Transcript The Muscular System

Bodies in Motion
THE MUSCULAR SYSTEM
Functions of the Muscular System
 Motion
 Posture (tone)
 Respiration
 Production of body heat
 Communication by expressions and body language
 Constriction of organs and blood vessels
 Heartbeat (pulse)
Properties of muscle tissue
 Contractility: Ability to shorten with force.
Muscles can only pull, not push.
Excitability: The ability of a muscle to
respond to a stimulus, usually a nerve
signal
Extensibility: Muscle fiber can
stretch beyond its normal length
and still contract
Elasticity: A muscle can
return to its original shape
after being stretched
3 Types of Muscles
 Skeletal
 Smooth
 Cardiac
Skeletal Muscle:`
 Cells are called fibers
 Long, parallel cylinders with striations and
multiple nuclei
 Voluntary
 Also control reflexes
 Move the body
Gross Anatomy of Skeletal Muscle:
Chapter 9
 Muscles can only pull – never push
 Muscles must work in pairs to move body
parts
 The pairs are called agonists and antagonists
The
biceps
Is the
agonist
The triceps
is the
antagonist
Origin and insertion:
 The origin is the fixed (immobile) end of the
muscle
 The insertion is the movable end of the
muscle
Muscles are named for…
 Location: posterior/anterior, brachial (arm),
pectoral (chest), etc…. (Tibialis anterior)
 Number of heads: bi (2), tri (3), etc….
 Size: maximus, minimus, longus, major,
minor, etc…. (Peroneus longus)
 Origin / Insertion: The sternocleidomastoid
originates on the sternum and inserts on the
mastoid
Muscles you should know:
Origin, insertion, and action
 Orbicularis oculi (234)
 Orbicularis oris (234)
 Zygomaticus (major/minor) (234)
 Temporalis (237)
 Massester (237)
 Sternocleidomastoid (240)
 Trapezius (240)
… More Muscles …
 Latissimus dorsi (248)
 Pectoralis major (248)
 Biceps brachii (251)
 Triceps brachii (251)
 Gluteus maximus (256)
 Sartorius (258)
 Biceps femoris (258)