Human Physiology Chapters 19-26 Study Guide

Human Physiology Chapter 19: The Kidney Function of the Kidneys – Pages 588 - 589 1. What are the functions of the kidneys? Kidneys maintain normal blood concentrations of ions and water by balancing intake of those substances with their excretions in the urine, obeying the principle of mass balance. 2. Make sure you know what they mean. For example, one of the functions is the regulation of osmolarity. Know what osmolarity means. Kidney function is divided into 6 areas: 1. Regulation of extracellular fluid volume and blood pressure: a. When the ECF volume decreases, blood pressure decreases b. If the ECF volume and blood pressure fall too low, the body cannot maintain adequate blood flow to the brain and other essential organs. 2. Regulation of Osmolarity: a. The body integrates kidney function with behavioral drives such as thirst, to maintain blood osmolarity at a value close to 290 mOsM. What is Osmolarity? 3. Maintenance of ion balance: a. The kidneys keep concentrations of key ions within normal range by balancing dietary intake with urinary loss b. Sodium (Na) is the major ion involved in the regulation of extracellular fluid volume and osmolarity. c. Potassium (K) and calcium (Ca) concentrations are also closely related 4. Homeostatic regulation of pH: a. If extracellular fluid becomes too acidic, the kidneys remove (H) and conserve bicarbonate ions (HCO3-) which act as a buffer. b. When extracellular fluid becomes too alkaline, the kidneys remove (HCO3-) and conserve (H). 5. Excretion of waste: a. The kidneys remove metabolic waste products and xenobiotics, or foreign substances, such as drugs, and environmental toxins. b. Metabolic wastes include creatinine from muscle metabolism and the nitrogenous wastes urea and uric acid. c. A metabolite of hemoglobin called urobilinogen gives urine its characteristic yellow color. 6. Production of hormones a. Synthesis of (erythropoietin) EPO i. EPO regulates red blood cells synthesis b. Release of Renin i. Regulates production of hormones involved in Na+ balance c. Renal enzymes help convert vitamin D into hormones thar regulates Ca2+ balance (activation of vitamin D) Anatomy of the Urinary System – Pages 589 – 592 The urinary system is composed of kidney and accessory structures. The study of kidneys function is called renal physiology, form the Latin word renes, meaning “kidneys”. The Urinary System Consist of Kidneys, Ureters, Bladder, and Urethra Urine production begins when water and solutes move from the plasma into hollow tubules (nephrons) that make up most of the kidneys a. Nephrons modify composition of fluid as it passes through Modified fluid (urine) leaves kidney and passes into hollow tube (ureter) b. There are two ureters, one leading from the kidney to the urinary bladder. Bladder expands and fills with urine until, in a reflex called micturition or urination, the bladder contracts and expels urine through a single tube, the urethra. Women are more prone than men to develop bacterial infections of the bladder and kidneys → Urinary tract infections (UTIs) The Kidneys The kidneys are the site of urine formation. They lie on either side of the spine at the level of the 11th and 12th ribs, just above waist a. Described at being retroperitoneal At any given time, the kidneys receive 20-25% of the cardiac output b. High blood flow is crucial for renal function Renal Arteries: branch off the abdominal aorta, supply blood to the kidneys Renal Veins: Carry blood away from the kidneys to the inferior vena cava The Nephron is the Functional Unit of the Kidney The Kidney’s interior is arranged in two layers the outer cortex and the inner medulla a. The layers are formed by the organized arrangement of microscopic tubules called nephrons 80% of kidneys total nephrons are located in the outer cortex (cortical nephrons) , but the other 20% of nephrons dip into inner medulla (juxtamedullary nephrons) Nephrons is the functional unit of the kidney Overview of Kidney Function – Pages 592 - 594 1. Compare and contrast filtration, reabsorption, secretion, and excretion. a. Refer to figure 19.2, page 593. Look at the direction of the arrows. Three basic processes occur in the nephron: filtration, reabsorption, and secretion Filtration: Movement of fluid from blood into nephron lumen i. Occurs in renal corpuscle Reabsorption: Process of moving substances in the filtrate from lumen of tubule back into blood flowing through peritubular capillaries Secretion: Selectively removing molecules from blood and adding them to filtrate in tubule lumen Vascular Elements of the Kidney: 1. What is the pathway of the flow of blood through the kidney starting with renal artery and ending with renal vein? Blood enters kidney via renal artery then into smaller arteries and then into arterioles in the outer cortex a. At this point, blood vessels form a portal system consisting of two capillary beds in series (one after the other) Blood flow from renal arteries into afferent arteriole then into 1st capillary bed (glomerulus) Blood