my q's - physiology of heart

Question 1

systems involved

Answer 1

SNS - sympathetic nervous system
- increases pulse conduction and contraction

PSN - parasympathetic nervous system
- can decrease cardiac output through decreasing contractility

Question 2

preload

Answer 2

• the pressure exerted on a heart ventricle is determined by:
  a) venous blood pressure
  b) the rate of venous return
• vasoconstriction also impacts preload and blood volume (higher blood volume the more preload)

Question 3

cardiac output

Answer 3

• reduced CO results in vasoconstriction and increases blood volume

Question 4

afterload

Answer 4

• the pressure the heart produces to open the valve and eject blood into the artery
• increase of blood pressure = increased afterload
• hypertension = increased afterload

Question 5

heart failure

Answer 5

• often means there’s excessive sympathetic activity and reduced baroreceptor activity (parasympathetic signals)