Download the muscular system

UNIT F
THE
MUSCULAR
SYSTEM
The Power system!
Nearly half our weight comes
from muscle tissue.
There are 650 different
muscles in the human body.
Muscles give us form and shape.
Muscles produce most of our
body heat.
3 main functions
Responsible for all body movement
Responsible for body form and
shape (posture)
Maintain body temp. and
producing heat
Types of muscle
SKELETAL
TYPES OF MUSCLES
SMOOTH
CARDIAC
SKELETAL MUSCLE
Attached to bone
Striated (striped) appearance
VOLUNTARY!!!!!
SKELETAL MUSCLE cont.
Multinucleated muscle
cell bundles
Muscle cell =muscle fiber
Sarcolemma = cell
Contract quickly,
membrane
fatigue easily, can’t
contract for a long
time
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Types of Muscles
• Skeletal muscle.
• Attached to bone.
• Striated (striped) appearance.
• Voluntary.
• Multinucleated muscle cell bundles (muscle cells
= muscle fibers).
• Sarcolemma = cell membrane.
• Contract quickly, fatigue easily, can’t maintain
contraction or long period of time.
SMOOTH MUSCLE
Only one nucleus
Unattached to bones
They do not tire easily and
contract for long periods
Involuntary
Smooth cont.
Found in walls of digestive system,
uterus and blood vessels
Controlled by
autonomic
nervous system
Types of Muscles Cont.
• Smooth muscle.
• Visceral (organ) muscle.
• Found in walls of digestive system, uterus and
blood vessels.
• Cells small and spindle-shaped.
• Involuntary.
• Controlled by autonomic nervous system.
• Act slowly, do not tire easily, can remain
contracted for long time.
CARDIAC MUSCLE
Found ONLY in the HEART
Striated and branched
Involuntary
Cells are fused when 1
contracts they all do
Types of Muscle Cont.
• Cardiac
muscle.
Found only in the
heart.
Striated and
branched.
Involuntary.
Cells are fusedwhen one
contracts, they all
Sphincter
Special circular
muscles in
openings of
esophagus and
stomach,
stomach and
small intestine,
anus, urethra
and mouth.
Characteristics of Muscles
Contractibility = ability of a muscle
to reduce the distance between the
parts of its contents or space it
surrounds
Characteristics cont.
Excitability =
(irritability) the
ability to respond
to certain stimuli
by producing
impulses
Characteristics cont.
Extensibility – the
ability to be stretched
Elasticity – ability of
muscle to return to
its original length
when relaxing
Movement
Move bones by pulling on them
As a muscle contracts it pulls
the insertion bone closer to
the origin bone. Movement
occurs at the joint
Go to video
RULE
A muscle’s insertion
bone moves toward
its origin bone
Movement cont.
Groups of
muscles contract
to produce a
single movement
Movement Cont.
Motor Unit –
a motor neuron plus all
the muscle fibers it
stimulates
Movement cont.
Neuromuscular Junction –
the junction between the
motor neuron’s fiber which
transmits the impulse
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Movement cont.
Acetylcholine –
chemical
neurotransmitter,
diffuses across
the synaptic cleft
( carries the
impulse across
synaptic cleft.)
Movement cont.
Muscle Fatigue –
Caused by the
accumulation of lactic acid
in the muscles
Muscle cont.
Oxygen Debt -
After exercise the amount of
oxygen needed by the muscle to
change lactic acid back to glucose
Muscle cont.
Muscle Tone Muscles are
slightly
contracted and
ready to pull
Muscle cont.
Diaphragm -
Dome shaped
muscle that
separates the
abdominal and
thoracic cavities and
aids in breathing.
The muscles
DISORDERS
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Atrophy
• Wasting away of muscle due to lack
of use.
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Hypertrophy
• an increase in
the size of the
muscle cell
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Strain vs. Sprains
• Strain- affect
muscles or
tendons
• also called
pulled muscle
• muscle
becomes
overstreched
and tears
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Sprains
• affect ligaments
• usually from trauma
• you overstretch ligament or tear
ligament
• PAINFUL
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Muscle Spasm
• Cramp
• sustaind contraction of muscle
• due to overuse
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Myalgia
• Muscle Pain
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Tendonitis
• Inflammation of a tendon
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Muscular Dystrophy
• Gentic
disorder
• weaking
muscles
• Different
degrees
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THE END
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