long term control of BP Flashcards
generally how is BP controlled in the long term
control of plasma volume by the kidney
which 3 hormone systems are involved
renin angiotensin aldosterone system atrial natriuretic peptide and brain natriuretic peptide antidiuretic hormon (vasopressin)
name 5 functions of the kidneys
excretion of waste maintenance of ion balance regulation of plasma volume pH regulation osmolarity regulation
what happens when the CD is very permeable to water
lots of water reabsorption
little urine
conserve plasma vol
what happens when the CD is very impermeable to water
little water reabsorption
lots of urine (diuresis)
reduce plasma vol
where is renin produced
juxtaglomerular of the kidney
what triggers renin production
activation of symp nerves to juxtaglomerular apparatus
reduced distension of afferent arterioles
reduced delivery of Na/Cl through tubule
all signal low MAP
what is the function of renin
converts angiotension –> angiotensin I
angiotensin converting enzyme converts angiotensin I —> angiotensin II
what is the function of angiotensin II
stimulates release of aldosterone from adrenal cortex
increased release of ADH from pituitary
vasoconstriction therefore reduced TPR
all increase MAP
what is the function of aldosterone
increased Na reabsorption from LOH
reduced diuresis
increased plasma vol
what is the function of ADH
increased water permeability of CD
reduced diuresis
increased plasma vol
vasoconstriction –> reduced TPR
increased sense of thirst
where is ADH synthesised
hypothalamus
released from posterior pituitary
what triggers the release of ADH
reduced blood vol (cardiopulmonary baroreceptors –> medullary CV centres)
increased osmolarity of ISF (osmoreceptors in hypothalamus)
circulating angiotensin II (triggered by RAAS)
where is atrial natriuretic peptide produced
produced and released from myocardial cells in atria
what triggers the release of ANP
increased distension of atrium (sign of increased MAP)
