The Human Skeleton and Muscles

The Human Skeleton and Muscles

The human skeleton has three main jobs: support (holding the body up), protection (shielding organs like the brain and heart), and movement (working with muscles).

Muscles and movement

Muscles are attached to bones by tendons. They can only pull, not push, so muscles work in pairs — when one contracts to bend a joint, its partner relaxes, and vice versa to straighten it again.

Protecting vital organs

The skull protects the brain, the ribcage protects the heart and lungs, and the spine protects the spinal cord.

Practice

Name one bone that protects an organ, and which organ it protects.