RAAS Basics Flashcards
what are the body fluid compartments
- ICF
- ECF
- Interstital fluid
- plasma volume
ICF is how many liters and what percent of the body
- 28L
- 67%
interstitial fluid is how many liters and what percent of the body
- 11 L
- 25%
plasma volume is how many liters and what percent of the body
- 3L
- 8%
role of effective arterial blood volume (EABV)
- part of arterial circulation responsible for organ perfusion
what happens if EABV is decreased
- the kidney retains Na and H2O
EABV is sensed by
- afferent receptors
where are these afferent receptors located
- carotid sinus
- aortic arch
- left ventricle
- kidney (JGA)
EABV can be reduced by factors that
- reduce arterial blood volume
- increase vascular capacitance
- reduce cardiac output
factors that reduce arterial blood volume
- hemorrhage
- dehydration
factors that increase vascular capacitance
- cirrhosis
- sepsis
factors that reduce cardiac output
- congestive heart failure
renin is a
- proteolytic enzyme
renin is made by the
- kidney
role of renin
- convert angiotensinogen to angiotensin 1
renin initiates cascade that
- support blood pressure
- defends circulating blood volume
what synthesizes renin
- granular juxtaglomerular cells
what are granular juxtaglomerular cells
- modified smooth muscle cells
where are granular juxtaglomerular cells located
- located in media of the afferent arteriole
stimulation of renin release
- decreased effective circulating volume
- stimulation of baroreceptors/decrease Cl- in tubule at macula densa
- increased sympathetic tone
- renin release into systemic circulation
high pressure baroreceptors
- carotid sinus
- aortic arch
- afferent arteriole
low pressure baroreceptors
- central veins
- atria
angiotensinogen is produced by
- the liver
angiotensin I
- inactive decapeptide
- precursor for angiotensin II
angiotensin II
- octapeptide
- derived from angiotensin I
angiotensin II derived from angiotensin I after
- cleavage of C-terminal peptide by ACE
what is the key active product of RAAS
- angiotensin II
most effects of angiotensin II on the vascular and transport functions are mediated by _____
- AT1 receptors
role of angiotensin II binding to AT1 receptors
- aldosterone release from zone glomerulosa of adrenal gland
physiologic effects of angiotensin II
- arteriolar vasoconstriction
- sodium and water retention
ACE is found on
- endothelial cells
- lungs and kidneys
role of ACE
- catalyzes angiotensin I (inactive) to angiotensin II
- converts bradykinin to inactive metabolites
drugs that block ACE are important in treatment of
- hypertension
- heart failure
ACE inhibitor extracted from
- venom in 1960s
what is the rate limiting step
- JGA secretion of renin
- to convert angiotensinogen to angiotensin I
result of arteriolar constriction
- increase peripheral resistance
- increase systemic arterial pressure
result of increased renal Na+ retention and increased extracellular fluid
- increased cardiac output
negative feedback of increasing systemic arterial pressure
- increase renal perfusion pressure
- decrease baroreceptor sensitivity
- decrease renal sympathetic activity
- decrease secretion of renin
negative feedback of increasing ECF
- increase GFR and decrease proximal resorption of NaCl
- change in NaCl at macula densa
- decrease secretion of renin
most people with primary hypertension have ____
- increased renin levels
low renin hypertension good response to
- diuretics
- calcium channel blockers
renin and aldosterone levels in chronic kidney disease
- increased renin
- increased aldosterone
renin and aldosterone levels in renal artery stenosis
- increased renin
- increased aldosterone
renin and aldosterone levels in primary aldosteronism
- decreased renin
- increased aldosterone
RAAS in congestive heart failure
- decreased CO and PVR
- decreased EABV ->activation of RAAS
- increased renal sodium retention
- increased venous pressure
- edema builds up in peripheries and lungs
