CardioVascular Physiology 1

Question 1

Myocardial Cells (Myocytes)

Answer 1

99% of heart cells, force producing straited musce fibres
- contain actin/myosin and xb’s

Question 2

Autorhythmic (pacemaker cells

Answer 2

1% of heart cells which generate spontaneous, rhythemic AP’s that signal myocyte contraction

Question 3

Excitation-Contraction of Cardiac Myocytes

Answer 3

1) AP enters from adjacent cell
2) voltage gated calcium channel opens
3) caclium entry induces calcium release through RyR channels (CICR)
4) local release causes calcium sparks
5) summed sparts generate a calcium signal
6) calcium binds to troponin to initiate contraction

Question 4

Cardiac Myocytes relaxation

Answer 4

1) relaxation occurs when calcium unbinds
2) calcium is pumped back into the SR, or exchanged with sodium by the NCX antiporter

Question 5

Arteries

Answer 5

take blood away from heart

Question 6

Veins

Answer 6

take blood back to the heart

Question 7

Portal Circulation

Answer 7

blood transfer from one capillary bed to another capillary bed

Question 8

Pericardium

Answer 8

fluid filled sac of strong connective tissue that wraps around the heart

Question 9

Cardiac Vs Skeletal Muscle Fibre

Answer 9

Cardiac Muscle Fibers are:
1. smaller with 1-2 nuclei per fibre
2. irregular branching cells connected by intercalated disks
3. larger T-tubules
4. smaller SR
5. mitochondria occupy 1/3 of the volume

Question 10

Desmosomes function

Answer 10

physical coupling allowing force to be transferred

Question 11

Gap junctions Function

Answer 11

electrical coupling

Question 12

Pulmonary Circulation

Answer 12

blood movement between heart and lungs
- right ventricle

Question 13

Systemic Circulation

Answer 13

blood movement between heart and rest of the body
- left ventricle