MUSCLES
1
FUNCTIONS OF MUSCULAR
SYSTEM

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Body movement
Maintain posture
Respiration
Produce body heat
Communication
Constriction of organs and blood vessels
Heartbeat
2
Connective Tissue Sheaths in
Skeletal Muscle
3
Figure 10.1a
Connective Tissue Sheaths


The MUSCLE FASCIA is loose fibrous connective tissue on
the outside of the muscle. It creates a slippery surface for
muscles to rub against each other. Deep to the fascia is the
EPIMYSIUM, (dense irregular fibrous connective tissue),
and which eventually becomes the tendon (which is
connected to bone). The epimycium extends into the muscle
belly to form compartments called FASICLES. This tissue
surrounding the fascicles is now called the PERIMYCIUM.
Each fascicle contains MUSCLE FIBERS, which are
individual muscle cells, each one surrounded by
ENDOMYCIUM. When you eat steak and find it’s stringy,
each string is a fascicle, and the fat around the whole outside 4
of the slice of meat is near where the fascia is.
TYPES OF MUSCLE PATTERNS

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PARALLEL
PENNATE
CONVERGENT
CIRCULAR
5
PARALLEL MUSCLE
The fascicles are parallel.
They are long fibers, which
can contract to 75% of their
length. They contract a long
way, but they are relatively
weak, because there are
relatively few fascicles. E.g.
Sternocleidomastoid.
6
Arrangement
of Fascicles in
Muscles
7
Figure 11.3
PENNATE
PENNATE (means “feather shape”) MUSCLES: three types:



UNIPENNATE; looks like half a feather. The fascicles are
short, but there are more of them. They are stronger, but do
not have the same length contraction ability of the parallel
muscles.
BIPENNATE are fascicles that insert into the tendon from
both sides; they are stronger than unipennate.
MULTIPENNATE are the strongest (biceps femoris). The
fascicles are in multiple bundles inserting on one tendon
8
PENNATE
9
10
CONVERGENT
CONVERGENT MUSCLE has more fibers
than parallel, but contracts a greater distance
than pinnate. E.g. Pectoralis major.
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12
CIRCULAR MUSCLE
CIRCULAR MUSCLE (Sphincter) is arranged
in a circle, with a small area of tendon on the
sides. It allows closure of the eyes, mouth,
etc. They are not very strong, but they don’t
need to be.
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14
TERMS:

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
ORIGIN = The region which usually doesn’t move when the
muscle contracts. Look at the biceps brachii; does the
shoulder move when I bend my arm? No; the shoulder =
origin.
INSERTION= The point of attachment that moves; bend
arm, radial tuberosity = attachment.
AGONIST = The main muscle for a particular action; bend
arm, biceps = agonist.
ANTAGONIST = Does the opposite action; bend elbow,
antagonist extends. Every muscle in the body has to have an
antagonist.
SYNERGIST = The muscle that helps the agonist. There are
several muscles that assist when the arm is bent.
15
Muscle Attachments
16
Muscle Types

Skeletal: elongated
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Smooth: spindle shaped
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striated
Voluntary
Moves the skeleton
no striations
Involuntary
Found in organs and lining of blood vessels
Cardiac: cylindrical shaped


striated
17
involuntary (only responds to direct electrical stimulation)
SKELETAL MUSCLE


Theses are very long fibers (biceps muscle
can be 8-10 cm).
They have thousands of nuclei because they
start from many stem cells that fuse together
into one skeletal muscle fiber.
18
Skeletal Muscle


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Myoblasts exist in adults, so muscle heals
well.
A muscle cell torn in half can regenerate.
There are almost no muscle diseases for this
reason (muscular dystrophy is the main
muscle disease).
19
Skeletal Muscle: Longitudinal section
In skeletal
muscle
fibers, there
are light and
dark stripes
called
striations,
which can be
seen under a
microscope.
20
Skeletal Muscle ON CROSS
SECTION
21
A cross section of skeletal muscle
looks like bundles of circles
because you are looking at cut
fascicles.
22
Skeletal Muscle

