Know Your Muscles…

The human body has three types of muscle.

• Cardiac muscle
• Smooth muscle
• Skeletal muscle

Cardiac muscle is found in the heart. It is able to beat constantly without getting tired. Smooth muscle is found in hollow organs like the stomach and intestines.

Skeletal muscle attaches to your bones and helps you to move.

Skeletal muscles connect to bones by tendons and enable bones to move at joints. Because they can only contract (pull), muscles act in pairs called antagonistic pairs.

Humans have an endoskeleton – which means that all the bones are on the inside. Insects (and other arthropods) have their structural pieces on the outside called an exoskeleton.

Human bones serve a number of purposes. They protect soft organs; for example the cranium protects the brain and the ribs protect the lungs. Bones allow movement at joints where they are connected by ligaments. Bones also contain marrow which is where red blood cells are produced.

Questions…

1. What kind of muscle is in the biceps?
2. Other than for protection, name one other job performed by your bones.
3. What word describes pairs of muscles which work against one another?
4. Suggest another class of arthropod other than an insect.
5. What is…
   1. a tendon?
   2. a ligament?