10.3 Regulation Of Contraction

Question 1

Majority thickness of heart wall

Answer 1

Myocardium

Question 2

Lining inside of myocardium/lumen

Answer 2

Endocardium

Question 3

Epicardium aka

Answer 3

Visceral layer of pericardium (outside layer)

Question 4

Endocardium has a layer of

Answer 4

Epithelial tissue. Dense irregular connective tissue

Question 5

Myocardium comprised of

Answer 5

Myocardiocytes

Question 6

Intercalated discs

Answer 6

Bridges between the cells containing gap junctions (where calcium can pass from cell to cell)

Question 7

Sino-Atrial node

Answer 7

Can depolarize spontaneously, sets pace 100-110 bpm (kept slower by parasympathetic signal vagal tone)

Question 8

HR

Answer 8

70-80 beats/min at rest
Systole - contraction
Diastole - expansion

Question 9

Other pacers of heart

Answer 9

AV node and purkinje fibers

Question 10

Dense irregular tissue layer separates the atrium from ventricles preventing conduction

Question 11

Pacemaker cells have what

Answer 11

A particular membrane protein (funny channels, HCN) allowing sodium to leak in constantly

Question 12

Myocardiocytes have

Answer 12

Prolonged AP and contraction from Ca plateau

Question 13

ECG

Answer 13

Measure voltage changes in heart,
- P wave = atrial depolarization
- QRS com = ventricular depolarization
- T wave = ventricular repolarization
- Atrial depolarization hidden in QRS