MCQ Cardiology Answer 21

The correct Answer is B


Hormonal regulation of blood pressure

Renin-Angiotensin system

• Reduced blood volume or renal blood flow
• Kidneys secrete renin
  Leads to production of angiotensin II
  Causes vasoconstriction (increases BP)
  Stimulates secretion of aldosterone by adrenal cortex which increases sodium and water retention by kidney (increases blood volume)
• Epinephrine and norepinephrine
  Sympathetic stimulation of adrenal medulla by CV centre increases secretion of these hormones
  Increase HR and contractility
  Promote vasoconstriction (except in cardiac and skeletal muscle)
• Antidiuretic hormone
  Released by posterior pituitary gland in response to dehydration and/or reduced blood volume
  Promotes vasoconstriction
  Promotes water retention by kidneys
• Atrial Natriuretic Peptide
  Released by cells of right atrium in response to increased venous return
  Lowers BP by promoting vasodilatation and renal excretion of sodium and water

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