1. Human body. Alvar tedremägi 9kl

2. Why do people have muscles.

3. muscles Muscle cells contain contractile filaments that move past each other and change the size of the cell. Muscles can cause either locomotion of the organism itself or movement of internal organs.

4. Skeletal muscle is anchored by tendons a to bone and is used to effect skeletal movement such as locomotion and in maintaining posture.

5. Smooth muscle is found within the walls of organs and structures such as the esophagus, stomach, intestines, bronchi, uterus, urethra, bladder, blood vessels, and the arrector pili in the skin.

6. Cardiac muscle is also an "involuntary muscle" but is more akin in structure to skeletal muscle, and is found only in the heart.

8. Gross anatomy The gross anatomy of a muscle is the most important indicator of its role in the body. The action a muscle generates is determined by the origin and insertion locations. One particularly important aspect of gross anatomy of muscles is pennation or lack thereof.

9. summary To sum up, people need muscles to live.

10. References. http://en.wikipedia.org/wiki/Muscles