RAAS Flashcards
What is the principal function of the alpha intercalated cells? How does aldosterone help these cells accomplish this? Describe the pumps in these cells including which are powered with ATP and which are not.
1) decrease the acidity of the blood, by removing H+.
2) Aldosterone acts on two important proton pumps that drive H+ out of the cells (and into the filtrate) by kicking them into overdrive.
3) There are three pumps: the first is an ATP driven pump that drives protons into the filtrate, the second is a Na+/H+ anti-porter (no ATP, uses Na+ concentration gradient), and the third is a K+/H+ anti-porter (ATP driven).
What are the four triggers for ADH release in the body?
1) high osmolarity 2) nerve fibers in the superior and inferior vena cava, and the right atrium detecting less stretching of their walls; indicative of low blood volume. 3) nerve fibers in the aortic arch and carotid sinuses detect a decrease in blood pressure. 4) angiotensin II acts on the hypothalamus causing a release of ADH from the posterior pituitary.
How do you determine which membrane of a polarized cell is apical and which is basolateral?
The apical membrane will face inward toward the lumen and the basolateral membrane will face outward toward the intersititium.
In the juxtaglomerular apparatus how do the macula dense cells detect low blood pressure and then act to increase it?
The macula densa cells release prostaglandin to act on sympathetic nerves innervating the smooth muscle of the afferent arteriole and the action of these nerve cells on the juxtaglomerular cells causes them to release renin, thus indirectly increasing bp.
