BIOL 2160 FINAL EXAM REVIEW

BIOL 2160 FINAL EXAM REVIEW CHAPTER 18-19 THE URINARY SYSTEM 1. What are the main functions of the kidneys? a. Primarily responsible for maintaining stability of ECF volume, electrolyte composition, and osmolarity b. Main route for eliminating potentially toxic metabolic wastes and foreign compounds from the body 2. What are the other functions of the kidneys? a. They maintain water balance in the body b. They maintain proper osmolarity of body fluids, primarily through regulating water balance c. Regulate the quantity and concentration of most ECF ions d. Maintain proper plasma volume e. Help maintain proper acid-base balance in the body f. Excreting (eliminating) the end products (wastes) of bodily metabolism 3. What are the kidneys? a. Pair of bean-shaped organs that lie in the back of the abdominal cavity b. Supplied with a renal artery and renal vein c. The kidneys act on plasma flowing through it to produce urine d. Regulate the composition and volume of almost all body fluids 4. What happens to formed urine after the kidneys? a. It drains into the renal pelvis which is located at the medial inner core of each kidney b. Urine is drained into channels called ureters, and stored temporarily in the bladder before it’s emptied through the urethra to outside the body 5. What is the urinary system? a. Consists of urine forming organs (the kidneys) and structures that carry urine from the kidneys to the outside for elimination from the body (ureters, urinary bladder, urethra) 6. What are the ureters? a. Smooth muscle-walled ducts b. They exit the kidney and carry urine to the urinary bladder 7. What is the urinary bladder? a. Temporarily stores urine b. Hollow, distensible, smooth muscle-walled sac c. Periodically empties to the outside of the body through the urethra 8. What is the urethra? a. Conveys urine to the outside of the body b. It is strait and short in a female c. In males it is much longer and follows a curving course from bladder to the outside i. Dual function of providing route for eliminating urine from bladder and a passageway for semen from reproductive organs 9. What is the nephron? a. Mini kidney b. The functional units of the kidneys that do the work of filtering the blood and forming urine c. Consists of renal corpuscle which filters blood and renal tubule which forms the filtrate into urine 10. What is the tubular component of the nephron? a. Hollow fluid-filled tube formed by a single layer of epithelial cells b. Components i. Bowman’s capsule ii. Proximal tubule iii. Loop of Henle 1. Descending and ascending limb iv. Distal tubule v. Collecting duct or tubule 11. What is the vascular component of the nephron? a. Dominant part is the glomerulus i. Ball of capillaries ii. Water and solutes are filtered through the glomerulus as blood passes through it 12. What are the three processes of the basic renal process? End product? a. Glomerular filtration b. Tubular reabsorption c. Tubular secretion d. Urine is the end product e. 13. What is glomerular filtration? a. The bulk flow of protein free plasma from the glomerular capillaries into Bowman’s capsule b. Fluid filtered from the glomerulus into Bowman’s capsule pass through three layers of the glomerular membrane c. During this step, almost everything that CAN be removed from the blood is removed d. Filtrate which will become urine is formed in this process e. Vascular=blood vessels f. Tubular=filtration g. Blood flows to the glomerulus and water gets filtered out of it among other things h. The filtrate that gets removed gets collected into a chamber called Bowman’s capsule 14. Reabsorption occurs . a. In the blood 15. In order for reabsorption to happen what are the five barriers that need to be crossed? a. 1. The luminal membrane of the tubular cell (the membrane facing the inside of the tubule) b. 2. The cytosol from one side of the tubular cell to the other c. 3. Then the basolateral membrane of the tubular cell to enter the ECF (also interstitial fluid) d. 4. Must diffuse through the ECF e. 5. The capillary wall f. Anything that gets secreted crosses the same barriers but in the opposite direction g. 16. The interior cavity of the tubule, or any hollow structure, is the . a. Lumen 17. The walls of the tubule are made up of . a. Endothelial cells 18. What is the difference between passive and active reabsorption? a. Passive involves moving from high concentration in the tubule to low concentration in the blood b. Active reabsorption happens if any one of the steps in transport requires energy—because without energy it wouldn’t happen c. Reabsorption is the selective transport of molecules from the lumen of the renal tubules to the interstitial fluid outside the tubules 19. Describe sodium reabsorption. a. Primary active transport b. The concentration of sodium needs to be maintained in the blood c. The kidneys and the body use a great deal of energy to absorb sodium d. A sodium potassium ATPase, which requires energy, in the basolateral membrane is essential i. There is always more sodium outside the cell than in e. Sodium starts in the lumen, makes its way into tubular cell, diffuses into the cytoplasm, then comes te pump in the basolateral membrane which requires energy, then it diffuses down its concentration gradient into the capillary f. 20. What are the percentages of sodium absorbed in certain areas? a. 2/3 or 67% of sodium is reabsorbed in the proximal tubule right outside of Bowman’s capsule b. 25% of sodium happens in the ascending limb of the loop of Henle c. 8% happens in the distal and collecting tubules 21. Of the total energy our kidneys use-- % is used to reabsorb sodium a. 80 22. What are reabsorbed by secondary active transport? a. Glucose and amino acids are reabsorbed by sodium-dependent secondary active transport because sodium provides the energy 23. Why does urea get passively reabsorbed? a. At the proximal tubule you have sodium and water and urea, an OH molecule b. As the filtrate flows down the proximal tubule, sodium is transported out, water due to osmotic pressure will move in the same direction of sodium (higher solute concentration) c. Whenever the water leaves, the concentration of urea increases because there is less water now d. Now urea is being passively reabsorbed because you have lost so much water from the filtrate so urea moves down its concentration gradient e. We don’t want urea in the blood, but because we need sodium and water we sort of have to ignore it