Nephron Structure and Function

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What is the approximate number of nephrons in each human kidney?

2 million

5 million

500,000

1 million (correct)

What is the main function of the glomerulus?

To store urine

To filter waste and excess substances from the blood (correct)

To produce hormones that regulate kidney function

To regulate blood pressure

What is the diameter of the pores in the fenestrated endothelium of the glomerular capillaries?

50 to 60 nanometers

100 to 120 nanometers

70 to 90 nanometers (correct)

150 to 180 nanometers

What is the structure that forms the dilated, blind end of the nephron?

Bowman's capsule Signup and view all the answers

What is the function of the afferent arteriole?

To supply the glomerulus with blood Signup and view all the answers

What is the significance of the difference in diameter between the afferent and efferent arterioles?

It increases the rate of filtration Signup and view all the answers

What is the function of the specialized epithelium of Bowman's capsule?

To separate the blood from the glomerular filtrate Signup and view all the answers

What is the size of the glomerulus in diameter?

200 um Signup and view all the answers

What is the function of the efferent arteriole?

To drain the glomerulus Signup and view all the answers

What is the relationship between the number of nephrons and the size of the kidneys between species?

The number of nephrons varies independently of the size of the kidneys Signup and view all the answers

What opposes the capillary hydrostatic pressure in the glomerular capillaries?

Oncotic pressure of the plasma proteins Signup and view all the answers

What is the approximate osmolality at the tips of the papillae?

1,200 mOsm/kg of H2O Signup and view all the answers

What happens to the fluid in the descending limb of the loop of Henle?

It becomes hypertonic Signup and view all the answers

What is the approximate percentage of filtered water that enters the distal tubule?

20% Signup and view all the answers

What is the maximum urine flow that can be produced during a water diuresis?

16 ml/min Signup and view all the answers

What can cause water intoxication?

Drinking large amounts of hypotonic fluid Signup and view all the answers

What is the result of water intoxication?

Swelling of the cells, leading to convulsions and coma Signup and view all the answers

What can lead to water intoxication when not monitored carefully?

Administration of oxytocin after parturition Signup and view all the answers

What is the approximate time it takes for water diuresis to begin after ingesting a water load?

15 minutes Signup and view all the answers

What is the function of podocytes in the glomerular capillaries?

To form filtration slits along the capillary wall with their pseudopodia Signup and view all the answers

What is the result of a decrease in plasma osmolality after water absorption?

Inhibition of vasopressin secretion Signup and view all the answers

What is the effect of norepinephrine on renal vessels?

Constriction of the interlobular arteries and afferent arterioles Signup and view all the answers

What is the effect of prostaglandins on renal blood flow?

Decreased blood flow in the renal medulla and increased blood flow in the renal cortex Signup and view all the answers

What is the effect of a high protein diet on glomerular capillary pressure?

Increased glomerular capillary pressure and increased renal blood flow Signup and view all the answers

What is the purpose of autoregulation of renal blood flow?

To maintain a constant renal blood flow despite changes in arterial pressure Signup and view all the answers

What is the function of Angiotensin 2 in renal autoregulation?

To constrict the efferent arterioles Signup and view all the answers

What is the requirement for a substance to be used to measure GFR?

It must be freely filtered through the glomeruli and neither reabsorbed nor secreted by the tubules Signup and view all the answers

What is the reason for the high pressure in the glomerular capillaries?

The afferent arterioles are short, straight branches of the interlobular arteries Signup and view all the answers

What is the function of inulin in measuring GFR?

To measure glomerular filtration rate Signup and view all the answers

What is the result of inhibiting Angiotensin converting enzyme in patients with poor renal perfusion?

Renal failure Signup and view all the answers