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The plasma membrane of muscles is called a
SARCOLEMMA.
The cytoplasm of muscle cells is called
SARCOPLASM.
Muscle cells contain many mitochondria and
other organelles.
One type of unusual organelle found only in
muscle cells is called a myofibril. They are
packed in bundles and fill up most of the cell.
23
•
MUSCLE MYOFIBRILS
• Cylindrical organelles found within muscle cells
• Contain actin and myosin myofilaments
• Extend from one end of the muscle fiber (muscle cell) to the other
• Contain sarcomeres joined end to end.
24
Skeletal Muscle: Longitudinal
section
These striations
(stripes) are caused
by dark and light
bands.
The dark band is
called an A band.
(There is an “A” in
dark)
The light band is
called an I band.
There is an “I” in
light)
25
This is all part of one muscle cell that has many nuclei.
26
Every
dark band + light
band is one
sarcomere
In the center of each light I band is a Z disc
One sarcomere is the area from one Z disc to the next Z disc.
So, each sarcomere extends from the middle of one light band to the
middle of the next light band. In the center of the dark band is a lighter 27
colored area called the H zone. It is the area of the myosin without heads.
SARCOMERES



The striations result from the internal structure of SARCOMERES
within the sarcoplasm.
The sarcomere is the basic structural and functional unit of
skeletal muscle. The sarcomere is what contracts.
Each sarcomere

Extends from one Z disc to the next Z disc

Has a light colored H zone in the center (found in the middle of
the dark band, which is in the center of the sarcomere. It is the
area of myosin in the center that does not have myosin heads).

Contains parts of two I (light) bands and all of one A (dark) band

Contains overlapping actin and myosin myofilaments.
28
Note: the I band consists only of actin myofilaments.
The A band consists of both actin and myosin.
29
30
Actin and Myosin

Sarcomere model video
Sarcomeres consist of two types of myofilaments
made out of protein:

thin (ACTIN) myofilaments



Look like two strands of beads twisted together.
Actin myofilaments are attached to the Z disc at one end.
thick (MYOSIN) myofilaments.


Both ends of a thick filament are studded with knobs
called myosin heads (look like little golf clubs).
Myosin is NOT attached to the Z disc.
31
32
Actin
Myosin
Actin
Myosin
33
Don’t confuse these terms!
MUSCLE FASCICLE: a group of muscle fibers,
surrounded by perimysium.
MUSCLE FIBER: a single muscle cell
MYOFIBRIL: a long organelle inside a muscle fiber,
contains actin and myosin myofilaments.
MYOFILAMENTS: these are proteins, and there are two
types: actin (with troponin and tropomyosin) and myosin.
The myofilament is the lowest level of organization that is
composed of actin, myosin, troponin, and tropomyosin
proteins.
Therefore, a myofilament is part of a myofibril, which is
inside a muscle fiber, which is inside a muscle fascicle.
34
MECHANISM OF CONTRACTION



The Sliding Filament Theory
Contraction results as the myosin heads of the thick filaments
attach like hooks to the thin actin filaments at both ends of the
sarcomere and pull the thin filaments toward the center of the
sarcomere.
The myosin head is like a hook with a hinge. After a myosin
head pivots at its hinge, it draws the actin closer, then lets go,
springs up again to grab the actin filament again, pulls it closer,
and it keeps repeating this until the entire actin filament has
been drawn in as far as it can go.
The sites where the myosin heads hook onto the actin are called
cross-bridges.
35
36
Sarcomere Contraction
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The complete process of contraction of the sarcomere takes
only a fraction of a second.
The actin and myosin filaments do not shorten; they
merely slide past each other.
The energy required is ATP.
The A band (dark stripe) in a sarcomere does not
change length in a contraction.
This sliding filament mechanism begins whenever calcium
ions bind to the thin filament.
Where does the calcium come from?
37
SARCOPLASMIC RETICULUM AND
T TUBULES


