cardiac physiology

Question 1

what is the pressure, wall thickness and lumen size of arteries?

Answer 1

high pressure, thick walls, small lumen

Question 2

what is the pressure, wall thickness and lumen size of veins?

Answer 2

low pressure, thin walls, large lumen

Question 3

what is stroke volume?

Answer 3

the volume of blood pumped by one ventricle

Question 4

what is the equation for cardiac output?

Answer 4

stroke volume x heart rate

Question 5

explain how cardiac muscle contracts?

Answer 5

action potential opens L type voltage gated Ca2+ channels which release Ca2+ and then activate ryanodine receptors to allow the sarcoplasmic reticulum to release Ca2+ which binds to troponin and causes the actin myosin filaments to slide over each other, when muscle relaxes Ca2+ returns to the sarcoplasmic reticulum via the SERCA pump

Question 6

what is the sequence of depolarisation in heart contraction?

Answer 6

SA node, AV node, bundle of HIS, purkyne fibres

Question 7

which nerves and neurotransmitters increase and decrease heart rate?

Answer 7

parasympathetic rereleasing acetylcholine decreases heart rate, sympathetic releasing noradrenaline increases heart rate

Question 8

describe a normal ECG?

Answer 8

hill, dip, peak, dip, hill

Question 9

systole and diastole, which is relaxation and which is contraction?

Answer 9

systole = contraction
diastole = relaxation