Muscular System
Outline
1.
Skeletal
2.
Visceral
3.
Cardiac
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
Flacid = soft, not
contracted
Vocab
1.
Electrically
2.
Mechanically
3.
Chemically
Muscle stimulation

Irritability or excitability: ability to
respond to a stimulus

Contractility: ability to shorten

Extensibility: ability to stretch and
lengthen

Elasticity: ability to recoil to its resting
length
Vocabulary
Makes up 40 % of body weight
 Increase in size and weight with exercise
 Named according to:

◦
◦
◦
◦
◦
Location
Related bones
Shape
Action
size
Looks striated under microscope
 Tendons attach muscle to bone

Skeletal Muscle
Sarcomere:
- Causes contraction
- Made up of actin and myosin
Units of Muscle Fibers
1.
Origin: attached to the less
movable part of bone – proximal
attachment
2.
Insertion: attached to the more
movable part of the bone – distal
attachment
3.
Body: middle part of the muscle
3 parts of Skeletal muscle
 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
Fill in movement Definitions

Lines organs

Makes up walls of blood vessels

In the digestive system

Smooth – has no 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: contraction/shortening of
muscle with no movement
Tetanic: continued contraction of
muscle
Fibrillation; uncoordinated contraction
of muscle fiber
Convulsion; groups of muscles
contract in abnormal manner
Spasms: involuntary contractions