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Within the cytoplasm of all body cells is an
endoplasmic reticulum.
The endoplasmic reticulum in muscle cells is
called the SACROPLASMIC RETICULUM.
It surrounds each sarcomere like the sleeve of a
loosely crocheted sweater.
38
Sarcoplasmic
reticulum is in
blue
T tubules are in
yellow
39
Calcium is needed
for muscle contraction

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The sarcoplasmic reticulum stores a lot of calcium
ions, which are released when the muscle is stimulated
to contract.
The calcium diffuses through the sarcoplasmic
reticulum to the actin filaments, where they trigger the
sliding filament mechanism of contraction.
After the contraction, the calcium ions are pumped
back into the sarcoplasmic reticulum for storage.
40
Calcium is needed for muscle
contraction



ACTIVE TRANSPORT is required to return the
calcium ions to the sarcoplasmic reticulum.
It also requires energy to break the cross-bridge so the
myosin head can cock back again, ready to spring onto
the next binding site.
Therefore, ATP is used.
 ATP is used to return calcium to the sarcoplasmic
reticulum
 ATP is used to cock back the myosin heads
41
ATP is required for contraction

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ATP attaches to the myosin myofilaments
 Provides energy for the movement of the cross
bridges
ATP is required for muscle relaxation
ATP releases part of its energy as heat.
 That is why we get hot when we exercise
 When we are cold, we shiver (muscle contraction)
to warm up.
In order for the mitochondria to produce enough ATP,
it needs oxygen and the sugars that are in storage.
42
For contraction to take place, you need a
nerve signal and calcium

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For skeletal muscle to contract, the synaptic knob of
a neuron must first release a chemical called
ACETYLCHOLINE onto the region where it sits
on the muscle cell, known as the ENDPLATE.
Calcium is also needed for muscle contraction.
The nerve signal is called an ACTION
POTENTIAL.
It causes a release of calcium from the sarcoplasmic
reticulum, which causes contraction.
43
Muscle Contraction



In a muscle fiber, an action potential results in
muscle contraction. How does this happen?
The action potential continues to travel along the
sarcolemma (cell membrane of the muscle).
Part of this electrical impulse breaks away from
the sarcolemma and travels down the T-tubules,
while the rest of the electrical impulse continues
longitudinally down the muscle cell to the next
sarcomere and T-tubule.
44
T tubules are in
yellow
45
T TUBULES


T TUBULES (“T” stands for “transverse”)
are continuations of the sarcolemma (cell
membrane) which invaginate to the deepest
regions of the muscle cell.
Since the T tubules conduct the nerve impulse
throughout the muscle cell, all the sarcomeres
of that cell contract at the same time.
46
Muscle Contraction

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The action potential of the nerve goes down the Ttubules and causes calcium to leak out of the
sarcoplasmic reticulum.
The calcium causes the muscle fibers to contract.
After a while, the calcium gets pumped back
where it came from, the muscle fibers relax,
although it requires gravity or another muscle to
pull the sarcomere back to its original length.
How does the calcium cause the muscle fibers to
contract?
47
TROPOMYOSIN is a single long protein strand like a
piece of yarn that winds around the actin filament.
 Tropomyosin blocks actin’s attachment site for the
myosin head, so the myosin “hook” has nothing to grab
onto, thus preventing contraction.
TROPONIN is a globular complex of three proteins, and
is found in clumps around the tropomyosin protein.
 Troponin is the specific molecule that provides the
calcium binding site on actin.
 Calcium binds to troponin and causes troponin to move
a little, taking the tropomyosin thread with it, so the
attachment sites on the actin molecule are now
exposed. The myosin heads can now hook into the
exposed sites on the actin myofilament.
Both troponin and tropomyosin cover the actin filament
when the muscle is relaxed.
48
This is an
illustration of
an actin
molecule.
You can see
the thready
tropomyosin
and the
globular
troponin
proteins
wrapping
around the
doublestranded
actin.
49
When
calcium binds
to the
globular
troponin, it
moves,
taking the
tropomyosin
thread with it.
This exposes
the myosin
binding site
on the actin.
50
Calcium in muscle contraction

