Chapter 18/19 (Pt. 6) Flashcards
how does aldosterone increase Na+ reabsorption? (2)
- increase number of Na+ ATPases on distal tubule and collecting duct basolateral membrane, to bring in Na+ from lumen and send out K+
- opens more Na+ in and K+ out channels on apical membranes, ions flow according to conc. gradient
how does atrial natriuretic peptide decrease Na+ reabsorption?
increase BP = heart pumps harder = heart stretches = ANP secreted by atria = ANP blocks synthesis of Na/K ATPases and leak channels = reduces Na+ reabsorption by distal nephron tubules
what is ANP?
atrial natriuretic peptide
what triggers the release of atrial natriuretic peptide?
stretch of cardiac muscle, including within the atria.
ANP inhibits the release of three things. what are they?
aldosterone, renin, and ADH
how do ADH levels regulate water reabsorption?
dehydrated = fluid volume drops = ADH released = ADH binds to kidney, adenylate cyclase –> cAMP -> PKA -> release vesicles with aquaporins on apical side of principle cells to reabsorb water
how are baroreceptors used to monitor blood pressure and control ADH secretion?
if fluid volume drops, pressure drops
what do baroreceptors detect?
pressure
what do osmoreceptors detect?
solute concentration
how do osmoreceptors monitor blood pressure and control ADH secretion?
as fluid volume drop, solute concentration increases
name four important things in controlling the synthesis and secretion of aldosterone?
- angiotensin I
- angiotensin II
- renin
- concentration of plasma Na+
what is micturition reflex?
controls urine release
how is urine retention/release controlled by the detrusor muscle, internal urethral sphincter, and external urethral sphincter?
what are the three structures responsible for controlling urine retention/release?
detrusor muscle
internal urethral sphincter
external urethral sphincter
how is urine retention/release controlled by the detrusor muscle?
relaxes to allow for bladder expansion
bladder fills
stretch receptor activated, AP sent to brain stem
how is urine retention/release controlled by the internal urethral sphincter?
micturition reflex tells IUS to open
contraction of IUS means relaxation of EUS
how is urine retention/release controlled by the external urethral sphincter?
contraction of IUS means relaxation of EUS
EUS is skeletal muscle, meaning voluntary control
what are the two aspects of the micturition reflex?
- brain tells internal urethral sphincter to open
- brain tells detrusor muscle to close
