Renin-Angiotensin System Flashcards
What is the rate-limiting step in formation of Angiotensin II?
renin secretion (from JG apparatus)
Juxtaglomerular cells are specialized vascular cells of the JG apparatus located where?
afferent arteriole of kidney
What is the function of JG cells?
synthesis, store, secrete renin into blood
Term for specialized tubular epithelial cells a part of the Juxtaglomerular Apparatus.
macula densa
Function of Macula Densa
act as chemoreceptors to sense NaCl to trigger JG cells to make renin
When the macula densa senses (low/high) NaCl, this stimulates JG cells to produce renin.
low
What receptors are part of the JG apparatus and sense pressure to affect the production of renin?
intrarenal baroreceptors
The juxtaglomerular apparatus is innervated by the (SNS/PSNS) so when there is decreased afferent activity, this causes a(n) (increase/decrease) in renin.
SNS
increase
What two steps of the synthesis of Angiotensin II regulate its circulation?
- secretion of renin
- ACE (angiotensin converting enzyme)
Renin’s role in the synthesis of angiotensin II.
convert angiotensinogen –> angiotensin I (inactive)
Role of ACE in the synthesis of angiotensin II.
convert angiotensin I (inactive) –>
angiotensin II (active)
What are the 3 primary physiological roles of the Renin-Angiotensin system?
- control ECF Na+
- control ECF volume
- control arterial pressure
(T/F) The Renin-Angiotensin system regulates water reabsorption.
False
Match each to whether Angiotensin II will increase or decrease it:
- cardiac contractility
- Sympathetic Nervous System
- ADH
- ACTH secretion
- cardiac hypertrophy
- Norepinephrine
- Sensitivity of arterial baroreflex
- aldosterone
- up
- up
- up
- up
- up
- up
- down
- up
Angiotensin II acts to increase SNS, NE, ADH, thirst, and aldosterone, all which influence increased _________.
Na+ reabsorption
