Quiz Questions

Quiz 1. Renal clearance is defined as the quantity of substance removed from the plasma in one minute 4. Glomerular filtration rate (g.f.r) is defined as the volume of plasma filtered by the glomeruli per minute 7. Inulin clearance is used as a measure of g.f.r because inulin a. is not freely filtered b. is not reabsorbed c. is not toxic d. can be readily measured e. metabolised by the cells 14. PAH clearance is used to estimate renal blood flow because PAH is a. rapidly secreted b. freely filtered c. freely reabsorbed d. is metabolised by the renal cells 20. Free water clearance may be defined as the amount of distilled water that must be subtracted from the urine in order to render urine iso-osmotic with plasma. 23. Short-looped nephrons lack the thin ascending limb 25. Generally, there are more long-looped nephrons than short-looped nephrons

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stions

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rest about 20% of cardiac output perfuses the kidneys bout 120 mls of fluid is filtered into the glomeruli per minute ydrostatic pressure remains constant throughout the omerular capillary omerular capillaries are more permeable to proteins than stemic capillaries omerular capillary hydrostatic pressure is greater than owman capsular hydrostatic pressure. odocytes account for about 50% of the barrier to filtration he capillary endothelium accounts for the main filtration arrier in the glomerulus. ncrease in transcapillary hydrostatic pressure increases omerular filtration. More than 50% of the filtered albumin is excreted in the urine. ubuloglomerular feedback autoregulates glomerular filtration

Quiz 3. 4. 5. • • • • • • • • •

T/F About 60% of the filtered glucose is normally reabsorbed in the proximal tubule. The proximal tubule is the main site of reabsorption of filtered amino acids. Reabsorption of water and sodium in the early proximal tubule is ten time greater than in the straight proximal tubule. Reabsorption of chloride is greater in the early proximal tubule than the late proximal tubule. Glucose is selectively reabsorbed by SGLT-1 in the early proximal tubule. Renal threshold of glucose is 375 mg/min. Proximal tubule reabsorbs more than 80% of filtered phosphate. More than 60% of magnesium is reabsorbed in the proximal tubule. Nearly 2/3rd of the filtered potassium is reabsorbed in the proximal tubule. Water is reabsorbed through aquaporins. SGLT-2 has a higher affinity for glucose the SGLT-1 SGLT-2 binds to 2 sodium ions

Quiz 3.

The thick ascending limb of the loop of Henle (TALH) is permeable to water.

6.

TALH absorbs about 30% of the filtered NaCl.

8.

15% of the filtered load of calcium is reabsorbed in the TALH.

10. TALH is a major site for magnesium reabsorption. 12. There is net potassium reabsorption in the TALH. 14. ADH stimulates NaCl reabsorption in the TALH. 16. Potassium is secreted in the DCT. 18. Increased intraluminal sodium concentration increases potassium secretion in the distal convoluted tubule (DCT). 21. Aldosterone increases potassium secretion in the DCT. 10. Reabsorption of NaCl in the TALH is mediated by furosemide sensitive Na+-K+-2Cl co-transport mechanism.

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Quiz 3. The kidney filters about 180L of fluid per day 2. More than 99% of filtered sodium is reabsorbed by the kidneys. 3. Tubular fluid in the proximal tubule is iso-osmotic to plasma 4. Tubular fluid in the distal convoluted tubule is hypotonic to plasma 5. The interstitial osmotic gradient increases from the cortex to medulla 6. The TALH actively transports NaCl into the interstitium 7. ADH decreases the permeability of medullary collecting duct to urea. 8. ADH increases the rate of K+ secretion in the CCT. 9. Urea recycling in the kidney increases during antidiuresis 22. The conc of osmoprotective osmolytes increases from the cortex to the medulla

Quiz 3. 4. 5. 6. 8. 9. 10. 11. 13. 14. 16. 17. 18. 19. 20.

Total body water in an adult is about 25L Infants have relatively more body water than adults Adipose tissue has the highest water content In healthy adults, the osmotic threshold for AVP secretion ranges from 280-285 mOsm/kg H2O ADH release is increased in hypovolaemia ADH release is increased in nausea Angiotensin II stimulates ADH release Ingestion of isotonic saline increases the extracellular fluid volume Atrial natriuretic peptide inhibits tubular sodium reabsorption In nephrogenic diabetes insipidus there is a defect within the V2 receptors in the kidney Aldosterone inhibits the actions of ANF An increase in ECFV increases GFR Interstitial fluid osmolality is greater than that of plasma AVP/ADH is synthesised in the hypothalamus Nicotine stimulates ADH release

Quiz The HCO3-/H2CO3 is the major intracellular buffering system. Normal serum bicarbonate concentration is about 24 mmol/L. Titratable acid is the amount of filtered H+ that is buffered by filtered weak acids. 5. Urine pH cannot be lowered much below 4.4 6. Carbonic anhydrase is present in the brush border membrane of the proximal tubule. • HCO3- formed in the proximal tubule is returned to the systemic circulation via the basolateral Cl-/HCO3- exchanger, AE1. 7. Haemoglobin buffers H+ ions. • Proximal tubular cells produce ammonia from glutamine • Metabolic acidosis leads to alveolar hypoventilation • In metabolic acidosis PaCO2 is increased. • α intercalated cells in the collecting tubule secrete H+. • Proximal tubular ammonia secretion results in the addition of bicarbonate to the blood. • In a given day more H+ bind to HPO42- to form titratable acid than those binding to NH3. 14.The largest fraction of net H+ secretion in the tubule is by NHE3. 15. β intercalated cells secrete HCO3• • •

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Quiz 1. Micturition is aided by the contraction of the detrusor muscles. 2. The internal urethral sphincter is under involuntary control. 3. The pelvic parasympathetic provides the major excitatory input to the urinary bladder. 5. Sympathetic stimulation aids the storage function of the bladder. 6. The pudendal nerve innervates the external urethral sphincter 7. The first urge to micturate is felt when the bladder volume is about 120 – 150 mls. 9. Sensory or afferent signals from the urinary bladder are conducted to the sacral segments of the cord through the pelvic nerve. 8. The efferent signals are sent to the bladder through the pelvic nerve. • Voluntary micturition does not involve the micturition reflex. • The external urethral sphincter consists of striated muscle. • Intravesical pressure increases linearly during bladder filling.

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