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
When the muscle cell is stimulated to contract by an
action potential, calcium channels open in the
sarcoplasmic reticulum and release calcium into the
sarcoplasm.
Some of this calcium attaches to troponin, causing a
conformational change that moves tropomyosin out of the
way so that the myosin heads can attach to actin and
produce muscle contraction.
When the calcium gets pumped back where it came from,
the tropomyosin protein blocks the myosin head again so
it can no longer get its hook into the actin filament, and
the muscle will relax.
51
Rigor Mortis


A new ATP molecule must bind to the myosin
before the cross-bridge can be release. When ATP
is not available after a person dies, the crossbridges that have formed are not released, causing
muscle to become rigid (rigor mortis)
NOTE: Sarcomeres lengthen during muscle
relaxation, but only if gravity or an opposing
muscle pulls the sarcomere back to its original
length.
52
Muscle Contraction

http://www.youtube.com/watch?v=CepeYFvq
mk4

http://www.youtube.com/watch?v=InIha7bCT
jM&NR=1
53
Sequence of events
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The action potential reaches the cell membrane
The action potential reaches the T-tubules
The ion channels in the sarcoplasmic reticulum open
Calcium ions move along their concentration gradient
Actin forms cross-bridges to myosin
The actin myofilaments move closer to each other,
causing contraction of the sarcomere.
NOTE: A muscle fiber will not respond to a stimulus
until that stimulus reaches the threshold level.
54
Muscle Contraction
A muscle TWITCH is one single muscle fiber
contraction.
 It takes 1/20th of a second.
 How is it that I can pick up and hold a chair if the
fiber only contracts for 1/20th second?
 There are ten thousand fibers per muscle; each
one contracts at different intervals, so contraction
is maintained, just like tug-of-war. One person in
ten can drop the rope and get a better grip
because the others are maintaining the tension.
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Motor Units
A MOTOR UNIT is a single neuron and all of
the muscle fibers on which it synapses.
If one neuron sends a signal, only its muscle
fibers contract (the motor unit). This allows
for strength variations in lifting a chair vs. an
eraser. For full strength, all the motor units
contract. For half strength, half of the motor
units contract.
56
Motor
Units
There are 3 motor units in this diagram; that allows for 3
different levels of contraction. The more motor units there
are, the more precisely the muscle can respond.
57
Motor Units



The action potential continues from one motor neuron
to the next motor neuron until the last neuron lands on
its target cells; in this case, skeletal muscle fibers.
A single motor neuron and all the skeletal muscle
fibers it innervates constitute a motor unit.
A muscle in your tongue may only have a few muscle
fibers innervated by a neuron to allow for precise
movement. However, large thigh muscles may have as
many as 1000 muscle fibers per neuron, since
precision is not necessary.
58
Motor Units


The muscles of the back are larger motor units
(many muscle fibers per neuron). Since there
are fewer motor units present (one neuron for a
thousand muscle cells, we get strength, but less
precision.
The muscles that move the tongue have
smaller motor units (one neuron for 10 muscle
cells). Since there are many motor units
present = less strength, more precision.
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60
61
TETANUS TOXIN


A toxin caused by a certain bacteria can cause muscle to remain
contracted (in tetanus).
It quickly results in death because the diaphragm and other
respiratory muscles cannot function properly, and the person
suffocates.
The bacteria that make this toxin
live deep in the soil and cannot
survive in air.
If you step on something that
imbeds soil deeply into your
tissues (like a rusty nail), you
might contract the bacteria.
You will need a tetanus vaccine
before the toxins accumulate.
62
Muscle Tone



