Cardiovascular Physiology

Question 1

Route of depolarization through heart

Answer 1

SA node => internodal pathway and bachmans bundle => AV node => bundle of his => bundle branches => purkinje fibers

Question 2

How does the action potential go through the heart?

Answer 2

through gap junctions

Question 3

Which cells in heart have automaticity

Answer 3

SA node, av node, and purkinje fibers

Question 4

List fastest to slowest speed of mycoardial cells

Answer 4

SA nodes and AV node > atrial pathways, bundles of his, ventgricular muscle > purkinje

Question 5

What is ohm’s law

Answer 5

chang ein voltage (Va-Vb) /Resitance (Rab)

Question 6

What is resting membrane potential

Answer 6

-90 mV

Question 7

Draw action potential for myocardial muscles

Question 8

Draw action potential for pacemaker

Answer 8

Question 9

What are three mechanisms to slow SA firing

Answer 9

1)decrease slope of phase 4 2) increase threshold 3) decrease resting membrane potential

Question 10

What are the four phases of cardiac cycle

Answer 10

Phase 1) AV valves open ventricular filling Phase 2) closing of av valve isovolumenteric contraction 3) phase 3 ejection phase 4) isovolumentric relaxation