long term control of blood pressure Flashcards
long term control of blood pressure
controlled by the kidney system
function of the kidneys
Excretion of waste products
Maintenance of ion balance
Regulation of pH
Regulation of osmolarity
Regulation of plasma volume
how does kidney regulate plasma volume
by controlling sodium transport in the body and thus determining how big an osmotic gradient is
transport of sodium ions
active reabsorption of sodium in the loop of Henle which causes an increase in the absorption of water in the collecting duct
permeability of the collecting duct
increased permeability causes and increased absorption of water and vv.
where is renin produced
produced by juxtaglomerular cells of the kidney
what triggers the production of renin
activation of sympathetic nerves
decreased distention of arterioles ( renal baroreflex)
decreased delivery of sodium and chloride through the tubule
what does renin do
converts angiotensinogen to angiotensin 1 which is converted to angiotensin 2 and its effect is vasoconstriction.
what does angiotensin 2 do?
stimulates release of aldosterone
increases the release of ADH from the pituitary
causes vasoconstriction
action of ADH
increases the permeability of water in the collecting duct and reduces diuresis
action of aldosterone hormone
increases the permeability of sodium ions in the loop of Henle
where is ADH produced
synthesised in the hypothalamus
and released from the posterior pituitary
what triggers ADH release ?
decreased blood volume
increased osmolarity in interstitial fluid
circulating angiotensin 2 which is triggered by the renin angiotensin aldosterone system
what does ADH do
Increases the permeability of the collecting duct to H2O, therefore reduces diuresis and increases plasma volume
Causes vasoconstriction (hence its alternative name vasopressin), therefore increasing MAP
where is ANP and BNP produced
produced in the myocardial cells
released from the ventricles
what are the triggers in ANP and BNP release
increased distension of the atria and ventricles
what does ANP and BNP do
Increase excretion of Na+ (natriuresis)
Inhibit the release of renin
Act on medullary CV centres to reduce MAP
