Bones and The Function of the Skeletal System

Bones and The Function of the Skeletal System

 

Below are the names of a few bones in the human body. You should be able to identify these bones on the human skeleton.

 

Functions of the skeletal system

There are six functions to the skeletal system.

Support:

• Hold bones together
• Hold muscles and organs into place
• Allow the human body to stay upright

Movement:

• The human body can create movement both as a whole and in parts. Our muscles contract and pull on the bones at every action which helps to create movement.

Protection:

• The human skeleton is formed to protect the vital internal organs of the human body. In addition, it also helps to limit the damage when impacted from other forces.
• g. Cranium – Helps protect the brain
• Ribs – Help protect heart and lungs
• Vertebrae – Helps protect the spinal cord.

Structural shape

• The human body comes in various shapes and sizes; this occurs due to the difference in bones in the body. E.g. Basketball players have different bones to a sumo-wrestler.

Mineral Storage

• The human body stores various minerals within the body which is released into the bloodstream when needed. E.g. Minerals in the body could include: Calcium, Phosphorus, Iron and Potassium.

Blood Cell Production

• Bone marrow of longer bones produce red and white blood cells
• Red blood cells carry oxygen to the working muscles when exercising providing energy.
• White blood cells help the human body fight infections.

 

Different types of Bones in the Human Body

There are four different types of the bones which help form the human body:

Short bone: This enables finer movements which are more controlled.

Long bone: This enables larger and grosser movements.

Flat bone: These bones help protect the vital organs.

Irregular bone: These bones vary in shape and sizes and have many different purposes, one of which is protecting nerve tissues in the body.

 

Exam Questions:

• Flat bones in the human body provide protection.

Name 2 flat bones in the human body and suggest how these bones provide protection during sporting activity.

 

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• State 4 functions of the human body.

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• Name 5 bones in the legs of the human body.

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• How does the human skeleton ‘support’ the body?

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Joints and Movements

• A ‘joint’ is where two or more bones meet to allow movement to take place.
• Synovial fluids are the most common type of joints in the body. This allows smooth movements to take place where two or more bones meet. (See diagram below for synovial joint)

 

Types of Joints

Types of Joints

• Hinge Joint:

• Located at the knee, elbow and ankle. They allow movement in one direction.

• Ball and Socket Joint:

• Located at the shoulder and hip joint. Ball and Socket joint is made up of one round head bone which can insert itself into an area of another bone.

• Pivot Joint:

• Located in the neck (Top). Pivot joint usually allows rotational movements.

• Condyloid Joint:

• Located at the wrist. Condyloid joint allows you to move your wrist from side to side, whilst also allowing flexion and extension.

 

Types of Movements

• Flexion:

  The angle between the bones at a joint will decrease. E.g. Bicep Curl

• Extension:

  The angle between the bones at a joint will increase. E.g. High jump knee ‘extension’ at take-off.

• Adduction:

  Movement where body parts are moved back towards the body. E.g.

• Abduction:

  Movement where body parts are moved away from the body. E.g.

• Rotation:

  Movement when your body part is turned along its axis. E.g. Bowling in cricket

• Circumduction:

  Body part moving in a circular motion. E.g. Tennis serve.

• Plantar Flexion:

  Movement that shows your foot pointing down towards the ground. E.g. Gymnastics pointing toes.

• Dorsi-Flexion:

  Movement that shows your foot pointing upwards. E.g. Kick ups.

 

Exam Questions:

• Using an example of a sport of your choice, identify two movements that can occur at a hinge joint.

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• Where in the body can you locate the hinge joint?

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• Describe the movement ‘Flexion’? Can you give an example of a sport where flexion is used?

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• Label the diagram below.

 

Muscles, Actions and Contractions

Below are the names of some muscles you should know. These should be memorised before your exams.

 

What is a ligament?

• Ligaments connect bone to bone.

What is a tendon?

• Tendons connect muscles to bones. It is a strong piece of elastic tissue.

Antagonistic Muscle Pairs/Actions

• At a joint, we have two or more muscles working together. They work opposite to one another which allows movement to be made. Muscle tends to pull the bone which allows one to contract and one to relax.

Muscle Actions

• Agonist is known as the prime mover which allows the muscle to contract.
• Antagonist is known as the secondary mover which allows the muscle to relax.
• g. During a bicep curl, the bicep contracts and tricep relaxes. This means that the bicep is the agonist and the tricep is the antagonist.

 

Muscle Contractions

There are two types of muscle contractions:

Isotonic contraction

• which is where the muscle changes length as soon as it contracts.
• Concentric contraction which is where the muscle shortens its length.
• Eccentric contraction which is where the muscle lengthens however this is occurred for ALL downwards movements.

Isometric contraction

• which is where the muscle remains the same length whilst it is contacting. This can occur at the start of a 100m race when the athlete is starting ‘off the block’.

 

Exam Questions:

• Explain what muscles are used during the bicep curl and how do they produce the movement? (Think about muscle actions)

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• Explain what muscles are used during the downward phase of a bicep curl and how do they produce the movement? (Think about muscle actions)

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• Describe the term isometric contraction?

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• What is a tendon? ………………………………………………………………………………………………………………..………………………………………………………………………………………………………………..

 

• What is a ligament?

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