Muscular SystemVictoria EmiJorgeJonathan

Muscular System Facts . There are over 600 muscles that make

up the muscular system . Muscles are bundles of fiber held

together by connective tissue . There are 3 main kinds of muscle,

Cardiac, Visceral, and Skeletal

Cardiac muscle: forms the walls of the heart and contracts to circulate blood

Visceral muscle contracts to cause movement in these organs.

Visceral (smooth) muscle is found in the internal organs of the body such as those of the digestive and respiratory systems, and the blood vessels and eyes.

Cardiac and Visceral muscle are involuntary, meaning they function without conscious thought or control.

Skeletal muscle is attached to bones and causes body movement

Skeletal muscle is voluntary because a person controls its action.

Properties & Characteristics Excitability-irritability, the ability to respond

a stimulus such as nerve impulse Extensibility- the ability to be stretched Elasticity- allows the muscle to return to its

original shape after it has contracted or stretched

Contractibility- muscle fibers that are stimulated by nerves contact, or become short and thick, which causes

movement

Action and Movement Adduction- moving a body part toward the

midline Abduction- moving a body part away from the

midline Flexion- decreasing the angle between two

bones, or bending a body part Rotation- turning a body part around its own axis;

for example, turning the head from side to side Extension-Increasing the angle between two

bones, or straightening a body part  

Skeletal muscles attach to bones in different ways such as tendons and by fascia.

Tendons: are strong tough connective tissue cords

Fascia: is a tough sheet like membrane that covers and protects the tissue.

An Origin is when a muscle attaches to a bone and the end does not move.

The end that does move when the muscle contracts is called the Insertion.

Muscles are partially contracted at all times, even when we don’t use them.

They are always in a state of muscle tone (state of readiness to act)

It’s important to continuously use our muscles because lack of muscle tone can give as paralysis.

Our muscles can shrink in size and lose strength with lack of muscle use, you can also develop contracture, a painful severe tightening of a flexor muscle resulting in bending of a joint.

Thank you for your time!