BIO 235 Assignment 3 Question and Answers | 100% Guaranteed Success

BIO 235 Assignment 3 Question and Answers | 100% Guaranteed Success Some patients who suffer from hypertension (high blood pressure) are prescribed medications that are in the category of angiotensin-converting enzyme (ACE) inhibitors. Explain why these drugs are used to combat hypertension. - answer-a. Angiotensinconverting enzyme (ACE) inhibitors are commonly used to treat hypertension, or high blood pressure. These drugs work by blocking the activity of an enzyme called angiotensinconverting enzyme, which is involved in the regulation of blood pressure. Angiotensinconverting enzyme is responsible for converting angiotensin I, a hormone produced in the blood, into angiotensin II. Angiotensin II is a potent vasoconstrictor, meaning it narrows the blood vessels, increasing the resistance to blood flow and elevating blood pressure. When ACE inhibitors are given, they block the activity of angiotensin-converting enzyme, reducing the production of angiotensin II and decreasing the resistance to blood flow. This leads to a decrease in blood pressure and improved blood flow Describe the fate of an RBC traveling from the heart to the left elbow and back to the heart. - answer-a. From the heart, the RBC will enter the ascending aorta and then the aortic arch. The RBC will exit the aorta through the left subclavian artery, continue on that route through the axillary artery and into the brachial artery. At the elbow, the blood cell will exit into one of the small distributing arteries, move into a capillary bed, and then into venules in the elbow region. The RBC will then probably enter the median cubital vein and move into either the basilic or the cephalic vein. The basilic vein drains into the brachial vein, which drains into the axillary vein. Explain the steps that result in antibody production and describe the process that results in an activated B-cell. - answer-a. The specialized WBC (white blood cell), often called B lymphocytes (the B cells) help in the production of antibodies. Some of the steps involved in the production of antibodies are mentioned below: i. Entering of antigen-bearing agents (pathogen) into the tissue ii. Encountering of antigens by B cells iii. B cell gets activated by antigen with the help of costimulatory signals provided by T cells iv. The B-cell then proliferates and gets differentiated into an antibody effector cellv. These B cells synthesize bulk quantities of soluble antibodies and have the same unique antigen-binding site, similar to that of cell surface antibodies. vi. The secretion of antibodies initially begins by the effector B cell, while they are still small lymphocytes. vii. The B cells can further get differentiated to form the plasma cells, which can secrete and synthesize antibodies. b. The activation of B cell is carried by the binding of BCR (B cell receptor) to the antigen which causes the cell to differentiate and proliferate. This binding initiates some events such as altered gene expression, antigen internalization, and re-organization of the B cell cytoskeleton. c. The MHC (major histocompatibility complex) is recently produced in endosomes that are targeted by the B cell receptor for further internalization. As a result, the process can be presented to CD4+ cells, thereby recruiting the support cells to facilitate maximum B cell activation. These B cells differentiate into plasma cells which secrete antibodies. State Boyle's Law and explain how it relates to the process of pulmonary ventilation. - answer-a. Boyles law states that the pressure of gas is inversely proportional to the volume of the gas. As the size (volume) of the thoracic cavity increases, the pressure within the thoracic cavity decreases from 760-758mmHg. Describe the Bohr Effect. Explain how PO2 in the lungs and tissue cells determines whether oxygen binding or dissociation occurs with hemoglobin. - answer-a. The Bohr Effect refers to the observation that the affinity of hemoglobin for oxygen decreases as the concentration of carbon dioxide (CO2) and hydrogen ions (H+) in the blood increases. Hemoglobin, a protein in red blood cells, binds to oxygen in the lungs where the oxygen partial pressure (PO2) is high and releases oxygen in the tissues where the PO2 is low. The binding and release of oxygen by hemoglobin is influenced by several factors, including the concentration of carbon dioxide and hydrogen ions in the blood. When carbon dioxide (CO2) is produced by the tissues and enters the bloodstream, it combines with water to form