参考答案:
Water is reabsorbed by facilitated diffusion.
(Osmotic reabsorption) requires a concentration gradient/hypertonic medulla/high concentration of Na+
ions in the medulla.
Loop of Henle (2 marks max):
Actively pumps Na+
ions into the medulla by active transport from the ascending loop.
Creating a high Na+ concentration in the medulla.
Acts as a counter current multiplier for Na+
ions
ADH (2 marks max):
Released by the pituitary gland when the blood is hypertonic/tonicity of blood above the set point.
Increases the number of aquaporins/changes location of aquaporins.
Increases rate of water reabsorption into the medulla/bloodstream/lowers volume of urine.
Aquaporins (2 marks max):
Aquaporins are membrane channel proteins for water movement.
Aquaporins can increase in number/relocate to membranes.
Aquaporins can control water reabsorption from the collecting tubule.
本题详细解析:
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