Muscular system

involuntary muscle-

work automaticaly and constantly

only found in the walls of the heart

muscles that you cannot control

found in the walls of the intestines and in the blood vessels

they have to keep contracting to allow crucial body functions to continue

also known as smooth muscles

voulntary muscles are attached to the skeleton by TENDONS.

The point where the msucle is attached to he fixed/stable bone is called the origin.

The point where the muscle is atttached to the moving bones is valled the insertion.

Make up the majority of muscles in the body.

Attached to the skeleton.

They are under our conscious control and move through conscious effort.

in order to enable a pulling movement in both directions muscles need to work in pairs.

the muscle which is contracting os known as the prime mover or agonist

the muscle which is relaxing is known as the antagonist

muscle that work in pairs are said to work antagonistically

bending the arm at the elbow is an example of flexion taking place

the muscle responsible for flexion at the elbow is the bicep

the bicep is the prime mover or the agonist as it produces the desired joint movement.

in order for the muscle to shorten when contracting the tricep muscle must lengthen

the tricep in this instance is known as the antagonist since the action is opposite the bicep

flexors - muscles that bend limbs at a joint by contracting

extensors - the muscles that work with and against the flexors and straighten a limb at a joint by contracting

adductors - the muscles that move a limb towards the body 

abductors - the muscles that move a limb away from the body

there are two types of muscular contrations

-isometric contractions

-isotonic contractions

when muscles contract but stay in a fixed position niether shortening or lenthening

example - scrum in rugby

               - tug of war

when muscles contract and work over a range of movement

muscles contract with visible movement

there are two types

- concentric - shorten

- ecentric - lengthen

concentric - when the muscle shortens. It also tends to bulge e.g. Biceps in the arms

ecentric - when the muscles gradually lengthens and returns to its normal length and shape

working muscles produce heat  

lactid acid production during anearobic exercise causes cramp

cardiac muscle works harder 

more oxygen is needed in the working muscles

muscles contract and relax 

muscles becoem fatigued as the ability to use oxygen becomes less effecient 

muscles will incresse in size and strenth as a result of regular exercise. An increase in muscle size is called hypertrophy

regular exercise willl increas the muscular systems resistance to fatigue 

when muscle looses its size due to inactactivity or injury it is called atrophy