Movement Mechanism and Roles Terms you must learn

Movement Mechanism and Roles

Terms you must learn n Ligament – connects bones n Joint – where bones meet n Tendon –connects muscle to bone n Synovial Fluid – acts as a lubricant

Joints, Muscles and Movement …Muscles n Muscle tissue consists of elongated cells or fibres held together by connective tissue n There are 3 types of muscles in the body of a mammal q q q Involuntary (smooth) muscle Cardiac (heart) muscle Voluntary (skeletal) muscle

Muscle… n Involuntary muscle q Contractions of these muscles are usually slow and rhythmical n q E. g. as in the digestive tract Smooth muscle also control the movement of the n n n Iris of the eye The walls of the blood vessels The walls of the bladder

Muscle… n Cardiac muscle q q This type of muscle is found only in the heart It has special properties n n It contracts without becoming fatigued for the whole life of the organism It does not need to be stimulated by hormones or nerves to make it contract

Muscle… n Voluntary muscle q q q Also called skeletal muscle because they are attached to the bones. They are under conscious (voluntary) control Tendons attach muscle to bone n They are made of strong elastic fibres

Action at movable joints n Movements of the body occur when contractions of voluntary muscles attached to the bones of the skeleton take place n Each muscle is attached at 2 points and crosses one or more joints which move when the muscle contracts

Action at movable joints… n When a muscle contract, it becomes shorter and exerts tension between its 2 points of attachment q q One of these points remains fixed which is the origin of the muscle The other end moves as a result of this tension and is called insertion

Action at movable joints… n Muscles can only contract and relax q q n Contraction – muscles get shorter Relaxation – muscles lengthen All muscles act in pairs q q When one contracts the other relaxes The contracting muscle lengthens the antagonistic muscle which is relaxed n n This produces movement of a bone in one direction When the reverse happens the bone is moved in the opposite direction

Action at movable joints… n There are times when both sets of muscle in an antagonistic system contract at the same time q This causes the joint to lock at a particular angle.

Action at movable joints… n n During movement bones act as levers Each joint acts as a pivot q n n Movement takes place at the joint A force is applied when the muscle contracts (effort) The effort acts against another force (the load)

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