cardiovascular control mechanisms Flashcards
renin-angiotensin-aldosterone system (RAAS): recall the organisation and role of the RAAS, and synthesis pathway of angiotensin II
what are juxtaglomerular cells, what do they line and do
specialised smooth muscle cells lining afferent arteiole leading to proximal convoluted tubule that release renin enzymes when blood pressure decreases
what nervous system stimulates renin release
sympathetic
what do macula densa cells line and do
line distal convoluted tubule and sense Na+
what happens in macula densa cells when there is a low blood pressure
sense less Na+ as more reabsorbed (higher water potential in blood), so they release prostaglandins
what do prostaglandins do
stimular juxtaglomerular cells to produce renin
what does renin do
cleaves angiotensinogen produced by liver to angiotensin I
angiotensin I to aldosterone production mechanism
blood enters lungs, allowing ACE to convert it to angiotensin II, which stimulates aldosterone production when it enters zona glomerulosa of adrenal cortex
4 functions of angiotensin II
causes vascular smooth muscle contraction, causes kidney to reabsorb more water (increasing stroke volume), causes PPG to secrete ADH, causes adrenal gland to secrete aldosterone which increases water reabsorption in kidneys