carbonic acid (H2CO3). This reaction can lead to an increase in the concentration of hydrogen ions (H+) in the blood, which can alter the pH of the blood. The increase in hydrogen ions (H+) has the effect of decreasing the affinity of hemoglobin for oxygen. As a result, hemoglobin releases more oxygen in the tissues, where the PO2 is low and the concentration of CO2 and hydrogen ions is high, and binds less oxygen in the lungs, where the PO2 is high and the concentration of CO2 and hydrogen ions is low. Define the term percent saturation of hemoglobin and identify the factors that affect the percent saturation of hemoglobin. What is the significance of these factors in the delivery ofoxygen to tissues? - answer-a. This can primarily be explained by an oxygen-hemoglobin dissociation curve that is a relationship between partial pressure of oxygen Vs and amount of oxygen bound to hemoglobin. The curve is a sigmoid shaped curve. Factors affecting this curve are as follows - b. Ph changes i. If the ph decreases that is turns more acidic the curve shifts more to the right that is the affinity of hemoglobin for oxygen decreases as H+ ions bind to hemoglobin. This results in oxygen dissociation. Whereas when ph increases or becomes more alkaline the affinity of hemoglobin increases for oxygen shifting the curve to the left. This is famously known as the Bohr effect. c. Temperature changes i. Increase in temperature or hyperthermia will cause a right shift of the curve that is increased dissociation. This occurs as the cells are working harder in a high temperature and need more oxygen for functioning, whereas hypothermia or decreased temperature shifts the curve towards left. d. Carbon dioxide i. High PCO2 shifts the curve towards right that is more towards dissociation as CO2 increases concentration of H+ ions which then act the same way as discussed in ph and also some of the co2 binds directly with hemoglobin not leaving much space for oxygen. Low PCO2 has the opposite effect shifting the curve towards left. e. 2,3 Bisphosphoglycerate i. This is a naturally occurring molecule produced during glycolysis process. Increase in its concentration shifts teh curve towards the right whereas decrease shifts it towards the left. 2,3 BPG has the capacity to bind to the hemoglobin molecule and changing its conformation and shifting it to the right in higher concentrations. f. Carbon monoxide i. When carbon monoxide binds to hemoglobin it increases the affinity of the unbound spaces on hemoglobin for oxygen shifting the curve towards left. Thi Describe the structures and functions of the enteric nervous system. - answer-a. the enteric nervous system or intrinsic nervous system is one of the main divisions of the autonomic nervous system and consists of a mesh like system of neurons that governs the function of the gastrointestinal tract. b. Structures- the enteric nervous system is embedded in the lining of the gastrointestinal system, beginning in the oesophagus and extending down to the an*s. The neurons of the enteric nervous system are collected into two types of ganglia. They are myenteric ( auerbach's ) and submucosal ( Meissner's) plexuses. i. Auerbach's plexus1. these are a collection of unmyelinated fibers and postganglionic autonomic cell bodies that lie between the circular and longitudinal layers of the muscularis externa. ii. Meissner's plexus 1. these are present in the submucosal layer of the gastrointestinal tract. c. Functions of enteric nervous system are : i. peristalsis 1. peristalsis is a series of radially symmetrical contractions and relaxations of muscles which propogate down the muscular tube. ii. segmentation 1. segmentation contractions are the contractions in the intestine unlike peristalsis, they involve the contraction and relaxation of muscles in one direction. Segmentation occurs simultaneously in both directions as the circular muscles alternatively contract. This allows for thorough mixing of intestinal contents, known as chyme, to allow greater absorption. iii. secretion 1. the secretion of gastrointestinal hormones is also a function of enteric nervous system. It regulates the secretion of gastrin and secretin. Briefly describe production and effects of secretin. - answer-a. Secretin is synthesized and secreted by S cells in the small intestine(Doudenum), and neurons in the brain. Secretin release is mainly stimulated by gastric acid delivered into the duodenal lumen. In addition, secretin is released by digested products of fat and protein. b. When HCl passes from the stomach into the duodenum, secretin