MUSCLE= latin ‘musculus’=little mouse
Are you strong enough?
Skeletal muscle makes up about 40% of the
mass of the average human body. Muscles
are the engine that propels the body. They
turn energy into motion and efficient at
turning fuel into motion.
They are long lasting, self healing and grow
stronger with practice.
Main function is to:
Muscles are made of elastic fibers. These
fibers are like a rubber band that lengthens
and shortens. The thick and thin filaments
do the actual work of a muscle.
A muscle contraction occurs when these fibers
generate tension through the action of actin
and myosin cross-bridging.
This process describes the sliding of myosin
and actin filaments over each other.
Thick filaments are made of protein called
Thin filaments are made of another protein
Muscles cannot push- they can only pull.
Even when you push against a wall, each
muscle in your body is working by pulling.
When the muscles relax they stop pulling and
your arm and another muscle straightens it.
There are over 600 muscles that make up the
muscular fibers that are held together by
Properties or characteristics of muscles Excitability- ability to respond to a nerve
Contractibility- muscle fibers that are
stimulated by nerves- they contract or
become short and thick
Extensibility- ability to be stretched
Elasticity- allows the muscle to return to
its original shape after it has contracted
Main types of muscles:
2. visceral-smooth muscles
3. skeletal- striated
Can be described as voluntary and involuntary
CardiacThese muscles form the walls of the heart
Contract to circulate blood
Involuntary- function without us thinking
Cardiac muscle is involuntary striated
muscle. huge number of mitochondria per
cell to make energy.
visceral or smooth Found in the internal organs of the body such
as the digestive system, respiratory system,
blood vessels and the eyes
These contract to cause movement in these
Involuntary function without conscious
Smooth muscle is found in your airway,
digestive system, blood vessels and in
females the uterus.
Smooth muscle can stretch and maintain
tension for long periods of time.
It contracts involuntarily without you
thinking about it.
Skeletal or striated Attach to bones
Cause body movement
Voluntary- person has control over their
How muscles attach to bone:
1.Tendons- strong tough connective tissue
2. fascia- tough sheet-like membrane that
hold muscles together,covers and protects
3. Origin and insertion- when muscle
attaches to bone one section becomes the
origin (which does not move) and one end
is the insertion (the end that moves when
the muscle contracts)
Actions of the muscles:
Adduction- moving a body part toward the
Abduction- moving a body part away from
Flexion- decreasing the angle between 2
bones or bending a body part
Extension- increasing the angle between 2
bones or straightening a body part
Actions or movement continued:
Rotation- turning a body part around it’s
own axis- like turning the head side to side
Circumduction- moving in a circle at a joint
moving one end of a body part in a circle
while the other end stays stationary- like
swinging the arm in a circle
Seed question- which joints circumduct and
which joints rotate?
Supination- a rotation of the arm or foot in
which the hand can face up and foot tipped
to the outer edge
Pronation- when hand faces down and the foot
flattens out so that the arch strikes the
Major muscles of the body:
Refer to page 127 in the book:
Fill in worksheet on the major muscles of the
Terms related to muscle:
Hypertrophy of the muscle- increased muscle
Atrophy- decreased muscle mass
Contracture- muscle shortening
Fasciculation- involuntary muscle movement
ROM- range of motion- ability to move the
muscle and joint through a full rotation/
extension/flexion smoothly, and without pain
Active isotonic- patient is able to move area
by themselves without assistance
Active-assistive- patient can do some, but
will need some help, or can assist self
Passive- patient can not do activity
Static- isometric- patient can tense muscle
without moving joint
Resistive- strength building
fibromyalgia is a chronic condition
characterized by widespread pain in your
muscles, ligaments and tendons, as well as
fatigue and multiple tender points — places
on your body where slight pressure causes
Muscular dystrophy- this is an inherited
disease that leads to chronic muscle atrophy.
It appears in early childhood and most types
result in severe disability and early death
due to fat tissue replacing the muscle fibers
effecting cardiac muscle.
There is no cure, but physical therapy can
slow the progression
Signs and symptoms of MD vary according
to the type of muscular dystrophy. In
general, muscular dystrophy symptoms
Apparent lack of coordination
Progressive crippling, resulting in fixations
(contractures) of the muscles around your
joints and loss of mobility
Myasthenia gravis- a chronic condition where
nerve impulses are not properly transmitted
through the muscle. This leads to weakness
and paralysis. Any effort gives extreme
If the condition affects the respiratory
muscles it can lead to respiratory failure and
Myasthenia gravis cont.Symptoms are:
Difficulty talking, swallowing, choking
Drooping head and eyes
Muscle function better after rest
Difficulty lifting objects
Rhabdomyosarcoma- tumor of the muscle
tissue. This is rare, but prognosis is usually
poor. It metastasizes early and leads to
advanced malignancy quickly.
Muscle spasm- can occur in the legs and feet
due to overexertion, low electrolyte levels or
Strain- is an overstretching or injury to a
muscle and or tendon. Prolonged or sudden
muscle exertion is usually the cause.
Usually symptoms are edema, limited
movement and pain.
Treatment is rest, muscle relaxant, pain
medication, elevate the extremity and
alternate hot and cold applications.
think on this
where is your smallest muscle?
what is the longest muscle?
Are small and not striated
They are made up of thick and thin filaments
They have intermediate filaments that cross
like fish-net stockings
Intermediate filaments slide across thin
filaments and draw the muscle up in all