The Muscular System

1. The Muscular System Chapter 14 Section 3

2. Types of Muscle • Involuntary muscles: muscle that are not under conscious control • Breathing and digesting food • Voluntary muscles: muscle that are under your conscious control • Smiling, turning a page in a book

3. Types of Muscle • Three types of muscle tissue • Skeletal muscle • Smooth muscle • Cardiac muscle • Some of these muscle tissues are involuntary, and some are voluntary

4. Skeletal Muscle • Location: attached to the bones of your skeleton • Provides the force that moves your bones • Can react quickly and tire easily • At each end of a skeletal muscle is a tendon • Tendon • Strong connective tissue that attaches muscle to bone • Striated Muscle • Cells appear banded • Voluntary or Involuntary? VOLUNTARY

5. Smooth Muscle • Location: inside of many internal organs, stomach and blood vessels • Voluntary or Involuntary? INVOLUNTARY • Work automatically to control certain movements • Example: digestion • Not striated • React more slowly and tire more slowly

6. Cardiac Muscle • Location: only in heart • Voluntary or Involuntary? INVOLUNTARY • Muscle cells are striated • Cardiac muscle does not tire • Repeated contractions, heartbeats

7. Muscles at Work • Muscles contract when they receive messages from the nervous system • Can only contract, not extend– they must work in pairs • One muscle contracts, the other muscle relaxes to original length • Muscle action involved in bending the arm at the elbow • The biceps muscle must contract and the triceps muscle returns to its original length