Holiday Task F5

TO: PUAN MAHADIAH MUDA via gmail: date: 14 March 2011

TASK 2:

Explain how the bones, skeletal muscles,tendons and joints bring out movement in the arm or leg.

We can make an example which is the hinge joint between the humerus and radius-ulna acts as a fulcrum and the object is the load that needs to be lifted. The effort is provided by the biceps which contract to produce the force needed to lift the object. Joints are places where two bones meet and ligaments hold the two bones together.The bones of the skeleton are hard and act like levers. When muscles pull on these levers, they produce movements. In order for the arm to be upwards, the biceps needs to contract while the triceps relaxes. It is the contraction of muscles that produces the movement of the arm. This pair of muscles, called antagonistic muscles,vwork together to coordinate the movements at the skeletal joints. This means that when one muscle contracts (shortens),the other relaxes and stretches. One muscle pulls the bone in one direction while the other pulls it in the opposite direction. Hence, when the biceps contracts, the tendon transmits the pulling force produced by the contraction to the forearm. At the same time, the tricep relaxes. As a result, the elbow

joint bends and the forearm moves upwards

Answer provided by :

FARAHNABILAHBTAHMAD
5 Gastisia

Note: Sentences in RED are the ones who scored marks. 9/10- Good.