Skeletal and muscular system

Functions of the skeleton

Functions of the skeleton

• Shape and support

• Movement

• Protection

• Blood production (red blood cells)

Examples of long bones

• Femur

• Humerus

• Clavicle

Examples of short bones

• Carpals

• Tarsals

Examples of flat bones

• Scapula

• Sternum

• Cranium

Examples of irregular bones

• Vertebrae

Types of joints

• Fixed (fibrous)

• Slightly moveable (cartilaginous)

• Freely moveable (synovial)

Type of synovial joint

• Ball and socket

• Hinge

Examples of fixed joints

Cranium

Examples of slightly moveable joints

Vertebrae

Examples of freely moveable joints

Hip

Elbow

Components of a synovial joint

• synovial membrane

• synovial fluid

• joint (fibrous) capsule

• cartilage

• ligaments

Flexion

Bending at a joint

Extension

Straightening a joint

Abduction

Movement away from the body

Adduction

Movement towards the body

Rotation

Limb moves in a circular motion around a fixed point

Circumduction

Limb moves in a circle

Plantar flexion

Pointing of toes

Dorsiflexion

Foot moves towards the shin

Tendon

Connects muscles to bones

Ligament

Attaches bone to bone

Muscle that contracts

Agonist

Muscle that relaxes

Antagonist

One muscle of the pair contracts to move the body part, the other muscle in the pair then contracts to return the body part back to the original position

Antagonistic pair

Isotonic contractions

When a muscle contracts and changes length

Concentric

Muscle shortening

Eccentric

Muscle lengthening

Isometric contraction

Muscle producing tension but staying the same length

Muscle fibre types

Fast and slow twitch

Fast twitch muscle fibres

• Contracts quickly

• Anaerobic

• Low fatigue tolerance

• Small, sudden bursts

Slow twitch muscle fibres

• Contracts slowly

• Aerobic

• High fatigue tolerance

• Sustaining energy source