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**Filtration Pressure Components** 1. Which of the following best describes glomerular capillary pressure (GCP)? - A\) Pressure of filtrate in the lumen that opposes fluid movement - B\) Blood pressure inside the glomerular capillaries that drives fluid out into Bowman's...

**Filtration Pressure Components** 1. Which of the following best describes glomerular capillary pressure (GCP)? - A\) Pressure of filtrate in the lumen that opposes fluid movement - B\) Blood pressure inside the glomerular capillaries that drives fluid out into Bowman's capsule - C\) Osmotic pressure caused by proteins in the blood, drawing fluid back into capillaries - D\) Pressure generated by the movement of ions in the nephron - E\) Pressure in the collecting ducts\ **Answer: B** 2. What effect does capsule hydrostatic pressure (CHP) have on glomerular filtration? - A\) Increases filtration rate by pushing fluid into Bowman's capsule - B\) Opposes glomerular capillary pressure by resisting fluid movement into Bowman's capsule - C\) Promotes reabsorption of ions in the proximal tubule - D\) Has no effect on glomerular filtration - E\) Increases blood pressure\ **Answer: B** 3. Blood colloid osmotic pressure (BCOP) opposes filtration by: - A\) Creating a pressure gradient to push fluid into Bowman's capsule - B\) Drawing water back into the capillaries due to plasma proteins - C\) Forcing blood cells into the filtrate - D\) Increasing the GFR directly - E\) Lowering blood pH\ **Answer: B** 4. Given GCP = 50 mm Hg, CHP = 10 mm Hg, and BCOP = 30 mm Hg, what is the filtration pressure? - A\) 0 mm Hg - B\) 10 mm Hg - C\) 20 mm Hg - D\) 30 mm Hg - E\) 40 mm Hg\ **Answer: B** **Effects of Efferent Arteriole Constriction and Dilation on Filtration** 5. Constriction of the efferent arteriole would: - A\) Decrease glomerular pressure and filtration rate - B\) Increase glomerular pressure and filtration rate - C\) Reduce blood flow to the glomerulus - D\) Lower blood pressure in the afferent arteriole - E\) Have no effect on filtration\ **Answer: B** 6. How does dilation of the efferent arteriole impact glomerular filtration? - A\) Increases glomerular pressure and filtration rate - B\) Decreases glomerular pressure and filtration rate - C\) Raises blood pressure in the afferent arteriole - D\) Enhances reabsorption in the proximal tubule - E\) Has no impact on filtration\ **Answer: B** **Glomerular Filtration Rate (GFR)** 7. What does glomerular filtration rate (GFR) measure? - A\) The amount of urine produced per day - B\) The rate at which blood is filtered in the kidneys, impacting waste removal and fluid balance - C\) The blood pressure in the glomerular capillaries - D\) The reabsorption rate in the proximal tubule - E\) The concentration of proteins in the blood\ **Answer: B** **Intrinsic Mechanisms (Autoregulation)** 8. Autoregulation of GFR includes which of the following mechanisms? - A\) Tubuloglomerular feedback and sympathetic stimulation - B\) Myogenic mechanism and tubuloglomerular feedback - C\) Hormonal release and renin production - D\) Filtration pressure increase and afferent arteriole dilation - E\) Podocyte contraction and relaxation\ **Answer: B** 9. The myogenic mechanism helps maintain stable GFR by: - A\) Constricting afferent arterioles as blood pressure rises to prevent increased renal blood flow - B\) Dilating afferent arterioles as blood pressure rises to increase renal blood flow - C\) Constricting efferent arterioles in response to low blood pressure - D\) Increasing systemic blood pressure - E\) Releasing ADH in response to high blood pressure\ **Answer: A** 10. Tubuloglomerular feedback regulates GFR by: - A\) Constricting the efferent arteriole in response to high blood flow - B\) Sending signals from the macula densa to constrict afferent arterioles when filtrate flow rate is high - C\) Decreasing systemic blood pressure - D\) Increasing the filtration fraction at Bowman's capsule - E\) Secreting renin directly into the blood\ **Answer: B** **Extrinsic Mechanisms (Sympathetic Nervous System and Hormonal Regulation)** 11. During extreme conditions like hemorrhage, sympathetic stimulation affects GFR by: - A\) Constricting small