leaves glomerulus and into efferent arterioles then into 2nd capillary bed (peritubular capillaries) b. In juxtamedullary nephrons, the long peritubular capillaries that dip into inner medulla are call the vasa recta Finally, peritubular capillaries converge to form venules and small veins, sending blood out of kidney via renal vein Function of the renal portal system is to filter fluid out of the blood and into nephron lumen at glomerular capillaries, then reabsorb fluid at peritubular capillaries Tubular Elements of the Kidney The Kidney tubule consists of a single layers of epithelial cells 2. What is the pathway of filtrate from glomerulus to urethral orifice? The nephrons begin with Bowman’s Capsule that surrounds glomerulus a. Combination of Bowmans’s capsule + glomerulus is known as the Renal Corpuscle From the Bowmans capsule, filters fluid flows into Proximal Tubule then into the Loop of Henle b. The Loop of Henle is divided into a descending limb (thin) and ascending limb (thin and thick segments) Fluid then passes into Distal Tubule which drain into a Collect Duct c. Collecting ducts pass from outer cortex through inner medulla and drain into renal pelvis i. Form renal pelvis, the filtered and modified fluid (urine) flows into ureter on way to excretion The nephron twist and folds back on itself so that final part of ascending limb of loop of Henle passes between afferent and efferent arterioles → Juxtaglomerular Apparatus - Proximity of ascending limb and arterioles allows paracrine communication → Key feature of kidney autoregulation Filtration – Pages 594 – 600 The first step in urine formation is the filtration of plasma into kidney tubule Only about 20% of plasma that flows through kidneys filters into the nephrons (Filtration Fraction) a. Remaining 80% of plasma flow into peritubular capillaries Renal Corpuscle contains Filtration Barriers Filtration occurs in the Renal Corpuscle - Substance leaving plasma must pass through 3 filtration barriers before entering tubule lumen Glomerular Capillary endothelium Basal lamina Bowman’s capsule epithelium 1. What 3 pressures effect filtration? (See below.) a. Know the difference between glomerular hydrostatic pressure, glomerular colloid osmotic pressure, and Bowman’s capsule hydrostatic pressure. What drives filtration across walls the walls of the glomerular capillaries? The hydrostatic pressure of blood flowing through glomerular capillaries forces fluid through leaky endothelium a. Favors filtration into Bowman’s capsule → Filtration takes place along nearly the entire length of the glomerular capillaries The colloid osmotic pressure inside glomerular capillaries is higher than that of the fluid in Bowman’s Capsule b. Pressure gradient made by plasma proteins i. Favors fluid movement back into capillaries The fluid pressure opposes fluid movement into the capsule → opposes filtration What is the Glomerular filtration rate (GFR): The volume of fluid that filters into the Bowman’s capsule per unit time 2. How is GFR affected by: a. An increased or decreased glomerular capillary hydrostatic pressure b. An increased or decreased glomerular capillary colloid osmotic pressure c. An increased or decreased Bowman’s capsule hydrostatic pressure d. High or low blood pressure e. Afferent arteriole constriction f. Efferent arteriole constriction 3. What are the parts of the filtration membrane? The book calls them filtration barriers. 4. What is the juxtaglomerular apparatus? a. What is the function of renin? Reabsorption – Pages 600 – 604 1. What is the difference between the active and passive reabsorption of sodium? a. See figure 19.8, page 601 2. Know the mechanism behind the SGLT. a. What happens at the apical surface and which gate? b. What happens at the basal surface and which channels? 3. What is saturation? a. What is transport maximum? Micturition – Pages 612 – 613 1. What is micturition? 2. What is the physiological difference between the internal and external urethral sphincters? Chapter 20: Fluid and Electrolyte Balance Fluid and Electrolyte Balance – Pages 619 - 620 1. Figure 20.1a and b. Know the concepts. a. What is the body’s response to decreased blood pressure/volume? b. What is the body’s response to increased blood pressure/volume? Water Balance – Pages 620 - 629 1. Know the osmolarity of the various sections of the renal tubule compared to the renal tissues that surround them (figure 20.4). Start with the PCT and end with the collecting duct. For example, when does the filtrate become more diluted and when does it become more concentrated? Use terms like isosmotic, hyperosmotic, and hyposmotic. 2. In figure 20.4, what is the osmolarity of the renal medulla? How does it change? How will that affect the renal tubule filtrate? 3. What is vasopressin? a. What is the mechanism of action? b. What is the overall effect? c. See figure 20.5 a, b, and c 4. What is the renal countercurrent multiplier? a. See figure 20.7 c. Sodium Balance & ECF Volume – Pages 629 – 635 1. What is the homeostatic response to an increase in salt ingestion? 