Question

Given below is a simplified diagram of the human kidney cut open longitudinally. Answer the questions that follow.

1. Define excretion.
2. Why does the cortex of the kidney show a dotted appearance?
3. Why does the medulla of the kidney show a striped appearance?
4. Write two differences in the composition of the blood flowing through the blood vessels 'A' and 'B'.

Answer 1

1. The process of removal of chemical wastes (mainly nitrogenous wastes) from the body is known as 'excretion'.
2. Due to both Bowman's capsule and the proximal convoluted part lying in it.
3. Henle's loops and collecting ducts in the medulla of the kidneys create a striped or striated look.
4.   
   1. Renal Artery: The blood vessel 'B', i.e., the renal artery, contains dirty blood.
      Renal Vein: The blood vessel 'A', i.e., the renal vein, contains cleaned blood.
   2. Renal Artery: It pours the blood into the glomerulus and Bowman's capsule.
      Renal Vein: It pours blood into the postvena cava. Blood arteries A and B open into the medulla, not the pelvis or ureter.