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Functions of the Skeleton

1. Movement- muscles pull on bones to move.
2. Protection - i.e skull protects brain, ribs protect heart and lungs.
3. Support - keeps our shape.
4. Bone Marrow - blood cells are made in here.

[Diagram of Human Skeleton].

The scapula is found by your shoulder (shoulder-blade). The humerus is the upper bone of your arm. The ulna is the inner bone of your lower arm and the radius is the outer bone of your lower arm. The femur is the upper bone of your leg and the tibula is the inner bone of the lower leg and the fibula is the outer bone of the lower leg.


A joint is where two bones meet.

Types of Joints

Ball and socket joint e.g Shoulder (humerus and scapula).
Ball and socket joint e.g Hips (femur and pelvis).

[Diagram of Joint].

Ball and Socket joints allow movement in many planes.

Hinge joints e.g elbow(humerus, radius and ulna).
Hinge joints e.g knee (femur, tibula and fibula).

Hinge joints allow movement in one plane.

Structure of a Joint

Synovial membrane - produces synovial fluid.
Synovial fluid - lubricates the joint.
Cartilage - acts as a shock-absorber - cushions the end of the bones.
Ligaments - holds the bones together in the joint.

Movement at Joints

Each joint has a pair of opposing antagonistic muscles.
When one contracts, the other relaxes.

To bend the arm, the biceps contracts and the triceps relaxes. To straighten the arm, the biceps relaxes and the triceps contracts.
Having an opposing pair of antagonistic muscles gives us better control of the movement.
Muscles are attached to bones by tendons.
It's important that tendons are inelastic (not stretchy) so they can transfer the pull of the muscle to the bone.

[Diagram of tendons].


Bones consist of:
a) Living Cells - which make bone slightly flexible.
b) Calcium Phosphate - which makes bones hard.

The Need for Energy

A person's energy requirements depend on their age, sex and activity /exercise level.

Human Breathing System

[Diagram of lungs].

[Diagram of alveoli].

[Diagram of Alveoli].

Useful features: Thin-lining allows fast diffusion. Large surface area - allows fast diffusion. Layer of Moisture - allows O2 to dissolve. Good blood supply - O2 picked up quickly.

Human Breathing System

Air enters through the nose where it is warmed and there are hairs and mucus to trap dust and germs. It passes down the windpipe (or Trachea) and then down one of the Bronchial tubes. The bronchial tubes divide into smaller and smaller tubes called bronchioles. All of these air passages are held open with rings of cartilage.
At the ends of the bronchioles are the Air sacs or alveoli. These are surrounded by many blood capillaries and have very thing-linings (only one cell thick). They also contain a layer of moisture.
Oxygen from the air in the sac dissolves in the layer of moisture and diffuses through the thin lining into the blood capillaries.
Carbon dioxide passes in


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