is released into the bloodstream and stimulates the acinar cells of the pancreas to secrete water and bicarbonate into the pancreatic ducts that drain into the duodenum. How does the hypothalamus regulate food intake? - answer-a. Hunger signals: The hypothalamus receives signals from various parts of the body that indicate hunger, such as the presence of low glucose levels in the blood or empty stomach. These signals stimulate neurons in the hypothalamus to produce hunger-stimulating hormones, such as neuropeptide Y and agouti-related protein. b. Release of hunger hormones: The hunger-stimulating hormones produced by the hypothalamus are then released into the bloodstream, which travels to the pituitary gland, stimulating the release of more hormones that stimulate hunger, such as growth hormonereleasing hormone (GHRH) and corticotropin-releasing hormone (CRH). c. Stimulation of hunger center: These hunger hormones then travel to the hypothalamus, where they stimulate the hunger center, causing feelings of hunger and the desire to eat.d. Signals of fullness: The hypothalamus also receives signals from the body indicating fullness, such as high glucose levels in the blood, stretch receptors in the stomach, and hormones such as cholecystokinin, insulin, and leptin. These signals inhibit the hunger center, decreasing hunger and causing feelings of fullness. e. Regulation of hunger center: The balance between hunger-stimulating and fullness signals in the hypothalamus regulates food intake. If the hunger signals are stronger, the person will feel hungry and want to eat, while if the fullness signals are stronger, the person will feel full and not want to eat. Define the major challenge during the postabsorptive state and describe the postabsorptive state effects of epinephrine, norepinephrine, glucagon, and cortisol. - answer-a. The major challenge during the postabsorptive state is to maintain glucose homeostasis, or the balance between glucose utilization and glucose production. In the postabsorptive state, which occurs between meals, the body relies on stored glucose (glycogen) and fat for energy and must regulate glucose production to prevent hypoglycemia (low blood glucose). The postabsorptive state effects of epinephrine, norepinephrine, glucagon, and cortisol are as follows: b. Epinephrine: Epinephrine, also known as adrenaline, is released from the adrenal gland in response to stress or low blood glucose. In the postabsorptive state, epinephrine increases glucose utilization by stimulating glucose release from glycogen in the liver, and by increasing glucose uptake in the muscles. It also increases glucose production by stimulating gluconeogenesis, the process by which glucose is produced from noncarbohydrate sources such as amino acids. c. Norepinephrine: Norepinephrine is also released from the adrenal gland in response to stress or low blood glucose. In the postabsorptive state, norepinephrine acts similarly to epinephrine, increasing glucose utilization and production to maintain glucose homeostasis. d. Glucagon: Glucagon is a hormone produced by the pancreas that stimulates glucose release from glycogen in the liver. In the postabsorptive state, glucagon acts to increase glucose production and maintain glucose homeostasis by stimulating gluconeogenesis and glucose release from glycogen. e. Cortisol: Cortisol is a hormone produced by the adrenal gland in response to stress. In the postabsorptive state, cortisol acts to increase glucose utilization and production by stimulating glucose release from glycogen in the liver, increasing glucose uptake in the muscles, and stimulating gluconeogenesis. Cortisol also has the effect of in Describe the flow of blood through the kidneys. - answer-a. Arterial blood enters the kidneys through the renal arteries and branches into smaller arterioles. à The arterioles then divide into a network of capillaries, called the glomerulus, which is surrounded by Bowman's capsule. à Blood is filtered through the capillaries and Bowman's capsule, and the filtrate flows into the renal tubules, where various waste products and excess fluids are removed. à The renal tubules then reabsorb necessary substances, such as glucose,electrolytes, and water, back into the bloodstream. à The now-modified filtrate, now called urine, flows into the renal pelvis and is transported to the bladder via the ureters for elimination from the body. à The blood, now depleted of waste products and excess fluids, flows back into the renal veins and returns to the heart through the inferior vena cava.