Cardiac Muscle

Question 1

Contractile cells of Atria, Ventricle are described as this

Answer 1

Fast

Question 2

Pacemaker cells rising phase is kicked off by of the increased permeability of these ions

Answer 2

Na2+

Question 3

The rising phase of the fast response action potential is the result of a sudden increase in this.

Answer 3

Permeability of Na+

Question 4

Resting phase voltage is largely due to this current.

Answer 4

I - KI - inward rectifier

Question 5

Protein mechanical attachments in desmosomes

Answer 5

adherens

Question 6

These junctions allow electrical current to flow from cell to cell

Answer 6

gap junctions

channnels formed by connexin

Question 7

P wave signifies this

Answer 7

Atrial depolarization

Question 8

QRS complex is site of these things

Answer 8

Ventricular depolarization and masked atrial repolarization

Question 9

Ventricular repolarization on ECG

Answer 9

T wave

Question 10

Total duration of ventricular systole signified by this

Answer 10

QT interval

Question 11

Conduction time through atria and AV node on ECG

Answer 11

PR interval

Question 12

Describe the parasympathetic effects on membrane potential

Answer 12

Release of Ach causes increased permeability of K+, slowed HR, neg. chronotropic effect.

Question 13

What is the approximate length of refractory period for cardiac contractile cells?

Answer 13

250 ms

Question 14

What are the keys of sympathetic control on the heart?

Answer 14

Release of NE increases HR and has a positive chronotropic effect

Question 15

Most Ca2+ stores in the body are found here

Answer 15

Sarcoplasmic reticulum