arteries and afferent arterioles, reducing renal blood flow and filtrate formation - B\) Dilating the efferent arteriole to increase blood flow - C\) Increasing renal blood flow and filtrate formation - D\) Enhancing water reabsorption in the loop of Henle - E\) Stimulating the release of aldosterone\ **Answer: A** 12. How does renin contribute to GFR regulation through hormonal control? - A\) It directly lowers blood pressure in the kidneys - B\) It forms angiotensin I, which leads to vasoconstriction and helps maintain GFR - C\) It promotes dilation of the afferent arteriole - D\) It decreases systemic blood pressure - E\) It increases urine output\ **Answer: B** **Cells in the Renal Corpuscle and Juxtaglomerular Apparatus** 13. Podocytes are specialized cells that: - A\) Form the parietal layer of Bowman's capsule - B\) Wrap around glomerular capillaries and form part of the filtration membrane - C\) Line the proximal convoluted tubule to reabsorb glucose - D\) Detect changes in filtrate composition - E\) Regulate renin secretion\ **Answer: B** 14. Where are juxtaglomerular cells located, and what is their function? - A\) In the efferent arteriole; they increase glomerular pressure - B\) In the afferent arteriole; they release renin to regulate blood pressure - C\) In Bowman's capsule; they filter proteins - D\) In the distal convoluted tubule; they reabsorb sodium - E\) In the collecting duct; they adjust urine pH\ **Answer: B** 15. The macula densa cells are located in the: - A\) Proximal convoluted tubule, where they regulate potassium secretion - B\) Afferent arteriole, where they sense blood flow - C\) Distal convoluted tubule, where they detect sodium concentration in the filtrate - D\) Loop of Henle, where they concentrate the filtrate - E\) Collecting duct, where they adjust filtrate pH\ **Answer: C** **Reabsorption and Secretion** 1. What is the primary purpose of reabsorption in the nephron? - A\) To remove essential nutrients and ions from the blood - B\) To add waste products into the bloodstream - C\) To return essential nutrients, water, and ions back into the bloodstream - D\) To lower blood glucose levels - E\) To secrete hormones\ **Answer: C** 2. In the context of kidney function, secretion refers to: - A\) The movement of water back into the bloodstream - B\) Adding waste products and excess ions from the blood into the tubules for excretion - C\) The absorption of glucose from the filtrate - D\) Filtering proteins from the blood - E\) Regulating blood pressure\ **Answer: B** **Proximal Convoluted Tubule (PCT)** 3. What type of cells line the proximal convoluted tubule, facilitating reabsorption? - A\) Simple cuboidal epithelium with microvilli - B\) Stratified squamous epithelium - C\) Simple columnar epithelium without microvilli - D\) Transitional epithelium - E\) Ciliated columnar epithelium\ **Answer: A** 4. The majority of reabsorption in the nephron occurs in the: - A\) Distal convoluted tubule - B\) Loop of Henle - C\) Proximal convoluted tubule - D\) Collecting duct - E\) Renal corpuscle\ **Answer: C** 5. In the PCT, substances pass through the apical membrane, which is located: - A\) On the outer wall of renal tubules - B\) On the inside wall of renal tubules and contains microvilli - C\) Between the capillary walls - D\) Inside the glomerular capsule - E\) In the loop of Henle\ **Answer: B** **Active Transport and Transport Mechanisms** 6. Which transport mechanism in the PCT moves sodium (Na+) out of the nephron cells across the basal membrane? - A\) Passive diffusion - B\) Osmosis - C\) Active transport - D\) Facilitated diffusion - E\) Simple diffusion\ **Answer: C** 7. The concentration of sodium (Na+) is kept low inside nephron cells because: - A\) It is actively pumped out across the basement membrane - B\) It is quickly converted to potassium (K+) - C\) Sodium ions are trapped within the lumen - D\) Sodium is fully reabsorbed in the loop of Henle - E\) It diffuses passively into the blood\ **Answer: A** 8. Through which membrane do glucose, Na+, Cl-, and amino acids primarily enter nephron cells from the filtrate? - A\) Basal membrane - B\) Apical membrane - C\) Lateral surfaces - D\) Bowman's capsule - E\) Renal corpuscle\ **Answer: B** 