2. What is aldosterone? a. What is the mechanism of action? b. How does it affect potassium levels? 3. What are the steps of the RAS? a. What are the effects of angiotensin II? 4. What are the effects of hyperkalemia? 5. What are the effects of hypokalemia? Acid – Base Balance – Pages 641 - 649 1. What is acidosis? What is alkalosis? a. Is the pH high or low? b. How do they affect other organ systems? 2. What is hyperventilation and hypoventilation? a. Is the pH high or low? b. What is the renal compensation for each? c. What is the respiratory compensation for each? 3. What is the renal compensation of alkalosis and acidosis? Chapter 21: The Digestive System Anatomy of the Digestive System – Pages 655 - 659 1. Know where the various valves/sphincters are located, and their functions. a. Include the hepatopancreatic sphincter 2. Know the following short answers: a. What is the shortest section of the small intestine? b. What is the longest section of the small intestine? c. Where does most digestion occur in the GI tract? d. Where does most absorption occur in the GI tract? e. Where does most digestion occur in the stomach? 3. What are the tissues found (most of the time) in each tissue layer of the GI tract? Digestive Functions and Processes – Pages 659 – 663 1. What are the definitions of digestion, absorption, secretion, and motility? 2. What is the difference between tonic and phasic contractions? 3. What are slow-wave potentials? a. What cells are responsible? 4. What are the 3 patterns of contractions? Regulation of GI Function – Pages 665 - 667 1. Know the origin, target, and function of the following hormones: a. Gastrin, CCK, motilin, and secretin (Table 21.1) 2. What is the difference between a short and long digestive reflex? Integrated Function: The Cephalic Phase – Pages 667 – 669 1. In general, what is the cephalic phase? 2. What are the steps of deglutition? (Figure 21.7) Integrated Function: The Gastric Phase – Pages 669 - 673 1. What is the gastric phase? 2. What is the vagal reflex? 3. Know the secretions and their functions from each of the following cells: a. Parietal cells b. Chief cells c. D cells d. G cells e. Neck and surface mucous cells Integrated Function: The Intestinal Phase – Pages 673 - 687 1. What is the intestinal phase? 2. What are some modifications of the small intestine that maximizes the surface area? 3. What is the hepatic portal system? a. What are the parts involved? b. What is the function? 4. Where does __________ digestion begin? a. Carbohydrate b. Protein c. Lipid 5. Know the functions of the intestinal secretions that promote digestion. a. Pancreatic digestive enzymes, enteropeptidase, bile, bicarbonate, mucus, and isotonic NaCl 6. How are monosaccharides absorbed? 7. What is the difference between gastroileal and gastrocolic reflexes? a. What are mass movements? b. What is peristalsis? c. What is the difference between them, and how often do they occur? 8. Know figure 21.15d. What are the vessels of the liver, and what does it carry? a. If it carries blood, know what is in the blood. Chapter 26: Reproduction Sex Determination – Pages 801 - 806 1. What determines the sex of the embryo? a. What are bipotential gonads? b. What is SRY? c. What is TDF? d. AMH? e. DHT? 2. What is the difference between Wolffian and Mullerian ducts? 3. What do each of the embryonic external genitalia develop into for males and females (listed below)? a. Genital tubercle = b. Urethral folds = c. Labioscrotal swellings = Basic Patterns of Reproduction – Pages 806 – 810 1. Know the numbers of chromosomes for: a. Spermatogonia b. Oogonia c. Sperm d. Egg 2. Know the difference between n and 2n. 3. When does the male __________? a. Start producing testosterone b. Start producing sperm c. Stop producing sperm 4. When does the female ________? a. Start producing egg cells b. Stop producing egg cells 5. Know the origin, target, and function (in males and females, if applicable): a. GnRH b. LH c. FSH d. Estrogen e. Testosterone f. Progesterone g. Inhibin Male Reproduction – Pages 810 – 815 1. Where are sperm cells produced (specifically)? 2. Why are the male gonads in the scrotum? 3. What is the difference between spermatogenesis and spermiogenesis? 4. What is the difference between the interstitial cells and the cells of Sertoli? 5. What are the components of semen, and what are their functions? a. Figure 26.7f, page 813 6. What are the male secondary sex characteristics? Female Reproduction – Pages 815 - 823 1. Know the male/female homologous organs. 2. What is the corpus luteum? a. What is the function? b. What happens to it if fertilization occurs? c. What would happen to it if fertilization did not occur? 3. What happens during the follicular phase? a. Pay attention to hormone levels. 4. What days are __________? See figure 26.11 a. The follicular phase b. Ovulation c. Luteal phase d. Menses e. Proliferative phase f. Secretory phase Procreation – Pages 823 - 825 1. Know the phases and what happens during each phase. 2. Know figure 26.13 and what happens during the erection reflex.