“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.
• Responsible for all body
movement.
• Responsible for body form
and shape (posture)
• Responsible for body heat
and maintaining body
temperature.
• Skeletal
• Smooth
• Cardiac
• Sphincter
•
•
•
•
Attached to bone
Striated (striped) appearance
VOLUNTARY
Contract quickly, fatigue easily, can’t
maintain contraction for long period
of time
• Each skeletal muscle cell
contains many nuclei
• Muscle cells are known as
muscle fibers
• Cell membrane is call
sarcolemma
• Cytoplasm is called sarcoplasm
• Visceral (organ) muscle
• Found in walls of
digestive system, uterus
and blood vessels
• Cells small and spindleshaped
• INVOLUNTARY
• Controlled by
autonomic nervous
system
• Act slowly, do not tire
easily, can remain
contracted for long time
• Found only in
the heart
• Striated and
branched
• Involuntary
• Cells are fused
– when one
contracts, they
all contract
• special circular
muscles in
openings of
esophagus
and stomach,
stomach and
small
intestine,
anus, urethra
and mouth.
• CONTRACTIBILITY – the ability
of a muscle to reduce the
distance between the parts of
its contents or the space it
surrounds.
• EXCITEABILITY (IRRITABILITY) –
the ability to respond to certain
stimuli by producing impulses.
• EXTENSIBILITY – the ability to be
stretched.
• ELASTICITY – ability of muscle to
return to its original length
when relaxing.
• Location:
– frontalis-forehead
• Size:
– gluteus maximus
• Direction of fibers:
•
external abdominal oblique
• Number of origins:
– Biceps-two headed muscle in humerus
• Location of origin and Insertion:
sternocleidomastoid- origin in sternum
• Action flexor:
– flexor carpi ulnaris- flexes the wrist
• Extensor:
– extensor carpi ulnaris- extends the wrist
• Levator and Depressor:
– depressor anguli oris-depresses the corner
of the mouth, raises or lowers body parts
• Muscles 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 between the origin and
the insertion.
• Rule: A muscle’s insertion bone moves
toward its origin bone.
• Groups of muscles usually contract to
produce a single movement.
• Sarcolemma: muscle cell
membrane
• Synaptic Cleft: gap
between the axon and
the muscle cell.
• MOTOR UNIT – a motor neuron plus all the
muscle fibers it stimulates.
• NEUROMUSCULAR JUNCTION – the junction
between the motor neuron’s fiber which
transmits the impulse – and the muscle cell
membrane.
• ACETYLCHOLINE – chemical neurotransmitter,
diffuses across the synaptic cleft (carries
impulse across synaptic cleft)
• MUSCLE FATIGUE – caused by the
accumulation of lactic acid in the muscles.
• OXYGEN DEBT – after exercise, the amount
of oxygen needed by the muscle to change
lactic acid back to glucose.
• MUSCLE TONE - When muscles are slightly
contracted and ready to pull.
• Improves:
-Coordination of all muscles involved
-Respiratory and circulatory system to
supply needs of active muscular
system
-Elimination of excess fat
-Joint movement involved with that
muscle activity
• Strength (capacity to do work) is
increased with training
• Muscle size increase due to change
in the sarcoplasm (cytoplasm found
in the individual skeletal muscle
fibers) Not the increase in the
number of muscle fiber cells
• Tendons: non-elastic cords
that attach muscles to bones
• Bones are connected at joints
• Dome-shaped muscle
that separates the
abdominal and
thoracic cavities, aids
in breathing
• ATROPHY –
wasting away of
muscle due to lack
of use.
• If we fail to exercise
our muscles
weaken and
become flaccid ex.
Quadriplegics,
elderly on bedrest,
extremity in a cast,
etc.
• Massage of these muscles is
essential in providing the
proper physiotherapy or a
general sense of comfort and
well-being to a patient, also
prevents atrophy in
debilitated patients
• HYPERTROPHY – an
increase in the size of
the muscle cell.
• when over exercise
the size of the muscle
fibers increase due to
a change in the
sarcoplasm (not due
to an increase in
number of muscle
fiber cells)
• STRAIN – tear in the muscle
resulting from excessive use.
Bleeding inside the muscle can
result in pain and swelling. Ice
packs will help stop bleeding
and reduce swelling.
– RICE : rest, ice, compression, elevation
• Rehabilitation: retaining of
injured or unused muscles
• MYALGIA – muscle pain
• TENDONITIS –
inflammation
of a tendon
• MUSCLE
SPASM
(cramp) –
sustained
contraction of
the muscle,
usually
because of
overuse.
• Or wry neck, may be
due to an inflammation
of the trapezius and/or
• Sternocleidomastoid
muscle
La belleza perece en la vida pero es
inmortal en el arte.
Leonardo Da Vinci