The structure of the skeletal system:
Function of the skeletal system :
1 - Support : the skeleton keeps the body upright and provides a framework for muscles and tissue attachment.
2 - Posture : the skeleton gives the correct shape to our body
3 - protection : the bones of the skeleton protect the internal organs and reduce the risk of injury. For example, the cranium protects the brain, the ribs protect the hearts and
lungs, the vertebrae protects the spinal cord and the pelvis gives protection to the sensitive reproductive organs.
4 - Movement : the skeleton allows movement of the body as a whole and its individual parts. The bones forms joints and acts as levers, allowing muscle to pull on them to
produce movement. The bones of the skeleton provides surfaces for the attachment of muscles.
5 - Blood cell production : certain bones in the skeleton contain bone marrow which produces red blood cells, white blood cells and platelets. Examples : sternum, humerus and femur
6 - storage of minerals : the bones stores minerals such as calcium, iron , potassium and phosphorus, and release them into the blood when the body needs them.
Joints :
A joint is a place where two or more bones meet and is also called an articulation.
synovial joints ( freely moveable joints ) allow us the free movement to perform skills and techniques during physical activity.
Synovial joints have synovial fluid in the joint cavity that lubricates or 'oils' the joint so it moves smoothly. Synovial fluid is made by the synovial membrane.
In synovial joints, the ends of the bones are covered with cartilage ( called articular cartilage ) which cushions the joints and prevents friction and wear and tear between the bone
ends. Cartilage is a soft spongy connective tissue.
The bones is a synovial joints are connected by ligaments.
Ligaments are a type of connective tissue and are tough, fibrous and slightly elastic. They connect bone to bone to help keep the joint together. They stabilise the joints during
movement and prevent dislocation by restricting actions outsides the normal joint range.
The movement at a synovial joint is caused by the muscles attached across the joint. Muscles are
attached to bone by tendons. Tendons are very strong, inelastic connective tissues that allow a
muscle to pull on a bone to move it.
The four most important synovial joints are the elbow and shoulder joints in the arm and the knee and hip joints in the leg:
Elbow joint : A hinge joint ; Articulating bones are Humerus , radius and ulna. It allows bending ( flexion ) and straightening ( extension). Muscles which move the elbow are
biceps and triceps.
Knee joint : A hinge joint ; Articulating bones are femur and tibia. It allows bending ( flexion ) and straightening ( extension ). Muscles which move the knee are quadriceps and
hamstrings.
Hip joint : Ball and socket joint ; Articulating bones are pelvis and femur ( head of femur is 'ball' and the cup in pelvis in ' socket' ). It allows a range of movement in all directions.
many muscles are used to move the hip joint, including the gluteal.
Shoulder joint: Ball and socket joint ; Articulating bones are humerus and scapula. It allows a range of movement in all directions. Many muscles are used to move the shoulder joint,
including the deltoid.
Types of joint movement:
( Hinge join movements allow flexion and extension )
Flexion : bending a joint. This occurs when an angle of a joint decreases. For example, the elbow flexes when performing a biceps curl. The knee flexes in preparation for kicking a
ball.
Extension : straightening a joint. This occurs when an angle of a joint increases, for example when throwing a shot put. The take off knee extends when a high jumper takes off (
the other knee is flexed ).
Function of the skeletal system :
1 - Support : the skeleton keeps the body upright and provides a framework for muscles and tissue attachment.
2 - Posture : the skeleton gives the correct shape to our body
3 - protection : the bones of the skeleton protect the internal organs and reduce the risk of injury. For example, the cranium protects the brain, the ribs protect the hearts and
lungs, the vertebrae protects the spinal cord and the pelvis gives protection to the sensitive reproductive organs.
4 - Movement : the skeleton allows movement of the body as a whole and its individual parts. The bones forms joints and acts as levers, allowing muscle to pull on them to
produce movement. The bones of the skeleton provides surfaces for the attachment of muscles.
5 - Blood cell production : certain bones in the skeleton contain bone marrow which produces red blood cells, white blood cells and platelets. Examples : sternum, humerus and femur
6 - storage of minerals : the bones stores minerals such as calcium, iron , potassium and phosphorus, and release them into the blood when the body needs them.
Joints :
A joint is a place where two or more bones meet and is also called an articulation.
synovial joints ( freely moveable joints ) allow us the free movement to perform skills and techniques during physical activity.
Synovial joints have synovial fluid in the joint cavity that lubricates or 'oils' the joint so it moves smoothly. Synovial fluid is made by the synovial membrane.
In synovial joints, the ends of the bones are covered with cartilage ( called articular cartilage ) which cushions the joints and prevents friction and wear and tear between the bone
ends. Cartilage is a soft spongy connective tissue.
The bones is a synovial joints are connected by ligaments.
Ligaments are a type of connective tissue and are tough, fibrous and slightly elastic. They connect bone to bone to help keep the joint together. They stabilise the joints during
movement and prevent dislocation by restricting actions outsides the normal joint range.
The movement at a synovial joint is caused by the muscles attached across the joint. Muscles are
attached to bone by tendons. Tendons are very strong, inelastic connective tissues that allow a
muscle to pull on a bone to move it.
The four most important synovial joints are the elbow and shoulder joints in the arm and the knee and hip joints in the leg:
Elbow joint : A hinge joint ; Articulating bones are Humerus , radius and ulna. It allows bending ( flexion ) and straightening ( extension). Muscles which move the elbow are
biceps and triceps.
Knee joint : A hinge joint ; Articulating bones are femur and tibia. It allows bending ( flexion ) and straightening ( extension ). Muscles which move the knee are quadriceps and
hamstrings.
Hip joint : Ball and socket joint ; Articulating bones are pelvis and femur ( head of femur is 'ball' and the cup in pelvis in ' socket' ). It allows a range of movement in all directions.
many muscles are used to move the hip joint, including the gluteal.
Shoulder joint: Ball and socket joint ; Articulating bones are humerus and scapula. It allows a range of movement in all directions. Many muscles are used to move the shoulder joint,
including the deltoid.
Types of joint movement:
( Hinge join movements allow flexion and extension )
Flexion : bending a joint. This occurs when an angle of a joint decreases. For example, the elbow flexes when performing a biceps curl. The knee flexes in preparation for kicking a
ball.
Extension : straightening a joint. This occurs when an angle of a joint increases, for example when throwing a shot put. The take off knee extends when a high jumper takes off (
the other knee is flexed ).
