Myology

The study of the muscular system.

Muscles make up...of the total body weight.

45% of the total body weight.

Contractility

The unique ability of muscles to contract or shorten in length to cause movement.

Prime Mover

The muscle which is primarily responsible for a desired action or movement.

Antagonist

Has the opposite effect of the prime mover.

Skeletal Muscle

This muscle tissue attaches to the bones of the skeleton and through contraction, it creates movement by pulling on bones. Most of the muscle in the human body is this tissue. It is also striated.

Smooth Muscle

Involuntary muscle tissue that is found in most organs known as visceral muscle. It is non-striated.

Cardiac Muscle

The type of tissue found in the heart that is involuntary and striated.

Involuntary

Automatic, works on its own.

Voluntary

Can be made to contract by voluntary control.

Striated

It contains dark stripes.

Non-striated

Does not contain any dark stripes.

Muscle tissues are attached to the...

Periosteum of the bone, which is the bones outer layer. They are attached to the periosteum by tendons.

Tendons

Strong, dense cords of connective tissue. They attach muscle to bones (muscle to muscle sometimes) and can often cross over an articulation in order to pull on the bones forming the joint, bringing them toward each other.

Origin

The end muscle that is attached to the less moveable of "fixed" bone. Located at the proximal end. Movement at this point is minimal.

Insertion

End of the muscle that is attached to the more moveable bone. Located at the distal end. Movement at this point is much greater.

Body

The main, fleshy portion of the muscle that is also known as the belly of the muscle.

Muscle Fibers

Long, cylindrical, microscopic cells that create the muscles.

Myofibrils

Consist of finer filaments that are made up of specalized proteins.

Tonic

A partial muscle contraction that allows for a relatively constant amount of tension in a muscle so that it can hold a body [art in its proper position.

Twitch

Rapid, jerky contraction that play no major role in normal body activity.

Tetanic

More sustained contractions, where muscle fibers are unable to relax between stimuli occurring at a more rapid rate.

Isotonic

The muscle shortens and pulls on another body part, such as a bone, in order to create movement.

Isometric

A type of contraction that involves a constant tension put upon a muscle, but little or no movement occurs.

Criteria for Naming Muscles:

Shape, Location, Direction of the muscle fibers, Size, Number of divisions that make up the muscle, Point of attachment, Whether the muscle is superficial or deep, The action the muscle provides.

Abduction (Abductors)

Moving away from the midline of the body.

Adduction (Adductors)

Moving toward the midline of the body.

Flexion (Flexors)

Decreases the angle between the two bones by bending a body part.

Extension (Extensors)

Increasing the angle between bones as in straightening a body part.

Pronation (Pronators)

Movement of the palm of the hand from a forward or upward position to a backward or downward position.

Supination (Supinators)

Movement of the palm of the hand from a backward or downward facing position to a forward or upward position.

Elevation (Levators)

Lifting up a body part.

Depression (Depressors)

Lowering of a body part.

Rotation

Movement of a bone around its longitudinal axis.

Circumduction

Swinging a body part in a circular manner.

Constriction

The squeezing closed of a body orifice.

Dilation

The widening or opening of a body orifice.

Protraction

Forward movement of a body part.

Retraction

Backward movement of a body part.

Eversion

Outward turning of the sole of the foot.

Inversion

Inward turning of the sole of the foot.

Zygomaticus Major

Smiling muscle -- it draws the corners of the mouth outward and upward.

Orbicularis Oris

Kissing muscle -- involved in puckering the lips.

Buccinator

Trumpet muscle -- located in the cheek muscle, it helps puffs the cheeks out.

Frontalis

Helps raise the eyebrows.

Risorius

False smiling muscle -- draws the corners of the mouth lateral as in tension or a false smile.

Platsyma

Pulls the lower lip down and back.

Temporalis

Muscle of mastication attached to the temporal bone.

Masseter

Muscle mastication directly involved in chewing.

Internal Pterygoid and External Pterygoid

Attached to the wind-shaped portion of the sphenoid bone.

Mastication

Muscles involved in chewing and grinding food.

Aponeurosis

Any broad, flat tendon in the body.

Galea Aponeurotica (Occipitofrontalis or Epicranium)

A strong tendinous sheet of tissue over the top of the cranium that connect the frontalis muscle in the forehead area and the occipitals muscle in the back of the head.

Sternocleidomastoid Muscle

A muscle in the neck that helps move the head. It is also the anatomical guide for locating major blood vessels in the neck.