1. Is there more than 1 kind of muscle? How are they different from each other?

There are 3 categories of muscle tissue:

1. skeletal muscle:
has striations
is under voluntary control
cells have several nuclei
is usually found attached to bones
is involved in movement of the body, such as in walking

2. cardiac muscle:
has striations
is not under voluntary control (is involuntary)
cells have 1 or 2 nuclei
cells have Y-shaped branching shape
cells are connected at intercalated discs
is found only in the heart

3. smooth muscle
has no striations
is involuntary
cells have only 1 nucleus
is found in hollow organs such as the stomach & in tubes such as blood vessels

2. What is the difference between isotonic muscle contraction and isometric muscle contraction?

In an isometric muscle contraction, the length of the muscle remains the same, but the force being exerted changes.

In an isotonic muscle contraction, the force being exerted remains the same throughout the contraction, but the length of the muscle changes.