Regulation of Extracellular Sodium & Water Flashcards
A decrease in MAP activates ______.
the renin/angiotensin axis
______ ==> shift of ECF water into cells ==> decreased ECF volume ==> decreased MAP ==> increased baroreceptor reflexes (arterial and intrarenal) ==> increased renin ==> increased AgII ==> increased aldosterone ==> increased Na reabsorption in distal tubule and collecting duct ==> addition of ingested Na to ECF
Loss of ECF Na
In a function apart from its vasoconstrictive role, _____ acts on cells of the adrenal cortex and causes them to increase aldosterone synthesis.
AgII
_____ is a peptide hormone that is synthesized in neurons located in the hypothalamus of the brain.
ADH
Increased ECF osmolarity causes activation of?
hypothalamic osmoreceptors
The normal Na+ concentration in the ECF is considered to be in the range of _______.
135-145mM
ADH is a peptide hormone that is synthesized in the _______.
hypothalamus of the brain
Losses or gains in ECF sodium cause greater changes in _____ than they do in _____.
ECF volume>Na concentration
The sensors of sodium regulation monitor changes to ______.
ECF volume (not Na concentration!)
ADH release from the post pituitary causes?
increased water reabsorption in the distal t. and collecting duct
How does severe sweating change the osmolarity of the ECF?
it becomes hypertonic
Loss of ECF Na ==> _______ ==> decreased ECF volume ==> decreased MAP ==> increased baroreceptor reflexes (arterial and intrarenal) ==> increased renin ==> increased AgII ==> increased aldosterone ==> increased Na reabsorption in distal tubule and collecting duct ==> addition of ingested Na to ECF
shift of ECF water into cells
Diarrhea represents an ______ loss of ECF via pathological secretion into the gut.
isotonic
Changes in ECF volume have little effect on _____ levels, except when ECF volume falls severely.
ADH
What is ANP?
a potent diuretic peptide that also increases sodium excretion
Due to the two-fold greater volume of the cellular over the ECF compartment, gains (or losses) of sodium from the ECF result in _____-fold greater changes in ECF volume than they do in ECF sodium concentration.
two
Where are the baroreceptors in the heart located?
in the auricle (a.k.a. “left atrial appendage”)
What hormone dilates both the afferent and efferent arteriole?
ANP
Where is ADH stored and released from?
the posterior pituitary
Loss of ECF Na ==> shift of ECF water into cells ==> decreased ECF volume ==> decreased MAP ==> increased baroreceptor reflexes (arterial and intrarenal) ==> increased renin ==> increased AgII ==> increased aldosterone ==> _______ ==> addition of ingested Na to ECF
increased Na reabsorption in distal tubule and collecting duct
This is a potent diuretic peptide that also increases sodium excretion.
ANP
ANP acts to increase filtration by selectively dilating?
both the afferent and efferent arteriole
The reduction in ECF volume in severe sweating is monitored by changes in blood pressure, which to a lesser extent is done by the ______.
arterial high pressure baroreceptors
A decrease in ______ activates the renin/angiotensin axis.
MAP
In a function apart from its vasoconstrictive role, AgII acts on cells of the adrenal cortex and causes them to increase ______ synthesis.
aldosterone
Decreased ICF volume causes decreased LA pressure, which activates a baroreceptor reflex to the _____.
hypothalamus
