Chapter 28 (the muscular system)

Muscle Teams

- When muscles contract they become shorter and thicker. -Skeletal muscles that bend joints are called Flexors. -Skeletal muscles that straighten out the joints are called extensors. -When a flexor muscle is partnered with an extensor muscle they work as a team to bend and straighten joints. -Biceps and triceps of the upper arm are an example of a muscle team.

Skeletal Muscle Tissue.

-Attaches to the bone to permit movement. -Skeletal muscle movement is voluntary. -Skeletal muscle cells are long and strong and are arranged in bundles enclosed in tough connective tissue sheaths.

6 Functions of Skeletal Muscles?

-Contractions provide heat. -Contractions permit movement -Hold the trunk and head erect. -Protect blood vessels and nerves. -Help blood flow feature to the heart. -Provides protection padding for internal organs.

Smooth Muscle Tissue.

-Delicate muscle cells found throughout the internal organs of the body. -Smooth muscle tissue is involuntary and occurs constantly in functions such as breathing, peristalsis, blood vessels contraction, and pupil dilation.

Muscle Sheath

-Membranes that separate the muscle groups to prevent friction from movement.

Muscle Tone

-Most skeletal muscles are partially contracted at all times so that the body remains erect. -This constant state of contraction is known as muscle tone.

Cardiac Muscle Tissue.

-Muscle tissue found on,y I. The heart. -Arranged in a continuous network without sheath separation. -When once cell receives the signal to contract, all neighboring cells are stimulated and they contract together.

Muscle Activity and Heat Protection?

-Muscles use stored glycogen as an energy source. -As this fuel is used, heat is produced and warms the body.

Meaning of terms: origin and insertion.

-Origin: skeletal muscles join bones that meet at the joints, one of the bones becomes the anchor which the muscle hits it's origin. -Insertion: the bone moved becomes the insertion end of the muscle.

Bursae

-Sheath that is shaped like a sac and has a slippery fluid lining that acts as a cushion to minimize pressure and friction.

Spasm

A painful contraction of a muscle that will not relax.

Atrophy.

A progressive wasting of a muscle tissue from the lack of use.

Hiccough

A spasmodic contraction of the diaphragm.

Fascia

A though membrane or sheath attachment.

Dystrophy

Congenital disorders that result in progressive wasting away of skeletal muscle.

Strain

Excessive stress on a skeletal muscle.

Peristalsis.

Involuntary contraction of smooth muscle that results from alternate contraction and relaxation of the layer of the smooth muscle.

Contracture

Permanent shortening or contraction of muscle.

Sphincter Muscle.

Smooth, donut-shaped muscles that pinch shut intermittently to control the flow of blood, food, or liquid.

Anchor.

The origin of a muscle.

Abduction

To move an extremity away for the body's center.

Adduction

To move an extremity toward the body's center.