Muscular System
Outline
1.
Skeletal – Voluntary; responsible for
movement.
2.
Smooth (Visceral) – Involuntary;
movements of respiration, digestion, and
urination.
3.
Cardiac – Involuntary; heart muscle.
3 Types of Muscle Tissue

Aid in movement

Provide and maintain posture

Protect internal organs

Provide movement of blood, food and waste
products throughout the body

Open and close body openings

Produces heat
Functions of Muscle
Contraction = movement
and shortening of muscle
Tonus = slight continuous
contraction
Flaccid = soft, not
contracted
Vocab
1.
Mechanically – You telling your brain to
activate a muscle. EX: Holding your pencil
to write these notes.
2.
Electrically – Using a machine to activate a
muscle. EX: IFC in ATR.
3.
Chemically – Drugs that activate a muscle.
EX: Narcotics will dilate your pupils.
Muscle stimulation
Irritability or excitability: ability to
respond to a stimulus
 Contractility: ability to shorten

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Extensibility: ability to stretch and
lengthen

Elasticity: ability to recoil to its resting
length
Vocabulary

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
Makes up 40 % of body weight
Increase in size and weight with exercise
Named according to:
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Location
Related bones
Shape
Action
size
Looks striated under microscope (fibers run
parallel)
Tendons attach muscle to bone
Skeletal Muscle
Sarcomere:
- Causes contraction
- Made up of actin and mysosin
Units of Muscle Fibers
1.
Origin: attached to the less movable part of bone
2.
Insertion: attached to the more movable part of
the bone
Body: middle part of the muscle
3.
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Also called a ?
3 parts of Skeletal muscle

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Flexion = decreasing joint angle
Extension = increasing joint angle
Abduction = movement away from
midline
Adduction = movement towards the
midline
Pronation = turning palms down
Supination = turning palms up
Movement Terms

Lines organs

Makes up walls of blood vessels

In the digestive system

Smooth – has not striations

Contracts when stimulated

Controlled by the autonomic nervous system
Visceral Muscle

Only in the heart

Striated muscle

Involuntary control
Cardiac Muscle
Sliding Filament Theory of muscle
contraction
Sliding Filament Theory of muscle
contraction
Types of Muscle Contraction
Isotonic: muscle shortening produces
movement through a full range of
motion
Muscle tone (Tonus) : partial
contraction, maintains posture
Isometric: no shortening of muscle
Tetanic: continued contraction of
muscle
Fibrillation; uncoordinated contraction
of muscle fiber
Convulsion; groups of muscles
contract in abnormal manner
Spasms: involuntary contractions