Muscular System

By: Emily Brosten

Stephanie Elhard

JAMES VALLEY VOCATIONAL TECHNICAL CENTER

Introduction

• 1. 600 muscles in the body

• 2. Muscles are ~ made of bundles of muscle fibers which are held together by connective tissue.

• 3. When muscle fibers are stimulated by nerves ~they contract or become short and thick.

• Voluntary ~ you can willfully control muscles

*facial expressions, chewing, swallowing, and movement of the head

• Involuntary ~ function without the person thinking about contracting the muscles. *digestive system, heart muscles, and blood vessels**Some muscles are both voluntary and involuntary ~ example eye blinking

THREE TYPES OF MUSCLES

• 1. Cardiac muscles ~ cells are packed so closely together its hard to tell one cell from another. ~forms walls of the heart ~contact to circulate blood ~involuntary

• 2. Visceral/Smooth muscles~found in internal organs of the body

*digestive, respiratory system, blood vessels, and eyes. ~muscles contract to cause movement in these areas ~involuntary function without the person thinking about contracting the muscle

• 3. Skeletal~ most abundant muscle

~attached to bone~causes body to

move ~voluntary

FUNCTIONS OF SKELETAL MUSCLES

• 1. Attaches to bones to provide voluntary movement.

• 2. During contractions provide heat and energy.

• 3. Helps maintain posture.

• 4. Some protect internal organs.

SKELETAL MUSCLES ATTACH TO BONES

IN VARIOUS WAYS

• 1.Tendon ~ strong, tough connective tissue cord, connect muscle to bone *Achilles Tendon (attaches to calf muscle and heel bone) *lumbodorsal fascia (surrounds the deep muscles of the back and trunk)

• 2. Fascia ~ tough, sheet-like membrane that covers and protects tissue*lumbodorsal fascia (surrounds the deep muscles of the back and trunk)

• 3.Origin ~ When a muscle attaches to the bone, the end doesn’t move.-usually attaches closer to the trunk of the body-where the muscle begins

• 4. Insertion ~ the end of the muscle that attaches to a bone that moves -where the muscle ends

CHARACTERISTICSOF

MUSCLE TISSUES

1. Contractability ~ ability to shorten and thicken (when muscles work they contract that is they get shorter and thicker)

• 2. Extensibility ~ ability to stretch (when muscle is relaxed it becomes longer and thinner) *some muscles work while others relax *

• 3.Elasticity ~ ability to return to original length

• 4. Irritability ~ability to respond to stimulus

• 5. Tone ~ slight tension in the muscles at all times, even at rest

MOVEMENTPERFORMED

BYMUSCLES

• 1. Adduction ~ moving a body part toward the midline

• 2. Abduction ~ moving a body part away from the midline

• 3.Flexion (Flexor) ~ decreasing the angle between two bones and body part

• 4. Extension ( Extensor) ~ increasing the angle between two bones and body part

• 5. Rotation ~a circular motion which turns a body part on its axis

• 6. Sphincters: ring like muscles that close body openings–example: rectum

• 7. Levators: lift a part of the body

• 8. Depressors: lower a part of the body

• 9. Supination: the act of rotating the arm so the palm of the hand is upward.

• 10. Pronation: the act of rotating the arm so the palm of the hand is turned downward.

Terminology

• Muscle tone: muscles that are partially contracted at all times, even when they may not be in use.

• Contracture: severe tightening of a flexor muscle that results in bending of a joint.

• Myology: my/o = muscles» ology = study of

– the study of muscles

MYOLOGY

The Study of Muscles

CHARTS