SS3. Renin

Question 1

Where can the macula densa cells be found?

Answer 1

In the distal convoluted tubule.

Question 2

What type of endothelial cells line the afferent arterioles?

Answer 2

1) Smooth muscle cells
2) Juxtaglomerular cells filled with granules, aka as granular cells.
3) Messenger cells for support/ keeping the whole thing together, aka juxtaglomerular apparatus, goal is to release renin.

Question 3

What are key triggers for the Juxtagranular cells to release renin?

Answer 3

1) Low blood pressure sensed by JG cells in afferent arteriole
2) Sympatic nerve endings attached to JG cells. When they fire, JG cells release renin
3) Macula densa cells in the distal convoluted tubule. Sense low Na, which comes with a lowbp. Sends out prostaglandin, a paracrine hormone, into JG.