The following diagram represents a mammalian kidney tubule (nephron) and its blood supply.

Parts indicated by the guidelines 1 to 8 are as follows:

1. Afferent arteriole from renal artery;

2. Efferent arteriole

3. Bowman's capsule,

4. Glomerulus;

5. Proximal convoluted tubule with blood capillaries;

6. Distal convoluted tubule with blood capillaries;

7. Collecting tubule;

8. U-shaped loop of Henle.

Study the diagram and answer the questions that follow:

(a) Where does ultrafiltration take place?

(b) Which structure contains the lowest concentration of urea?

(c) Which structure contains the highest concentration of urea?

(d) Which structure (normally) contains the lowest concentration of glucose?

(e) Where is most water reabsorbed?

Look at the figure given below. It is a section of a human kidney as seen from the front.

(a) Is it the left kidney or the right one? Give reason in support of your answer.

(b) Is it a longitudinal section or a cross-section?

(c) Name the parts numbered 1 – 5.

(d) Which area/part (give its name and the number given on the diagram) contains the following respectively:

(i) Malpighian capsule

(ii) The pyramids

(iii) Freshly collected urine

Given alongside is the figure of certain organs and associated parts in the human body. Study the same and answer the questions that follow:

(a) Name all the organ-systems shown completely or even partially.

(b) Name the parts numbered 1 to 5.

(c) Name the structural and functional unit of the part marked '1'.

(d) Name the two main organic constituents of the fluid that flows down the part labelled '3'.

(e) Name the two major steps involved in the formation of the fluid that passes down the part labeled ‘3’.

Given alongside is a highly simplified (but also somewhat wrong) diagram of the human kidney cut open longitudinally. Answer the questions that follow.

(a) Define excretion.

(b) Name the functional units of the kidneys.

(c) Why does the cortex of the kidney show a dotted appearance?

(d) Mention two functions of the kidney.

(e) Write two differences in the composition of the blood flowing through the blood vessels, 'A' and 'B'.

Study the diagram given alongside and then answer the questions that follow:

(a) Name the region in the kidney where the above structure is present?

(b) Name the parts labelled 1, 2, 3 and 4.

(c) Name, the stages involved in the formation of urine.

(d) What is the technical term given to the process occurring in 2 and 3? Briefly, describe the process.