30 Questions
What is the approximate number of nephrons in each human kidney?
1 million
What is the main function of the glomerulus?
To filter waste and excess substances from the blood
What is the diameter of the pores in the fenestrated endothelium of the glomerular capillaries?
70 to 90 nanometers
What is the structure that forms the dilated, blind end of the nephron?
Bowman's capsule
What is the function of the afferent arteriole?
To supply the glomerulus with blood
What is the significance of the difference in diameter between the afferent and efferent arterioles?
It increases the rate of filtration
What is the function of the specialized epithelium of Bowman's capsule?
To separate the blood from the glomerular filtrate
What is the size of the glomerulus in diameter?
200 um
What is the function of the efferent arteriole?
To drain the glomerulus
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
What opposes the capillary hydrostatic pressure in the glomerular capillaries?
Oncotic pressure of the plasma proteins
What is the approximate osmolality at the tips of the papillae?
1,200 mOsm/kg of H2O
What happens to the fluid in the descending limb of the loop of Henle?
It becomes hypertonic
What is the approximate percentage of filtered water that enters the distal tubule?
20%
What is the maximum urine flow that can be produced during a water diuresis?
16 ml/min
What can cause water intoxication?
Drinking large amounts of hypotonic fluid
What is the result of water intoxication?
Swelling of the cells, leading to convulsions and coma
What can lead to water intoxication when not monitored carefully?
Administration of oxytocin after parturition
What is the approximate time it takes for water diuresis to begin after ingesting a water load?
15 minutes
What is the function of podocytes in the glomerular capillaries?
To form filtration slits along the capillary wall with their pseudopodia
What is the result of a decrease in plasma osmolality after water absorption?
Inhibition of vasopressin secretion
What is the effect of norepinephrine on renal vessels?
Constriction of the interlobular arteries and afferent arterioles
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
What is the effect of a high protein diet on glomerular capillary pressure?
Increased glomerular capillary pressure and increased renal blood flow
What is the purpose of autoregulation of renal blood flow?
To maintain a constant renal blood flow despite changes in arterial pressure
What is the function of Angiotensin 2 in renal autoregulation?
To constrict the efferent arterioles
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
What is the reason for the high pressure in the glomerular capillaries?
The afferent arterioles are short, straight branches of the interlobular arteries
What is the function of inulin in measuring GFR?
To measure glomerular filtration rate
What is the result of inhibiting Angiotensin converting enzyme in patients with poor renal perfusion?
Renal failure
Learn about the anatomy of the nephron, the functional unit of the kidney, including its structure, size, and components. Understand the role of glomerulus and capillaries in the nephron. Test your knowledge of kidney function and anatomy!
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