Long Term Management of Blood Pressure Flashcards
What is probably not the main gringo in long term control of blood pressure?
The arterial baroreflex
What three hormone systems are involved in long term blood pressure control?
- Renin-angiotensin-aldosterone system
- Antidiuretic factor (ADH, vasopressin)
- Atrial natriuretic peptide
What factor effect long term control of BP?
Blood volume
Where is renin produced?
In the juxtaglomerular (granule cells) of the kidney
What triggers renin production?
- Activation of sympathetic nerves to the juxtaglomerular apparatus
- Decreased distension of afferent arterioles (renal baroreflex)
- Decreased delivery of Na+/Cl- through the tubule.
What are the three triggers of renin production indicative of?
Low MAP
What does renin do?
Converts inactive angiotensinogen to angiotensin I which in turn is converted by angiotensin converting enzyme to angiotensin II
What does angiotensin II do?
- Stimulates release of aldosterone from adrenal cortex (increases Na+ reabsorption and reduces diuresis)
- Increases release of ADh from pituitary (reduces diuresis)
- Vasoconstrictor - increases TPR
What kind of feedback system is the renin-angiotensin-aldosterone system?
Negative feedback
Where is ADH produced?
Synthesised in the hypothalamus and released from the posterior pituitary gland
What triggers ADH release?
- Decrease in blood volume
- Increase in osmolarity of interstitial fluid
- Circulating angiotensin II
What does ADH do?
- Increases permeability of collecting duct
- Causes vasoconstriction (increasing MAP)
Where is ANP produced?
Produced in myocardial cells in the the atria
What stimulates ANP release?
Increased distension of the atrium
What does ANP do?
- Increases excretion of Na+ (natriuresis)
- Inhibits release of renin
- Acts on medullary CV centres to reduce MAP
