Long Term Control of Blood Pressure Flashcards
Long term control of blood pressure is probably not mediated by
the arterial baroreflex
Long term control of blood pressure revolves around the control of
plasma volume by the kidney
Long term control involves what three distinct hormone systems?
- Renin-angiotensin-aldosterone system
- Antidiuretic factor
- Atrial natriuretic peptide
Give 3 functions of the kidneys
- excretion of waste products
- maintenance of ion balance
- regulation of pH
- regulation of osmolarity
- regulation of plasma volume
What system creates a very high osmolarity outside the collecting duct of the kidney?
Renal counter-current system
What determines how big the osmotic gradient between the outside and inside of the collecting duct is?
Na+ transport
What will determine whether water follows the osmotic gradient between the inside and outside of the collecting duct?
Permeability of the collecting duct to water
Making the collecting duct very permeable to water will result in
- lots of water reabsorption
- little urine
Making the collecting duct very permeable to water will conserve
plasma volume
If the collecting duct is very permeable will it result in a small volume or hypo or hyper-osmotic urine?
Hyper-osmotic
If the collecting duct is very impermeable will it result in a large volume of hypo or hyper-osmotic urine?
Hypo-osmotic
From what part of the kidney is renin produced?
Juxtaglomerular
What 3 things trigger renin production?
- activation of sympathetic nerves to juxtaglomerular apparatus
- decreased distension of afferent arterioles
- decreased delivery of Na+/Cl- through the tubule
Renin production being triggered is a sign of low
mean arterial pressure (MAP)
Renin converts inactive angiotensinogen to
angiotensin I
Angiotensin I is converted by angiotensin converting enzyme to
angiotensin II
Give three functions of angiotensin II
- stimulates release of aldosterone from the adrenal cortex
- increases release of ADH from pituitary
- vasoconstrictor
Give two effects of aldosterone released from the adrenal gland
- increases Na+ reabsorption in the loop of Henle
- reduces diuresis and increases plasma volume
Give two effects of ADH released from the pituitary
- increases water permeability of collecting duct
- reduces diuresis and increases plasma volume
- increases sense of thirst
What kind of system is the renin-angiotensin-aldosterone system?
Negative feedback system
What tends to be increased by the renin-angiotensin-aldosterone system?
Mean arterial pressure
Where is ADH synthesised?
Hypothalamus
Where is ADH released from?
Posterior pituitary
Give 3 sings of low MAP that trigger ADH release
- decrease in blood volume
- increase in osmolarity of interstitial fluid
- circulating angiotensin II
