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MUSCULAR SYSTEM
Almost all movement results from muscle
contraction.
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Running a marathon
Beating of the heart
FUNCTIONS OF MUSCLE
Allows movement
Produce heat
Keep body erect and maintains posture
Protection of internal organs
2 Types of Muscle Movement
1. Voluntary- muscles that can be made
to contract by a person’s desire to move.
2. Involuntary- muscles which contract
automatically. Ex. Heartbeat, digestion
Voluntary muscle
Involuntary Muscle
TYPES OF MUSCLE TISSUE
Smooth--involuntary, found in internal
organs. AKA visceral muscle
Striated--voluntary, attached to the
skeletal system.
Cardiac--involuntary, makes up the heart
Striated Muscle (attached to the
skeleton)
STRIATED (SKELETAL)
MUSCLES NAMED
ACCORDING TO:
Direction of muscle fibers
Ex. Sternocleidomastoid
Location
Originates at the sternum and
Size
clavicle and connects to the
mastoid bone
Number of origins
Shape
Origin and insertion
Action
TERMS RELATING TO
MUSCLE
Tendons- strong cords of tissue which
connect muscle to bone
Sphincter muscles- special circular
muscles that control an opening. Found in
the walls of the anus, urethra and
intestines.
Myoglobin-a red pigment found in muscle
fiber. It is a protein that provides O2. It is
similar to hemoglobin that is found in RBC.
HOW DO MUSCLES MOVE?
Muscles move bones by pulling on them.
Most muscles extend from one bone to
another and cross at least one joint.
Contraction of the muscle causes body
movement by pulling one of the bones
toward the other across the joint.
POINTS OF ATTACHMENT
ORIGIN--also called the head of the
muscle. Attaches to the more stationary
bone. (doesn’t move)
INSERTION--attaches to the more
movable bone. This is the part that moves
when the muscle contracts.
Some muscles will have multiple origins, ie
biceps brachii and triceps brachii
Muscles tend to function together to
accomplish specific movements.
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example: deltoid, biceps brachii, and
pectoralis major all help to flex the arm.
many muscles are members of more than one
group, depending on the type of movement.
WHAT MAKES A MUSCLE
MOVE??
Muscle cells are stimulated by a nervous
impulse that enters the muscle fiber
through a motor neuron.
Point of contact between a nerve ending
and muscle fiber is a neuromuscular
junction.
When muscles are stimulated repeatedly
without rest, the contraction strength will
decrease resulting in fatigue.
When O2 supplies run low, muscle cells
produce lactic acid. Higher lactic acid
levels are what makes muscles sore after
exercise.
MUSCULAR DISORDERS
Muscular Dystrophy--inherited, chronic
disease. Unknown cause. Muscles
degenerate and become weak. Muscles
atrophy.
Myasthenia Gravis--chronic, progressive
disease results from destruction of
receptors at the neuromuscular junction.
Muscular weakness leads to paralysis.
Defect in immune system.
MUSCULAR DYSTROPHY
WHAS CRUSADE FOR CHILDREN
Mattie Stepanik – Oprah Show
http://www.youtube.com/watch?v=YTqIIoVwvN0
Muscle Atrophy
muscle shrinkage due to disuse.
muscle will lose tone, this leads to flaccid
muscle.
caused by:
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poliomyelitis
paralysis
prolonged bedrest
immobilization-cast
MUSCLE ATROPHY
Muscle hypertrophy
muscles increase in size because of
increased use-such as exercise.
cardiomegaly
other disorders
Fallen arches (flatfeet)-weakening of leg
muscles that support the arch.
Hernia-weak place in the muscular
abdominal wall. the intestines bulge
through an opening in the wall.
Tetanus (lockjaw)-infectious disease.
Continous series of spasms of voluntary
muscles. Puncture wound is entry.
Spores of the bacteria C. tetani live in the soil and are
found around the world. In the spore form, C. tetani may
remain inactive in the soil, but it can remain infectious for
more than 40 years.
Infection begins when the spores enter the body through
an injury or wound. The spores release bacteria that
spread and make a poison called tetanospasmin. This
poison blocks nerve signals from the spinal cord to the
muscles, causing severe muscle spasms. The spasms
can be so powerful that they tear the muscles or cause
fractures of the spine.
The time between infection and the first sign of
symptoms is typically 7 to 21 days. Most cases of
tetanus in the United States occur in those who have not
been properly vaccinated against the disease.
Inguinal Hernia
Fallen Arches (Flat-feet)
Myalgia-muscle pain
Myopathy-any muscle disease
Charley horse-tearing of muscle. Trauma
induced. Severe, prolonged pain.
Fibromyalgia syndrome -chronic
disorder. Widespread aching pain, tender
points and fatigue. Unknown cause.
Common Tender Points of
Fibromyalgia
Nocturnal myoclonus -jerking of the
limbs that may occur normally when a
person is falling asleep.