Even when muscles are relaxed, some of their fibers
are still contracting, giving the muscle some tone.
Therefore, the normal state of a muscle, with some
contraction, is called muscle tone. This is important
in posture so you can stand upright but mostly relaxed.
Muscle tone refers to the constant tension produced by
muscles of the body over long periods of time. It is
responsible for keeping the back and legs straight, the
head held in an upright position, and the abdomen
from bulging. it declines during REM sleep.
63
Motor Neurons
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
A neuron (nerve cell) that innervates (supplies)
skeletal muscle is called a motor neuron (causes the
body to move). There are 2 motor neurons involved
in this task.
The Upper Motor Neuron has its cell body in the
brain, and its axon (like a stem) lands on the cell
body of the Lower Motor Neuron, which is in the
spinal cord.
The axon of the Lower Motor Neuron leaves the
spinal cord and innervates the muscle.
64
Upper and Lower Motor Neurons
(in red)
Upper
motor
neuron
Lower motor
neuron
65
Muscle Tone


Hypertonia
 Can present clinically as either spasticity or rigidity. Seen
in upper motor neuron diseases, such as multiple
sclerosis or cerebral palsy.
Hypotonia
 Seen in lower motor neuron diseases (spinal cord
damage and ALS/Lou Gehrig Disease)
 Can present clinically as muscle flaccidity, where the
limbs appear floppy, stretch reflex responses are
decreased, and the limb’s resistance to passive movement
is also decreased.
66
Muscle Spasticity: Hypertonia



Clinically spasticity is defined as velocity dependent
resistance to stretch.
Passively moving (the doctor does the movement) the
patient’s elbow quickly will elicit spastic twitches, but
passively moving elbow slowly is normal.
It mostly occurs from upper motor neuron lesions (scar,
tumor, or other damage), but it can also present in multiple
sclerosis, which is an autoimmune condition. Can also be
seen in cerebral palsy (lack of oxygen at birth).
67
Muscle Spasticity


There is a difference in cause of two of the most
common spasticity conditions, spastic diplegia
(cerebral palsy) and multiple sclerosis.
In spastic diplegia, the upper motor neuron lesion
arises often as a result of neonatal asphyxia (lack of
oxygen in a newborn), while in conditions like
multiple sclerosis, spasticity is from multiple
sclerosis, which is an autoimmune destruction of
the myelin sheaths around nerve endings.
68
Muscle Spasticity

Causes include





Spastic diplegia (Cerebral palsy)
Multiple sclerosis
Spinal cord injury
Stroke
Test for clonus to see if spasticity is present.
69
Muscle Clonus



Clonus (from the Greek for "violent, confused motion") is a series
of involuntary muscular contractions initiated by a reflex.
Clonus is a sign of certain neurological conditions, and is
particularly associated with upper motor neuron lesions such as
in spastic diplegia, stroke, multiple sclerosis, spinal cord damage.
Clonus is most common in the ankles, where it is tested by
rapidly dorsiflexing the foot. If the foot then jerks 5 times or
more, clonus is present.
70
Muscle Rigidity


Unlike spasticity, rigidity is velocityindependent resistance to passive stretch.
There is uniform increased tone whether the
elbow is passively moved quickly or slowly.
71
Muscle Fasciculations


These are small, local, involuntary muscle
contraction and relaxation visible under the
skin arising from the spontaneous discharge
of a bundle of skeletal muscle fibers (muscle
fascicle).
Fasciculations have a variety of causes, the
majority of which are benign, but can also be
due to disease of the lower motor neurons.
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Muscle Fasciculations

Benign causes of fasciculations include:

Magnesium deficiency






Diarrhea
Overexertion
Inadequate intake from diet (almonds are a good
source of magnesium)
Dehydration
Fatigue
A small neuron dying can also cause
fasciculations.
73
Muscle Fasciculations

They can also be caused by long-term use of:






Benadryl (antihistamine)
Dramamine (for nausea and motion sickness).
Caffeine
Sudafed (for allergies)
Asthma medicines
ADD medicines
74
Muscle Fasciculations

More serious conditions causing
fasciculations include




Fibromyalgia
Myasthenia Gravis
Lyme Disease
Rabies
75
Hyperreflexia



We talked about hypertonia; some people have
hyperreflexia.
The most common cause of exaggerated reflexes is
spinal cord injuries (upper motor neuron diseases).
Other causes include
 Medication
 Stimulants
 Hyperthyroidism
 Electrolyte imbalance
 Severe brain trauma.
76
Hyporeflexia