9. In the PCT, the Na+/Glucose symport mechanism is responsible for: - A\) Moving glucose from the blood into the filtrate - B\) Simultaneously transporting sodium and glucose from the tubule into nephron cells - C\) Excreting sodium and glucose directly into the urine - D\) Exchanging sodium for potassium ions - E\) Passive movement of sodium into cells\ **Answer: B** 10. The Na+/H+ antiport in the PCT assists in: - A\) Excreting glucose from the blood - B\) Regulating pH by exchanging sodium into the cell while moving hydrogen ions out - C\) Reabsorbing chloride ions into the bloodstream - D\) Maintaining high glucose levels in the blood - E\) Regulating blood pressure\ **Answer: B** **Passive Transport, Osmosis, and Facilitated Diffusion** 11. Water reabsorption in the nephron primarily occurs by which process? - A\) Facilitated diffusion - B\) Active transport - C\) Osmosis - D\) Symport transport - E\) Simple diffusion\ **Answer: C** 12. Osmosis in the nephron relies on: - A\) The active pumping of water into the bloodstream - B\) The movement of water following solutes like sodium and chloride that have been reabsorbed - C\) The passive diffusion of ions - D\) The filtration of proteins into the filtrate - E\) The active transport of glucose\ **Answer: B** 13. Facilitated diffusion in the nephron allows which molecules to move efficiently into the bloodstream? - A\) Large proteins - B\) Glucose, amino acids, and ions - C\) Water and lipids - D\) Hormones and small peptides - E\) Potassium and calcium only\ **Answer: B** **Secretion in the Proximal and Distal Convoluted Tubules** 14. In the PCT and DCT, hydrogen ions are secreted primarily to: - A\) Increase glucose reabsorption - B\) Lower blood pressure - C\) Regulate pH in the body - D\) Enhance sodium reabsorption - E\) Control potassium levels\ **Answer: C** 15. Which of the following substances are commonly secreted into the nephron tubule in the PCT and DCT? - A\) Sodium and glucose - B\) Hydrogen ions, potassium ions, and certain drugs - C\) Water and urea - D\) Bicarbonate and glucose - E\) Amino acids and calcium\ **Answer: B** **Secretion of Hydrogen and Potassium** 1. Hydrogen ions (H⁺) are secreted into the filtrate in the proximal tubule by: - A\) Passive diffusion - B\) Symport mechanism - C\) Counter-transport (antiport) - D\) Active transport across the apical membrane - E\) Simple diffusion\ **Answer: C** 2. Hydrogen ions (H⁺) in the proximal tubule can be derived from: - A\) Breakdown of proteins in the filtrate - B\) Carbon dioxide and water reacting in the cells of the tubule - C\) Diffusion from the blood without any cellular reaction - D\) Excreted amino acids - E\) Breakdown of urea\ **Answer: B** 3. In the distal tubule, hydrogen ions (H⁺) and potassium ions (K⁺) are secreted into the filtrate through: - A\) Facilitated diffusion - B\) Counter-transport (antiport) - C\) Simple diffusion - D\) Endocytosis - E\) Osmosis\ **Answer: B** 4. Sodium (Na⁺) and potassium (K⁺) move across the basal membrane by: - A\) Passive diffusion - B\) Active transport - C\) Facilitated diffusion - D\) Secondary active transport - E\) Osmosis\ **Answer: B** **Collecting Duct** 5. Which of the following best describes the role of the collecting duct? - A\) It is part of the nephron responsible for initial filtration. - B\) It plays a role in reabsorbing glucose and amino acids. - C\) It is not part of the nephron but receives filtrate from multiple distal convoluted tubules. - D\) It transports urine directly from the kidneys to the bladder. - E\) It exclusively filters blood cells from the plasma.\ **Answer: C** 6. The main function of the collecting duct is to: - A\) Filter blood - B\) Perform initial reabsorption of nutrients - C\) Finalize the concentration and composition of urine - D\) Secrete large proteins - E\) Maintain glucose levels\ **Answer: C** 7. Which ions are reabsorbed by principal cells in the collecting duct? - A\) Calcium and magnesium - B\) Sodium and water - C\) Potassium and bicarbonate - D\) Chloride and phosphate - E\) Glucose and amino acids\ **Answer: B** 8. Intercalated cells in the collecting duct are primarily involved in: - A\) Regulating glucose levels - B\) Reabsorbing potassium (K⁺) and