The Muscular System

Chapter 21-3

Science Words

• Muscle• Voluntary muscle• Involuntary muscle• Skeletal muscle• Tendon• Smooth muscle• Cardiac muscle

Moving the human body

• Muscle-an organ that contracts and gets shorter- this provides the force to move your body parts.

Muscles of thebody

Muscle Control

• Voluntary muscles- muscles that you are able to control

• Examples are leg and arm muscles

• Involuntary Muscles- you can not move them consciously. They just keep working

• Examples- heart

Types of Muscles-skeletal

• Skeletal Muscles-muscles that move bones

• Attached to bones by tendons• Most numerous in the body• Look striped or striated• Voluntary muscles

Types of Muscles-Smooth Muscles

• Smooth muscles- nonstriated• Involuntary• Move the internal organs• Contract and relax slowly• Example- small intestine

Types of Muscles-Cardiac Muscle

• Cardiac muscle-found only in the heart

• Involuntary• Striations• Contracts about 70 times a

minute every day of your life.

Types of Muscles

Types of muscles

How Muscles Work

• Skeletal muscles-when one muscles contracts- another muscle relaxes

• Muscles always pull- never pushes

• Muscles use glucose• Produce thermal energy when

they contract• Muscles that are not exercised

become smaller

How muscles work

Muscles and bones work together

Working together

A review