How Do Muscles How Do Muscles Work?Work?

Types of Movement.

Flexion:Flexion:

• The decreasing of an angle between bones.

• One of the bones of the joint moves towards the other bone.

Extension:Extension:

• The opposite action to flexion.

• When the angle is increased between two bones.

Abduction:Abduction:

• The movement of a limb or bone awayaway from the body.

• HINT – Abduction = to take away.

Adduction:Adduction:

• The movement of a limb or bone towardstowards the body.

• HINT - Adduction = to add to the body.

Rotation:Rotation:

• A turning movement around a central point.

Circumduction:Circumduction:

• A movement which causes part of the body to form a complete circle.

Muscles move by Muscles move by contracting.contracting.

What happens when muscles contract?contract?

A muscle has to pullpull for contraction to occur.

The muscle pulls on the bonepulls on the bone to make it move

Muscles cannot pushcannot push to make movement happen.

Muscles work in pairs.Muscles work in pairs.

The working muscles.

This is the muscle that contracts to allow movement.

The relaxing muscles.When one muscle contracts, another

relaxes to allow the movement to occur.

Muscles work in pairs.

E.g - The arm:

A flexed arm

How are muscles attached How are muscles attached to bones?to bones?

Via TendonsTendons..

Tendons join the voluntary muscles to the skeleton.

When the muscle contracts, the tendon pulls on the bone it is attached to and moves the bone.

Where do they attach?

Each muscle has an ORIGIN and an INSERTION.

The origin is where the tendon of a muscle is anchored to a fixed point on the skeleton.

The insertion is where the tendon is attached to the bone we want to move.

E.g – Biceps & triceps action:

Origin of bicep –

1. The top of the scapula

2. The glenoid cavity (in the shoulder).

Insertion of bicep –

1. Near the elbow, in the radius.

Turn to page 26 in your text books.

Use it to help you label the origin, insertion & muscles on the diagrams.

Stick these in your work books underneath the definitions of a tendon, origin & insertion.

Get out your planners.

To complete the sheet about muscles, how they move & how they are attached.

To be completed over the xmas holidays & brought into the 1st lesson back.

Don’t forget – a quick test that 1st lesson – so use it to help with revision!