K.C.S.E Biology Q & A - MODEL 2018PP2QN01
The diagram below illustrates a section of the mammalian kidney.
(a) Name the structures labelled E and F.
(b) Explain the processes that take place in the regions labelled G and H.
F — Interlobular artery/branch of renal artery;
(b) Region G
At the (glomerulus), the afferent arteriole which brings blood to the glomerulus is wider than the efferent arteriole; this creates high pressure; leading to ultrafiltration; At the proximal convoluted tubule /distal convoluted tubule, substances required by the body/amino acid substances required by the body (amino acids/glucose/vitamins! some water; are selectively re-absorbed (into the blood stream); hence selective reabsorption;
At the descending arm of/limb of the Loop of Henle, water is selectively reabsorbed; At the ascending arm/limb of the Loop of Henle, sodium ions/salts are actively/selectively reabsorbed; At the collecting duct, water is (selectively) reabsorbed: