THE MUSCULAR SYSTEM

(Section 2)

WARM-UPComplete the BONES QUIZ

BONUS QUESTION! (WORTH ONE POINT)

NAME ONE TYPE OF MOVABLE JOINT

MUSCLES

A MUSCLE IS AN

ORGAN THAT CAN RELAX AND CONTRACT PROVIDES THE FORCE TO MOVE YOUR

BODY PARTSVOLUNTARY MUSCLES: Muscles that you are

able to control INVOLUNTARY MUSCLES: Muscles that you

cannot control

3 TYPES OF MUSCLES 1. SKELETAL MUSCLES

Move bones The most common type of muscle

TENDONS are thick bands of tissue

that attach muscle to bones.

Voluntary muscles

Contract quickly and tire more easily

Look striped, or Striated (STRI ay tud)

2. CARDIAC MUSCLEFound only in the HEARTIs striated, like the

Skeletal Muscles

3. SMOOTH MUSCLES Found in:

Intestines

Bladder

Blood vessels

Other internal organs

Involuntary muscles They work without you thinking about it

Non-striated muscles (not striped) Contract and relax slowly

STRIATED MUSCLE (Skeletal and Cardiac) NON STRIATED MUSCLE (Smooth)

Other key points to know: SKELETAL MUSCLES work together to make you

move When one muscle of a pair CONTRACTS, the

other RELAXES

Muscles always pull Muscles become larger or smaller over time

Depends on whether or not they are used! Used muscles= BIGGER

Unused muscles= SMALLER

Blood carries energy-rich molecules to the muscle Lets them do their work

In summary… Muscles help you move! They attach to bones with TENDONS Involuntary vs. Voluntary Muscles Striated vs. Non-striated Three types:

Skeletal Cardiac Smooth

FUN FACTS!

We have more than 630 muscles in our body.

More than 30 of our muscles are

in our face – that’s how we can

make different expressions

(happy, sad), talk and move our eyes around!

Scientists estimate that our eye muscles move more than 100,000

times a day!

STREET GYMNAST

WHAT MUSCLES LOOK LIKE

Your muscles need Glycogen (muscle sugar) in order to function. When the glycogen is broken down into

energy for the muscles a waste product called lactic acid is produced. A buildup of lactic acid decreases the muscles’ ability to contract and Muscle Fatigue sets in.

DO THIS:

Hold a book in each hand. Raise one arm straight out parallel to the ground and the other arm down at your

side.

Compare the feeling in each arm...

**keep track of how long you can hold the books for and which arm gets tired faster!

How long did you hold the book before fatigue got the better of you?

________ minutes ________ seconds

Which arm felt the fatigue the most? The straight arm or the arm by your side?

Which muscles experienced the most fatigue? Biceps triceps

deltoids pectoralis major