An individual is diagnosed with a condition that prevents the secretion of antidiuretic hormone (ADH) from the pituitary gland. This condition results in the excretion of large volumes of dilute urine and a decrease in the water potential of the blood plasma.
Which of the following explains these physiological effects?
Active transport of sodium ions out of the ascending limb of the loop of Henle is inhibited.
Fewer water channel proteins (aquaporins) are inserted into the cell surface membranes of the collecting duct.
Glomerular filtration rate increases rapidly to compensate for the lack of hormone.
The permeability of the proximal convoluted tubule to water is significantly reduced.
17 exam-style questions on OCR A A Level Biology Excretion as an example of homeostatic control. Each one has a worked solution and a mark scheme showing where the marks go.