Honors Biology Study Guide Chapter 25.4 25.10 Name Osmoregulation and the Excretory System FUNCTIONS OF THE EXCRETORY SYSTEM OSMOREGULATION Freshwater: Marine: Land Animals: Sources of Nitrogenous Wastes? NITROGENOUS WASTES AMMONIA UREA URIC ACID Nephron = Functional Unit HUMAN URINARY SYSTEM A = Bowman s Capsule and Glomerulus B = Proximal convoluted Tubule (PCT) C = Descending limb of Loop of Henle D = Ascending Limb of Loop of Henle E = Distal convoluted Tubule (DCT) F = Collecting Duct
PROCESSING OF URINE THROUGHOUT THE NEPHRON (DESCRIBE EACH PROCESS) FILTRATION What substances will normally pass out of the blood into the Bowman s Capsule of the Nephron? (What is the composition of the filtrate?) REABSORPTION What regions of the Nephron are responsible for Reabsorption of substances from the filtrate (urine) back to the blood? What type of transport process is used for each substance? SECRETION What regions of the Nephron are responsible for secretion of substances from the from the blood into the urine? What type of transport process is used for each substance? EXCRETION Describe the composition of normal urine. EFFECT OF ADH ON BLOOD VOLUME AND BLOOD PRESSURE What endocrine gland releases ADH? What is the stimulus that causes a release of ADH? What is the target of ADH? What is the response or effect of ADH? How might the action of ADH increase blood pressure? WHAT IS THE ROLE OF ALDOSTERONE? (refer back to table in Chap 26)
PROCESSING OF URINE THROUGHOUT THE NEPHRON Label the figure above. Be sure to label all parts of the nephron and describe the function of each part. Indicate which direction various substances will be transported and if transport would involve active or passive transport mechanisms.
TEST YOUR KNOWLEDGE 1. Which of the following is one way that land animals tend to lose water to their environment? (25.4) A. active transport B. transpiration C. evaporation D. osmosis 2. Most of our nitrogen-containing waste products are a result of. (25.5) A. protein metabolism B. the body's attempts to maintain ph homeostasis C. consumption of foods high in nitrates, such as green vegetables D. drug use 3. Uric acid is the nitrogenous waste excreted by birds, insects, and many reptiles. An advantage of excreting uric acid is that it, but a disadvantage is that it. (25.5) A. is not very toxic wastes a lot of water B. saves energy is highly toxic C. is much more soluble in water than other wastes costs energy D. saves water costs energy 4. Which of the following is a function of the human kidney? (25.6) A. processing of blood to form filtrate material, from which metabolic wastes are discarded B. thermoregulation C. excretion of urine D. conversion of ammonia to uric acid 5. Which part of the nephron is most directly involved in the filtration of blood? (25.6) A. the distal tubule B. the loop of Henle C. Bowman's capsule D. the proximal tubule 6. The fluid that enters the nephrons is called the filtrate. Where does the filtrate come from? (25.6) A. urine B. blood capillaries C. the loop of Henle D. cells of the kidney 7. What is the correct sequence of filtrate processing in the nephron? (25.7) A. secretion, reabsorption, filtration, excretion B. filtration, reabsorption, secretion, excretion C. filtration, reabsorption, secretion D. excretion, secretion, reabsorption, and filtration 8. What is the main function of the distal tubule? (25.8) A. reabsorption B. active transport of amino acids and glucose C. secretion of H+ and reabsorption of HCO3- D. excretion
9. Which of the following substances is generally too large to be filtered from the bloodstream by the kidneys? (25.8) A. glucose B. plasma protein C. water D. urea 10. Which of the following correctly pairs the filtrate component with the appropriate process and location in the kidney? (25.8) A. NaCl secreted in the loop of Henle B. K+ secreted in the distal tubule of the renal cortex C. nutrients reabsorbed in Bowman's capsule D. H2O secreted in the loop of Henle 11. What happens to glucose in the filtrate as it passes through the proximal tubule? (25.8) A. It is filtered. B. It is secreted. C. It is reabsorbed. D. Nothing happens to it in the proximal tubule; it passes into the loop of Henle. 12. What is the main function of the loop of Henle? (25.8) A. active transport of amino acids and glucose B. excretion C. secretion of H+ and reabsorption of HCO3- D. reabsorption 13. The effect of ADH is to. (25.9) A. increase water reabsorption B. increase solute reabsorption C. decrease solute reabsorption D. decrease water reabsorption