bicarbonate (HCO₃⁻) and secreting hydrogen ions (H⁺) - C\) Excreting large waste molecules - D\) Absorbing sodium for blood pressure control - E\) Maintaining potassium balance\ **Answer: B** 9. What mechanism in principal cells regulates water movement? - A\) Sodium-glucose cotransporters - B\) Calcium pumps - C\) Aquaporin channels - D\) Antiporters for hydrogen ions - E\) Potassium leak channels\ **Answer: C** **Countercurrent Mechanisms** 10. The countercurrent multiplier, found in the loop of Henle, primarily functions to: - A\) Reabsorb glucose from the filtrate - B\) Concentrate the filtrate by creating an osmotic gradient - C\) Dilute the blood plasma - D\) Filter large proteins from the blood - E\) Excrete sodium into the urine\ **Answer: B** 11. In the descending limb of the loop of Henle, water moves out of the filtrate by: - A\) Active transport - B\) Facilitated diffusion - C\) Osmosis - D\) Passive transport of solutes - E\) Endocytosis\ **Answer: C** 12. In the ascending limb of the loop of Henle, the epithelium is: - A\) Permeable to both water and solutes - B\) Permeable to water only - C\) Impermeable to water but allows solutes to diffuse out - D\) Impermeable to solutes only - E\) Highly permeable to glucose\ **Answer: C** 13. Which structure acts as a countercurrent exchanger to help maintain the medullary concentration gradient? - A\) Distal convoluted tubule - B\) Loop of Henle - C\) Vasa recta - D\) Collecting duct - E\) Proximal convoluted tubule\ **Answer: C** 14. In the vasa recta, as blood flows deeper into the medulla: - A\) Solutes leave the blood and enter the filtrate - B\) Water exits the blood, and solutes enter from the interstitial fluid - C\) The blood becomes more diluted - D\) Water and solutes are both reabsorbed into the blood - E\) Sodium and potassium are actively transported out\ **Answer: B** 15. Near the tip of the renal pyramid, blood flow in the vasa recta: - A\) Reverses direction and moves back toward the cortex - B\) Stops completely - C\) Flows directly into the collecting duct - D\) Moves into the loop of Henle - E\) Filters into the peritubular capillaries\ **Answer: A** 16. The vasa recta\'s role in maintaining a balanced composition while preserving the medullary gradient is achieved by: - A\) Filtering large molecules out of the blood - B\) Absorbing all solutes in the medulla - C\) Removing slightly more water and solutes than it brings in - D\) Excreting excess ions directly into the medullary interstitial fluid - E\) Actively pumping potassium back into the blood\ **Answer: C** **Urea Cycling** 17. Urea cycling contributes to: - A\) Increased blood pH - B\) Maintenance of the osmotic gradient in the medulla - C\) Filtration of glucose into the urine - D\) Formation of bicarbonate ions - E\) Reabsorption of calcium ions\ **Answer: B** 18. In the descending limb of the nephron loop, urea: - A\) Diffuses out of the filtrate into the interstitial fluid - B\) Diffuses from the interstitial fluid into the filtrate - C\) Is actively transported into the collecting duct - D\) Is reabsorbed into the bloodstream - E\) Is converted into amino acids\ **Answer: B** 19. Why does urea remain in the filtrate as it ascends in the nephron loop and distal tubules? - A\) The ascending limb and distal tubules are impermeable to urea - B\) Urea is too large to pass through the membrane - C\) Urea binds to sodium ions and remains in the filtrate - D\) Active transport pumps urea back into the filtrate - E\) Urea is continuously secreted into the filtrate\ **Answer: A** 20. What occurs in the collecting duct in relation to urea? - A\) Urea is reabsorbed into the bloodstream - B\) Urea diffuses into the medullary interstitial fluid - C\) Urea is actively secreted into the filtrate - D\) Urea is converted to ammonia - E\) Urea binds with potassium ions\ **Answer: B** 21. Urea cycling in the kidney involves: - A\) Urea moving between the interstitial fluid and the nephron to maintain a high concentration in the medulla - B\) Constant reabsorption of urea back into the blood - C\) The formation of urea from glucose - D\) The conversion of urea to carbon dioxide in the proximal tubule - E\) Passive diffusion of urea into the renal cortex\ **Answer: A**