2 - Renal BP control Flashcards
What is volume-loading hypertension?
High blood pressure created by increased volume
What is primary aldosteronism?
excess aldosterone caused by a tumor in the adrenal glands that secretes aldosterone
What are two ways the kidney controls BP?
- Directly increasing/decreasing fluid and sodium output/retention
- R-A-A
Where is renin synthesized and stored?
Juxtaglomerular cells
Where are juxtaglomerular cells located?
walls of the afferent arterioles immediately proximal to the glomeruli
Which way do afferent arterioles carry blood in the kidney?
Efferent?
Afferent takes blood TO the glomerulus
Efferent arteriol takes blood AWAY from the glomerulus
Is renin a vasoactive substance?
No. It’s just an enzyme.
When arterial pressure falls, renin release is stimulated three ways:
- Baroreceptors
- decreased sodium in the macula densae
- Increased SNS activity
How long does renin persist in the blood?
30-60 minutes
How long does Angiotensin II directly affect vasoconstriction?
1-2 minutes
rapidly broken down
How long does it take for the R-A-A to be fully active?
About 20 minutes
What are the three roles of Angiotensin II?
- Potent direct vasoconstrictor (brief)
- Constricts efferent arteriole, causing salt and water retention
- Stimulates adrenal glands to release aldosterone
What is the body’s best system for ensuring changes in salt intake do not change arterial pressure?
R-A-A
In a baby with coarctation of the aorta, BP in the upper body will be ______ than BP in the lower body
40-50% Higher
Why do pre-eclamptic women have high blood pressure?
- Substances secreted by the placenta injure epithelial cells and reduce nitric oxide release
- the glomerular membrane of the kidney is thickened (likely autoimmune) and the kidney increases pressure to ensure adequate urine output
