The Muscular System

Human Biology & Health Chapter 2.3Pages 50-54

Try This:

• Sit perfectly still!• That means move as little as possible• Try not to move a muscle for a full 60 seconds

Now relax!• What did you notice about this exercise?

Muscle-bound

• There are roughly 600 muscles in your body

• Used in every action you take– Chewing, breathing,

blinking, smiling, etc.

Muscle Action

• Classified according to control

• Voluntary: muscles you consciously control

• Involuntary: muscles you do NOT consciously control– Heart beating, digestion

Types of Muscles3 Types

1. Skeletal2. Smooth3. Cardiac

• Skeletal muscle is connected to your bones• The muscle is connected to bone by

Tendons• React quickly but also tire quickly.

Types of Muscles

• Involuntary muscles• Not banded like Skeletal muscles.• React more slowly and therefore tire slowly.

3 Types1. Skeletal2. Smooth3. Cardiac

Types of Muscles

• Similar to both Skeletal & Smooth muscles• Involuntary and untiring like smooth• Responds quickly and rapidly.

3 Types1. Skeletal2. Smooth3. Cardiac

Muscles at Work

• Put your pen at the far edge of your table

• Place your hands on your lap

• Slowly reach out and pick up your pen

• How do you think your muscles ‘moved’ just now?

Muscles at Work

• Make a “muscle”• How are your muscles

moving now?• What is the lump being

made by this motion?

Working in Tandom

• Muscles can only contract

• They work in pairs: one muscle contracts, the other relaxesBiceps contract when you flex

Triceps contract when you extend your arm.

Exercise and Stretching• Exercising your

muscles makes them stronger

• Stretching (after a brief warm-up) helps prepare muscles for activity

• Increases range of motion and flexibility

Muscle Injuries

• Strain injuries occur when a muscle or Tendon tears– “Pulled” muscles

1. Avoid activity that causes pain in ‘pulled’ area

2. Ice it (no longer than 15 minutes at a time)

3. Elevate it to heart level.

Muscle Injuries

• Sprain injuries occur when a joint is over-stretched or torn

• Ligaments are tissue that connect bones

1. Ankle sprain2. ACL / MCL knee sprains

(Anterior / Medial cruciate ligament)

Exit Pass• What are the 3 kinds of muscle?• What is the only way muscles

can move?

•Star Systems & Galaxies (Ch3.4, p117-120)•Star Systems & Galaxies (Ch3.4, p117-120)

What to Work On• In your notebook, outline

Section 2.4, The Skin• Answer the Review questions

for both Section 2.3 (page 54, #s 1-4) and Section 2.4 (page 62, #s 1-3)

•Star Systems & Galaxies (Ch3.4, p117-120)•Star Systems & Galaxies (Ch3.4, p117-120)