This means diminished or absent reflexes.
The most common cause is lower motor
neuron diseases.
77
Muscle Contractures




Muscle contractures can occur from paralysis,
muscular atrophy (immobilization from a cast),
muscular dystrophy, and chronic spastic conditions
like cerebral palsy.
Fundamentally, the muscle and its tendons shorten,
resulting in reduced flexibility.
Muscle contractures in tendons are caused from the
fibrinogen leaking out of the fibroblasts, which turn
the elastic fibers into inelastic fibers.
Most treatments involve surgery, so physical therapy
efforts focus on prevention of contractures.
78
Sprint Runners

Why do sprint runners tire out during the last part of a
fast run?
Once the sprint-runner has used up the available
glucose, or has produced too much lactic acid, the
muscles fatigue.

http://www.youtube.com/watch?v=MTn1v5TGK_w

79
Oxygen Debt





Anaerobic respiration produces lactic acid, which
causes the painful cramps because it creates an oxygen
debt.
The amount of oxygen needed to replenish the
supply following aerobic demand is called the
oxygen debt.
When you continue to breathe heavily after exercising,
it means you have an oxygen debt.
Muscles can do without oxygen for a while pretty well,
unlike the brain.
To pay back a minor oxygen debt, you just have to
breathe heavily for a while.
80
EXERCISE

1.
2.
3.
4.
5.
There are many physiological benefits of
exercise:
Improved muscular strength, endurance,
flexibility
Improved cardio-respiratory endurance
Increased bone density and strength
Relief from depression
Increased HDLs
81
Hypertrophy




Weight training and other exercises can cause muscles to hypertrophy
(enlarge). This occurs as more myofilaments and myofibrils are produced
inside a myofiber (muscle cell), causing the muscle cellto enlarge. The
number of mitochondria also increases, causing additional enlargement.
However, you don’t grow new muscle cells. The number of cells in a
skeletal muscle remains relatively constant following birth. Myoblast stem
cells don’t grow into new muscle cells; they just patch up damaged cells.
Hypertrophy can happen in two ways:

Increase in number of myofibrils inside a muscle cell

Which causes the increase in size of individual muscle cells (myofibers)
Muscle hypertrophy is greater in males due to the hormone testosterone.
82
83
Hypertrophy




Eating protein does not automatically increase muscle. The
average person only needs one ounce of protein a day, two if
you work out.
One ounce is the size of a deck of playing cards.
Two ounces is like one mini hamburger.
Most people eat too much meat.
Fun Fact: -You use 200 muscles to take one step.
84
Fun Facts






A muscle cell is about as thin as a hair.
Muscles make up 1/3 of your body weight.
There are 655 muscles in the body…that is
three muscles per bone!
We all have the same number of muscle cells.
Muscles can generate 40 pounds per square
inch.
If all the muscles in the body were able to
contract at once, they could pull 25 tons!
85
Atrophy





Lack of use causes muscle ATROPHY. This happens quickly.
Astronauts can lose 40% of their muscle in two weeks! It is
regained quickly, too.
Atrophy is a decrease in muscle size because of the decrease in
myofilaments within muscle fiber.
Severe atrophy involves the permanent loss of skeletal muscle
fiber and the replacement of those fibers by connective tissue.
Damage to the nervous system, or a severed motor nerve can
cause atrophy. The muscle becomes flaccid (having no tone) .
Casting a broken limb also leads to temporary atrophy.
86
Muscular Dystrophy


This refers to a group of inherited muscle
disorders in which skeletal, cardiac, and smooth
muscle tissue degenerates and the person
experiences progressive weakness and other
symptoms, including heart problems.
The muscle is replacement by fat and other
connective tissue.
87
Muscular Dystrophy


MUSCULAR
DYSTROPHY
This is a genetic lack of a
protein called
DISTROPHIN. It causes
the muscle tissue to harden,
inhibiting contraction,
causing progressive
paralysis.
 Duchenne muscular
dystrophy is more
common in males.
88
Muscle Problems



