ventricular Diastole: The heart relaxes, refilling with blood for the next beat. Fast and Slow Responses to Blood Flow Configuration: -when blood volume increases, it leads to increased blood pressure and triggers either fast or slow responses. 1. Baroreceptor is the Fast Response →Baroreceptors can detect changes in blood pressure within seconds. When blood pressure rises, they quickly send signals to the brain to initiate responses like vasodilation (widening of blood vessels) and decreased heart rate to lower blood pressure. 2. Kidneys and Other Hormonal Systems are Slow Response →Ex) When blood volume is low, the kidneys will retain more water and sodium, which gradually increases blood volume over time. This process can take hours to days to fully adjust. Mechanism for Smooth Muscle Contraction: 1. A signal (such as a nerve impulse or a hormone) triggers the smooth muscle cell to begin contraction. 2. Calcium ions (Ca²⁺) enter the smooth muscle cell from outside the cell or are released from internal stores (like the sarcoplasmic reticulum). 3. The calcium ions bind to a protein inside the cell called calmodulin, forming a calcium-calmodulin complex.  4. This calcium-calmodulin complex activates an enzyme called myosin light chain kinase (MLCK). 5. MLCK adds a phosphate group (phosphorylation) to myosin light chains, which are part of the myosin heads. 6. Phosphorylated myosin heads bind to actin filaments, forming cross-bridges. 7. Myosin heads use energy from ATP to pull the actin filaments, causing the smooth muscle to contract. 8. The muscle remains contracted as long as calcium is present and the myosin heads stay phosphorylated. 9. When calcium levels decrease, the enzyme myosin light chain phosphatase (MLCP) removes the phosphate group from myosin, stopping the contraction. 10. The smooth muscle relaxes as myosin heads detach from actin, and the actin filaments return to their original position. Major Pumps of the Circulatory System: The Heart: 1. Right Atrium: →Receives deoxygenated blood from the body via the superior and inferior vena cava. →Pumps blood into the right ventricle. 2. Right Ventricle: →Pumps deoxygenated blood to the lungs via the pulmonary arteries for oxygenation (pulmonary circulation). 3. Left Atrium: →Receives oxygenated blood from the lungs via the pulmonary veins. →Pumps blood into the left ventricle. 4. Left Ventricle: →Pumps oxygenated blood into the aorta, which then distributes it to the rest of the body (systemic circulation). Skeletal Muscle Pump (moving your muscles): -helps squeeze veins and push blood up toward your heart, especially from your legs, with valves making sure the blood doesn’t flow backward. Respiratory Pump (Breathing): -helps move blood from your lower body to your heart by changing the pressure in your chest and abdomen as you breathe in and out. What Does Angiotensin Do to Blood Vessels? -It is a hormone that helps regulate your blood pressure by constricting blood vessels and triggering water and salt (sodium) intake. Factors that Influence Mean Arterial Pressure: -MAP is the average pressure in a person’s arteries during one cardiac cycle * Normal MAP is 70-100 mmHg* 1. Blood Volume 2. Effectiveness of the heart as a pump 3. Resistance of the system to blood flow  4. Relative distribution of blood between arterial and venous blood vessels What is the Control Center For Blood Pressure? -The Medulla Oblongata →located in the brainstem → integrates signals from baroreceptors and coordinates responses through the autonomic nervous system to maintain blood pressure homeostasis. Relationship Between Blood Flow, Blood Pressure, and Resistance: -Blood flow increases with higher blood pressure and decreases with higher resistance. If blood pressure rises, blood flow will also increase, provided resistance remains constant. Conversely, if resistance increases (like with vasoconstriction), blood flow will decrease even if blood pressure is maintained. What Does Norepinephrine Do to Blood Vessels? -primarily causes vasoconstriction (narrowing) of blood vessels, increasing resistance and elevating blood pressure. It plays a vital role in the body’s acute response to stress, ensuring that blood is redirected to essential organs and tissues during critical situations. Thrombopoiesis (TPO): -Thrombopoiesis = Thromboprotien (TPO) Production -Liver and Kidneys secrete TPO at a constant rate into circulation where it binds to platelets and megakaryocytes →TPO travels to bone marrow and binds to megakaryocytes which stimulates platelet production →TPO bound to platelets is internalized and degraded Erythropoietin (EPO): -Produced when kidneys detect low oxygen levels →Produced by peritubular cells -EPO stimulates production of red blood cells by red bone marrow →as more red blood cells enter blood circulation, O2 levels in blood and tissues increase →When kidneys sens increase of O2, they release EPO which decreases red blood cell production 3 Steps of Hemostasis: -Hemostasis is the process by which the body seals ruptured blood vessels to prevent further blood loss. 1. Vascular Spasm: Blood vessels narrow to reduce bleeding of damaged vessel walls. 2. Platelet Plug Formation: Platelets stick to collagen with the help of von Willebrand factor (VWF) to form a temporary seal. 3. Coagulation: A stable blood clot forms to stop the bleeding. What is Found in Plasma? 