L19: Myocardial Contractility Flashcards
1
Q
What enzyme does the myosin contain?
A
ATPase
2
Q
What is the structure of the myosin?
A
Thick thilaments with globular heads
3
Q
What is the structure of actin?
A
Smaller molecule with 2 strands with an alpha helix of myosin woven around it
4
Q
What does tropomyosin do?
A
Prevent contraction in resting state via inhibition of myosin and actin interaction
5
Q
What does troponin T do?
A
Ties the troponin complex to actin and tropomyosin
6
Q
What does troponin I do?
A
Inhibit ATPase activity
7
Q
What does troponin C do?
A
Binds calcium
8
Q
When does CICR happen? In which phase of action potential
A
Phase 2
9
Q
Why does CICR happen?
A
The influx of calcium into myocytes in phase 2 is insufficient to trigger myofibril contraction
