Explain The Skeletal And Muscular System

Submitted By brownmv
Words: 1997
Pages: 8

Pe Notes

The skeletal and muscular systems

the average human has 206 bones in their body, they divide into two different parts, the axial and the appendicular skeleton. Bones such as the sternum and the ribs are part of the axial skeleton. The femur and Ulna are part of the appendicular skeleton.

Bone is made up of collagen fibres.
There are 5 types of bone in the skeleton that are classified according to there shape.
Long Bone - longer than it is wide and consists of a shaft this is called the diaphysis the two ends are called epiphysis.
The epiphysis is covered by articular cartilage - acts as a shock absorber and prevents friction.
Growth plate - promoting longitudinal bone growth until physical maturity.
Bones also contain cavities that are filled with bone marrow which generates new blood cells.

Synovial Joints

The structure of a synovial joint

Ligament - a band on fibrous tissue - to connect bone to bone.
Synovial fluid - a slippery fluid with consistency of egg white that is contained within the joint cavity - to reduce friction between the articular cartilage in the joint. articular cartalidge - glassy-smooth cartilage that is spongy and covers the end of the bones in the joint - to absorb shock and to prevent friction between the ends of the bone in the joint joint capsule - a tough fibrous tissue that has two layers, with the fibrous capsule lying outside the synovial membrane

Movements of synovial joints

the movements of any particular joint are possible because of its structure and the skeletal muscles that contract to pull the bone into a different position.
When the muscle contracts across a joint, one point of attachment is pulled towards the other causing joint movement.

Type of synovial joint examples from skeleton description mobility
Ball and Socket shoulder hip a ball shaped head of one bone articulates with a cup like socket of an adjacent bone. movement can occur in three planes. this joint allows the greatest range of movement.
elbow knee ankle a cylindrical protusion of one bone articulates with a trough - shaped depression of an adjacent bone. movement is restricted to one plane. this joint allows bending and straightening only.

Anterior posterior superior inferior medial lateral Main Movement

Flexion and extension

Flexion of a joint makes a body part move in a forward direction extension of a joint makes a body part move in a backwards direction

Horizontal flexion and horizontal extension

horizontal flexion and horizontal extension are movements of ball and socket joints. horizontal flexion occurs when the shoulder is already flexed and moves towards the body. horizontal extension occurs when the shoulder joint with the arm parallell moves away from the body.

Adduction and Abduction

adduction of a joint makes a body part move towards the midline of the body abduction of a joint makes the body part move away from the midline of the body


circumduction of a joint makes a body part move from the anatomical position, the joint performing circumduction stays still while the furthest end of the body part moves in a circle.

Pronation and supination

pronation of the radio-ulna joint makes the palm move to face backwards or downwards supination of the radio-ulna joint is with the palm facing forwards or upwards.

Lateral Flexion

lateral flexion involves the bending of the spine sideways as you might do as part of a warm up to mobilise the spine.

Dorsiflexion and plantar flexion

Dorsiflexion of the ankle joint makes the foot move towards the shin (walking on your heels)
Plantar flexion of the ankle joint makes the foot move away from the shin (walking on tiptoes)

Joint movements possible wrist flexion and extension radio-ulna pronation and supination elbow flexion and extension shoulder flexion and extension horizontal flexion and horizontal extension

The muscular system

600 muscles in the human body. muscles are attached to