Cardiovascular Homeostasis

Question 1

CO venous return curve - 5 main points of this

What happens when you exercise, have haemorrhage, heart failure

Answer 1

• CO = venous return = right atrial pressure
• Increase mRAP = increase CO
• Increase mRAP = decrease venous return
• mRAP = 0, no increase in venous return (venous return must have greater pressure than mRAP to get increase return)
• mean systemic pressure = where venous return = 0
• max venous return = 8l

Question 2

Extrinsic vs intrinsic mechanisms of cardiac homeostasis

Answer 2

extrinsic - autonomic nervous system, endocrine system
Intrinsic -chemoreceptors, osmoreceptors, stretch receptors (monitor distention of heart and arteries and also airways and lungs)

Question 3

ENdocrine system regulation of heart

Answer 3

• adrenaline and noradrenaline - released in response to sympathetic stimulation
• REnin-angiotensin system
• NAP

Question 4

Renin - 3 reasons it is stimualted

Answer 4

JGA - sense low NACL, low blood flow, or b1 receptors are activated

Question 5

Angiotensin 2 effects (5 things)

Answer 5

• increase sympathetic acitvity
• increase na, cl- absorpiton and k secretion to retain more water
• stimulates aldosterone (which increases process above)
• ADH secretion (more water absorption)
• Arteriol vasoconstriction

Question 6

ANP

Answer 6

• made by heart, brain
• released by heart in stimuli to atrial and ventricular distention, in response to heart failure
• cardiac distension, sympathetic stimulation, angiotensin 2 stimualtion, enothelin
• get decrease in GFR to decrease renin release (decrease angiotensin 2)
• also vasodilates vessles
• overall decrease BP and BV to get diuresis

Question 7

sympathetic and parasympathetic supply to heart

Answer 7

• Parasympathetic to heart = from vagus

- Sympathetic - from sympathetic chain (top 3 ganglia