1. 90% water 2. Ions 3. Organic Molecules  →amino acids, proteins, glucose, lipids, and nitrogenous waste 4. Trace Elements & Vitamins 5. Gasses →Oxygen and Carbon Dioxide Parts of Innate Barrier Defense: -Body’s 1st line of defense -2 possible barrier defenses 1. Physical: Skin: The outer layer of skin acts as a protective barrier that prevents the entry of pathogens. Mucous Membranes: These line body cavities that are open to the outside (e.g., respiratory, digestive, and urogenital tracts) and trap pathogens in sticky mucus. Cilia: Tiny hair-like structures, especially in the respiratory tract, that sweep away trapped pathogens in mucus. 2. Chemical: Skin Acidity: The slightly acidic pH of the skin (due to sweat) inhibits bacterial growth. Sebum: An oily secretion from sebaceous glands that creates a protective film on the skin and has antimicrobial properties. Lysozyme: An enzyme found in tears, saliva, and mucus that breaks down bacterial cell walls. Gastric Juice: The highly acidic environment in the stomach (due to hydrochloric acid) that kills many ingested pathogens. Characteristics of Lymph: Lymph is a clear, watery fluid circulating through the lymphatic system. It helps maintain fluid balance, supports immune functions, and absorbs dietary fats. Formed from excess interstitial fluid surrounding cells in tissues. Similar to blood plasma but contains fewer proteins, and includes water, electrolytes, white blood cells (especially lymphocytes), and waste products. Lymph flows in one direction, toward the heart, through lymphatic vessels. Passes through lymph nodes, where it is filtered to trap pathogens and debris. Movement relies on skeletal muscle contractions, breathing, and smooth muscle contractions, since there is no central pump like the heart. Plays a role in transporting fats and fat-soluble vitamins from the digestive system into the bloodstream via specialized vessels called lacteals. Characteristics of Phagocytes: -Phagocytosis is the process by which certain immune cells engulf and digest harmful particles, bacteria, or dead cells to protect the body from infection. -Ingest foreign particles and cellular debris 1. Macrophages: consume many cells 2. Neutrophils: die upon consumption  3. Dendritic cells: stimulate adaptive immunity 4. Eosinophils: helpful against parasites; destructive enzymes Characteristics of Interferons: -naturally occurring proteins and glycoproteins that non-specifically defend against viral infections 1. Signal to neighboring cells to destroy RNA and reduce protein synthesis 2. Signal neighboring cells to undergo apoptosis 3. Activate immune cells Characteristics of Complement Proteins: -System of inactive proteins produced by liver -activated in response to pathogens →destroy foreign substance by lysis of pathogens Plasma Cells: -specialized B cells that produce and secrete large quantities of antibodies (immunoglobulins) in response to an antigen. These antibodies bind to pathogens, marking them for destruction and neutralizing their harmful effects. Cytotoxic T Cells: -directly attack and destroy infected or cancerous cells by recognizing specific antigens presented on the surface of these cells. They release perforin and granzymes, which induce apoptosis (programmed cell death) in the target cells. T Helper Cells: -coordinate the immune response by releasing cytokines that stimulate other immune cells, including B cells and cytotoxic T cells. They play a crucial role in enhancing antibody production and facilitating the activation of the entire immune system. Memory Cells: -long-lived cells that remain in the body after an infection has been cleared. They "remember" previous encounters with specific pathogens, allowing for a faster and more robust immune response upon re-exposure to the same antigen, which is essential for long-term immunity. Cytokines: -cell signaling molecules that aid in cell to cell communication. They play essential roles in both defending against infections and in the development of various diseases when their levels are imbalanced. Antibodies: -specialized proteins produced by plasma cells in response to foreign substances (antigens) like bacteria, viruses, and toxins. Methods of Disease Transmission: 1. Direct: the disease is passed directly from one infected person to another person →person-to-person: touches or exchanges bodily fluids with another person ex) kissing →Droplet: spread by coughing or sneezing which causes droplets containing infectious agent 2. Indirect: the disease is passed from person to person even though they have not had direct contact →Fecal-Oral: microscopic amounts of feces are spread between people by mouth. Can happen after not washing hands → Airborne: infectious agent enters air when an infected person coughs, sneezes, or just breathes. 3. Vector: requires another organism to transmit a disease from person to person →Fomites: any surface or object that can carry germs, such as bacteria or viruses, and can spread infections Ex) door knobs or water fountains →Insect Bite: most common form of vector-borne diseases commonly spread through insect bites. Ex) mosquito bites can cause malaria which humans can spread among each other