anatomy and physiology mcqs

Question #306

Aldosterone



Aldosterone is a mineralocorticoid hormone secreted by the zona glomerulosa of the adrenal cortex. Angiotensin-II is the main secretagogue. As a steroid hormone, aldosterone crosses the cell membrane to act on intracellular receptors. In the collecting ducts it causes the loss of K+ and retention of Na+.

Excess, as in Conn’s syndrome, is associated with hypernatraemia, hypervolaemia and hypertension, as well as hypokalaemia and alkalosis.

Deficiency, as in Addison’s disease, is associated with circulatory collapse, as well as hyperkalaemia and alkalosis.

See A Thinking Approach to Physiology, pages 172 - 174.

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