Question

Select the INCORRECT statement.

• A. Efferent arteriole has wider lumen than that of afferent arteriole.
• B. Efferent arteriole arises from the glomerulus.
• C. Efferent arteriole divides to form peritubular capillary network around PCT and DCT.
• D. Renal artery enters the kidney and divides into afferent arterioles.

Answer 1

Answer: (C)

Nephrons are structural and functional units of kidney. These consists of Malphigian corpuscle and renal tubule. Malpighian body consists of Bowman's capsule and tuft of capillaries i.e. glomerulus. These capillaries are unique as these are between two arterioles and not between an arteriole and a venule. Afferent arteriole which forms from renal artery enters the capsule and forms the glomerulus which further forms efferent arteriole and leaves the capsule. These then divide to form peritubular capillaries around the renal tubules. Ultrafiltration which is the first step in urine formation takes place because of the difference in diameters of afferent and efferent arteriole to establish the pressure needed for filtration. Afferent has wider lumen as compared to efferent.