Cardiac Muscle Flashcards
0
Q
Contraction and relaxation coordinated by AP generated by?
A
SA (Sinu-Atrial) Node
1
Q
What kind of control for cardiac muscle?
A
Involuntary
2
Q
Conducting system process?
A
AP from SA node
- move through internodal pathways & atria to
- atrioventricular (AV) node then
- through bundle of His to
- L & R bundles to
- purkinje fibers &
- through ventricles
3
Q
What allows AP to move rapidly through cardiac myofibers?
A
Connexin proteins of Gap junctions.
4
Q
Resting membrane potential of cardiac myofibers?
A
-90mV
5
Q
Cardiac muscles prefer glucose or fatty acid for ATP generation?
A
Fatty acids. Produces more ATP than glucose.
6
Q
What causes rapid oxygen transport?
A
Myoglobin.
7
Q
Temporary store for energy to delay ATP depletion?
A
Creatine Phosphate (CrP)
8
Q
Ion causing depolarization?
A
Na+
9
Q
Excitation-contraction coupling process of cardiomyocytes?
A
- AP enters from adjacent cell
- Voltage gated Ca2+ channels open and Ca2+ enter cell
- Ca2+ induces Ca2+ release from RyR
- Ca2+ bind to troponin & move tropomyosin
- MBS exposed and contraction occurs
- Relaxation occurs as Ca2+ unbinds from troponin
- Ca2+ pumped back into SERCA
- Ca2+ moved out of cell as Na+ moves in by Na+/Ca2+ exchanger
- Na+ gradient maintained by Na+/K+ ATPase pump
10
Q
Contraction in which manner?
A
Graded manner
11
Q
What causes increase force of tension?
A
Increase sarcomere length.
