Question

Which is/are the known function(s) of the sympathetic innervation of the kidneys?

a) Increase glomerular filtration rate
b) Constrict afferent arterioles
c) Increase renin release
d) All of the above

Answer 1

The known functions of sympathetic innervation of the kidneys include increasing glomerular filtration rate, constricting afferent arterioles, and increasing renin release.

Step-by-step explanation:

The sympathetic innervation of the kidneys has multiple known functions, including:

1. Increase glomerular filtration rate: When blood pressure increases, sympathetic stimulation causes vasoconstriction of the afferent arterioles, which reduces the volume of blood flowing through the kidneys. This redirection of blood to other organs decreases the glomerular flow and consequently the filtration rate.
2. Constrict afferent arterioles: The increased sympathetic activity directly causes vasoconstriction of the afferent arterioles, further reducing blood flow through the kidneys.
3. Increase renin release: If blood pressure falls, sympathetic nerves stimulate the release of renin from the liver. Renin increases the production of angiotensin II, which is a powerful vasoconstrictor. Angiotensin II stimulates aldosterone production, leading to the reabsorption of more Na+ and water, thus augmenting blood volume.