Biology 9700 · AS & A Level · Homeostasis in mammals

Homeostasis in mammals — practice question

(a)[3]

Fig. 6.1 displays a section of the Bowman’s capsule in a kidney nephron. Name structures A, B and C.

(b)[2]

Fluid is pushed into the Bowman’s capsule by ultrafiltration, producing the glomerular filtrate. Describe the role of structure B in ultrafiltration.

(c)[2]

The chief constituent of the glomerular filtrate formed in the Bowman’s capsule is water. Most of this water is taken back as the filtrate moves along the nephron. • $180\,\text{dm}^3$ of water forms part of the glomerular filtrate each day. • $1.4\,\text{dm}^3$ of water leaves the body in urine each day. Calculate the percentage of water in the glomerular filtrate that is reabsorbed as the glomerular filtrate passes along the nephron. Show your working and give your answer to one decimal place.

(d)[7]

Describe how antidiuretic hormone (ADH) acting on the cells of the collecting duct leads to the reabsorption of water in the glomerular filtrate.

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