L15 - Myocyte Contraction Coupling Pt2 Flashcards
Where is passive tension generated?
At set sarcomere length
What is isometric tension?
The amount of tension generated when a sarcomere is stretched to a certain length.
What proteins are important in generating isovolumetric tension?
Titin and desmin
What is titin?
A protein that links in from the Z-disk into the myosin.
Comes in various lengths.
What does the length of titin determine?
How much passive tension can be generated. Shorter = greater tension.
What is desmin?
The protein that links the sarcomeres together, found at the end of Z disks.
What is the active muslce tension?
How much the tension goes up after an action potential is fired in the muscle.
What does stretching cardiac muscle do?
Inreases tension and activates stretch-activated calcium ion channels, causing more calcium entry from the ECF.
What does Starling’s Law state?
- The strength of contraction depends on the sarcomere length.
- Larger length = greater contraction.
What is velocity of shortening?
The force that must be overcome to eject blood. = afterload
What is the relationship between pre-load and after-load?
- At a given velocity the muscle exerts greater tension if there is a larger pre-load.
- At a given after-load velocity of shortening is greater if there is a greater pre-load.
