Which best describes the top and bottom images of muscle contraction?

a. the top image is more relaxed than the bottom image.
b. the top image has greater actin-myosin interactions than the bottom image.
c. the bottom image is more relaxed than the top image.
d. the bottom image has fewer overlaps than the top image.

The ribht answer is a.

* Muscle contraction results from the coordinated contraction of each of the muscle cells.

There are four phases during the contraction of a "typical" muscle cell:

- the excitation or the stimulation which corresponds to the arrival of the nervous message on the muscular fiber;

- the excitation-contraction coupling which groups together all the processes making it possible to transform the nerve signal received by the cell into an intracellular signal towards the contractile fibers;

- the contraction itself;

- the relaxation which is the return of the muscular cell to the state of physiological rest.

* There are two types of muscle contraction:

isometric contraction when the length of the muscle does not change when contracting (supports a load);

anisometric contraction (or isotonic) when there is a change in the length of the muscle, with a rapprochement of the points of insertion of the muscles it is concentric and eccentric when these move away;