NCEA Year 11�Student Work Book�5 Credits�

1.2 Demonstrate understanding of the function of the body as it relates to the performance of physical Activity

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Skeletal System

Different types of Bones

Long

Short

Irregular

Small, round and Flat

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• Long bones found in the upper arm and leg are:
• Short bones found in our ankles or wrists are:
• Flat bones can be found:
• Irregular bones that make up the :

Function of our Bones

Our bones have 5 major functions. Explain each function:

• Protection - the cranium and ribs protect the brain and vital organs in the chest.
• Shape - gives shape to the body and makes you tall or short.
• Support - holds your vital organs in place when playing sport. The vertebral column holds the body upright.
• Movement - muscle are attached to bones, which are jointed. When the muscles contract the bones move.
• Blood production - red blood cells (to carry oxygen) and white blood cells (to protect against infection) are produced in the bone marrow of some bones.

Lets put the bones into the four categories

Joints

Definition:

Where two or more bones meet. There are three different types of joints .

1. No movement
2. Little movement
3. Most Movement

Types of Synovial Joints

Freely Moveable (Synovial) joints can be divided into six groups depending upon the way they move.

Key:

• Ball and Socket Joint
• Hinge Joint
• Pivot Joint

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• Saddle Joint
• Condyloid Joint

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Hinge Joints

• HINGE JOINTS allow extensive flexion and extension with only a small amount of rotation.

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• The joint is made by the joining of two bone ends which have smooth surfaces. They are shaped to move against each other with minimum friction.

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Examples of Hinge Joints: Elbow and Knee Joints

Pivot Joint

• PIVOT JOINTS allow only rotation.

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• A “peg” which fits into a “ring” formed by the other bone.

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• There is pivot joint at the top of the spinal column, between the axis and atlas bones of the neck. This allows us to turn, raise and lower our heads – this is crucial in controlling balance and maintaining awareness.

Ball and Socket Joints

• Of all the joints in the body, the BALL AND SOCKET JOINT allows the greatest range of movement
• In this type of joint, one end of the bone is shaped like a ball, and it fits into a hollow socket at the end of another joint.
• Held together by ligaments and tendons

Two main Ball and Socket Joints: Shoulder and hip joints

Gliding Joints

• GLIDING JOINTS allow flexion and extension through a slight gliding motion between the ends of small bones such as hands and feet.
• These small bones can move over one another to increase the flexibility of the hands and feet.
• Strong ligaments link them together and stop them moving to far.

Condyloid Joint

Condyloid joints consist of an oval-shaped end of one bone fitting into a similarly oval-shaped hollow of another bone (Figure 5). This is also sometimes called an ellipsoidal joint. This type of joint allows angular movement along two axes, as seen in the joints of the wrist and fingers, which can move both side to side and up and down.

Types of Joint Movement

• There are six different kinds of movement the joints can allow
• These are:
• Extension
• Flexion
• Abduction
• Adduction
• Circumduction
• Rotation
• Plantar/ Dorsi lection

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EXTENSION

Movement that moves two

bones away from each other

(angle increases)

FLEXION

Movement that brings two bones closer together (angle decreases)

ABDUCTION

Movement of the bone away from the middle of the body

Rotation: This is a turning or rotational movement of a limb or body part.

ADDUCTION

Movement of the bone towards the middle of the body

DORSI FLEXION

Pointing the toe up so the angle between tibia anterior and the metatarsals decreases around the ankle joint

PLANTAR FLEXION

Pointing the toe down so the angle between tibia anterior and the metatarsals increases around the ankle joint

The knee (HINGE JOINT) is used when flexing (bending) and extending (straightening) the leg to kick a football

Muscular System

Muscle action

Along with the bones of the skeleton, muscles produce movement.

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As muscles contract , they shorten and produce movement by pulling the bones in different directions. The direction will depend on the type of joints the muscles act on (see section on Joints).

Muscles are attached to bones by TENDONS

Video

How the Muscles Move

• Muscles can only pull. To make a joint move in two direction, you need two muscles that can pull in opposite directions.
• Antagonistic muscles are pairs of muscles that work against each other. One muscle contracts (agonist, or prime mover) while the other one relaxes (antagonist) and vice versa.
• The origin is where the muscle joins the fixed bone. The insertion is where it joins the moving bone. On contraction, the insertion moves towards the origin.

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Copyright 2005

Victory Physical Education

Remember what ANTAGONISTIC PAIRS Do!!!!!

Agonist and Antagonist Muscles Summary

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Agonist / prime mover – muscle directly responsible for the movement at a joint.

Antagonist – muscle that is relaxing and has the opposite action to the agonist.

Types of movement?�muscles being used?�Agonist, Antagonist?

Preparation stage

Release stage