Tendonitis is an inflammation of the tendon or
its attachment point. It usually occurs from
overuse of the muscle to which the tendon is
attached.
A strain is a tear in a muscle. Remember, a
sprain is a tear in a ligament.
A muscle strain will heal faster than a torn
ligament because muscles have good blood
supply and ligaments do not.
89
Treatment for Injuries: RICE


Rest
Ice



Compression



20 minutes on, 20 minutes off
Ice pack or frozen bag of peas!
Ace wrap from distal to proximal
Don’t leave any openings while wrapping
Elevation
90

Above the heart
Treatment for Injuries


Ice for the first 72 hours (NO heat!)
Anti-inflammatory medicines




Ibuprofin, 600 mg TID (3x a day)
Over the counter (OTC) pills are 200 mg
Heat and massage as needed after third day.
Can try a muscle stimulator too…works pretty
well!
91
Muscle Spasms



Muscle spasms/cramps are sudden and involuntary muscle
contractions. They are painful, spastic contractions that are
usually caused from overexertion. Lactic acid builds up and
irritates the overused muscles, causing inflammation. If the
muscle remains in spasm for longer than a few minutes, might
need heat and massage to increase circulation.
Avoid spasms by stretching before and after activities.
For people with frequent low back spasms throughout the day, a
portable muscle stimulator that clips to the belt will help a
great deal.
92
Muscle
stimulator to
relieve
muscle
spasms or to
prevent
muscle
atrophy in
casts
$59
http://www.m
edicalproduct
sonline.org/m
eprondi75mu.
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93
94
$3.50
http://www.m
edicalproduc
tsonline.org/r
ecaclel10pa.
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95
Fibromyalgia (muscle and tissue pain)





Common disorder in adults, especially women
Painful muscles, debilitating fatigue, sleep
disturbance, and joint stiffness
Many trigger points: painful lumps in muscles
Treatment includes anti-inflammatory
medicines, physical therapy, acupuncture, and
exercise.
Muscle stimulators help
96
Ganglion Cysts





Ganglion cysts arise as outpouchings from fluid filled
areas such as the fluid around tendon sheaths.
When the fluid, called synovial fluid, leaks out from these
spaces, it can become a cystic structure.
Treatment is to drain the fluid with a needle, but the fluid
can be jelly-like and difficult to remove, and they
frequently grow back.
If conservative treatments fail to correct the cyst, an
operation can be done to excise the cyst.
Then you do a surgery to scoop out the whole cyst, find
the stalk and tie it off.
97
• Ganglion cyst
98
Baker’s Cyst




A Baker's Cyst, or popliteal cyst, is a collection of
fluid in the back of the knee joint.
A Baker's cyst is usually a symptom of another
problem, or it may be an incidental finding with no
significant meaning.
Most often in adults the Baker's cyst is found in
conditions where there is chronic swelling or fluid
accumulation in the knee joint.
These conditions include knee arthritis, meniscus
injuries, and ligamentous injuries.
99
Baker’s Cyst

Treatment of a Baker's cyst that is the result of a
problem within the knee consists of treating the
underlying problem. These treatments may include
anti-inflammatory medications and cortisone
injections.
100
• Baker’s Cyst
101

Rotator Cuff Injury


http://video.about.com/orthopedics/Rotator-CuffInjury.htm
What is an MRI?

http://video.about.com/orthopedics/MRI.htm
102
AGING


With aging, fibrous connective tissue
replaces some muscle fibers, causing
decreased strength.
As people age, the number of muscle
fibers decreases, and new ones cannot be
added.
103
FUN FACTS ABOUT STRENGTH




The strongest humans can lift about 3 times their own body
weight, but the average gorilla can lift 10 times its own body
weight! Gorillas can lift 4,600 pounds.
But the strongest creature is the ant. If you had the strength of
an ant, you could lift over your head and carry 6,600 pounds.
The flea, however, can jump up to 200 times its own height.
This is equivalent to a man jumping the Empire State Building
in New York.
Elephants are the only animals that cannot jump!
104
105
Smooth and Cardiac
muscle
106
SMOOTH MUSCLE CELLS



