Question

Physiology Skeletal Muscle

1.) How does preload in an isolated muscle preparation relate to muscle tone in an intact organism?

Answer 1

Preload is the stress generated within muscle when external force is applied to the relaxed phase of contraction.

In the isolated muscle preparation, preload can be defined as the resting stress which is needed to stretch the muscle to a given starting length.

When there is more calcium then muscle tone will shorten the latency period. Latency period will shorten as the calcium released from the SR will make the myofilament contract and shorten.

The latent period is defined as short delay from time when the action potential reaches the muscle and tension is visualized in muscle. This time needed for calcium to diffuse from SR and bind to troponin. It is the movement of tropomyosin and form cross bridge.