These are found around internal organs
(intestines, uterus, blood vessels).
They are involuntary and not striated.
When smooth muscle contracts around the
intestines, the movement is called
PERISTALSIS.
107
SMOOTH MUSCLE CELLS
•
•
•
•
•
Smooth muscle cells are small and spindle shaped,
usually with one nucleus per cell.
They contain less actin and myosin, and the
microfilaments are not organized into sarcomeres.
As a result, smooth muscle cells are not striated.
They contract more slowly and do not develop an
oxygen debt.
Smooth muscle cells can spontaneously generate
action potentials that cause the cell to contract.
108
SMOOTH MUSCLE CELLS
•
•
•
•
Smooth muscle is not under voluntary control,
whereas skeletal muscle is voluntary.
Some hormones in the digestive system can
stimulate smooth muscles to contract.
They have specialized cell to cell contacts that
allow the action potential to spread to all of the
smooth muscle cells in a given tissue.
This allows them to function as a unit and
contract at the same time.
109
Characteristics of smooth muscle






There are no distinct sarcomeres
They contract more slowly than skeletal muscle…their twitch
time is very long = several seconds
It doesn’t get tired (“I’m too tired to urinate!”)
They contract in response to neurons as well as hormones and
changes in local environment (amount of oxygen, lactic acid,
etc).
They may be autorhythmic (self-exciting); they can contract
spontaneously without being stimulated (like cardiac muscle).
They do not develop oxygen debt.
110
111
Smooth Muscle
112
CARDIAC MUSCLE CELLS



Only found in the
heart.
The cells are
involuntary (like
smooth muscle) and
striated (like skeletal
muscle).
They have
intercalated discs
which join each cell.
113
Cardiac Muscle
114
Cardiac Muscle




Cardiac cells are long, striated, and branching,
with one nucleus per cell.
The actin and myosin myofilaments are
organized into sarcomeres, but not as uniformly
as in skeletal muscle.
As a result, cardiac muscle cells are striated, but
not as distinctly as skeletal muscle.
Cardiac muscle is involuntary and does not
fatigue.
115
Cardiac Muscle



Cardiac muscle cells are connected to one
another by intercalated discs which facilitate
action potential conduction between
themselves.
This allows them to function as a unit and they
all contract together.
Contraction of cardiac cells is influenced by
hormones, such as epinephrine.
116
Cardiac Muscle



As one cell contracts, the action potential goes
through all the cells, and they all contract as a
unit. That’s why the heart contracts all at once.
It has an intrinsic beat. The cells contract on
their own, without a signal.
Even if you chop a heart up, each piece will
beat by itself!
117
Summary
Skeletal
muscle
Smooth
muscle
Cardiac
muscle
Many
One
One
Involuntary
or
voluntary?
Voluntary
Involuntary
Involuntary
Striated
or
non-striated
Striated
Non-striated
Striated
Number of
nuclei
per cell
Where
is it
found?
Inserts
onto bones
Intestines,
blood vessels,
other organs
Myocardium
of heart
MUSCLE
Adductors
Biceps femoris
Brachialis
Deltoid
Gastrocnemius
Gluteus medius
Gracili
Infraspinatus
Internal Oblique
Latissimus dorsi
Pectoralis major
Pectoralis minor
Psoas major
Quadriceps femoris
Rectus abdominis
Semimembranosus
Semitendinosus
Serratus anterior
Supraspinatus
Tensor fascia latae
Teres major
Trapezius
Triceps brachii
BEEF CUT
Top (inside) round
Bottom (outside) round
Shoulder rose
Outside chuck (chuck)
Round heel
Top sirloin
Inside round cap
Top blade
Sirloin butt
Ribeye; Loin eye
Brisket
Brisket
Tenderloin; filet mignon
Knuckle; Sirloin tip
Flank
Top (inside) round
Eye of round
Boneless short ribs
Chuck tender
Tri-tip
Shoulder Tender
Outside chuck
Ranch Cut
Muscle Musician
• http://vimeo.com/47875656