The Muscular System
Muscle System Functions
movement of body
blinking, and smiling
Allows you to hop,
skip, jump, or do
Causes heart beat
Sends blood to
different areas of
Provides movement of
Moves food through
Enables bladder control
Adjusts opening of pupils
Causes hair to stand on
end ( )
Is made up of Skeletal
Controlled by the
controlled Smooth Cardiac
Involuntary- not under
Types of Muscle Tissue
Comparison of Muscle Types
Muscle Type Skeletal Cardiac Smooth
Attached to Heart Walls of internal
Location bone organs + in skin
Movement of Beating of heart Movement of
Function bone internal organs
Control Mode Voluntary Involuntary Involuntary
Long + slender Branching Spindle shape
Striated- light Striated Non-striated
Characteristics and dark bands One or two One nucleus
Many nuclei nuclei (visceral)
of Muscles Masseter
Muscles External Obliques
Skeletal Latissimus dorsi
Muscles You Need to Know
2. biceps brachii 10
3. deltoid 15
4. external oblique 3
5. frontalis C
6. gastrocnemius 13
7. gluteus maximus 4
8. hamstring group
9. latissimus dorsi M7
11. pectoralis major E
12. quadriceps group
13. rectus abdominis
14. tibialis anterior J
16. triceps brachii
Location of Muscles
Muscle Tissue Anatomy
bundle of muscle
fibers – fascicle
Muscles are made up of bundles
of muscle fibers, called fascicles
Fascicle is a bundle of muscle
u T fibers
A muscle fiber is a muscle
s I A cell….made up of many
c s n Myofibrils
contain filaments Muscle
l s a Two types of
e u t Fascicle
m Muscle Fibers
Contain two types of Molecule
Z disc- point of
anchor of actin Thick Filaments
functional unit of a
between Z discs,
What parts do you
(bundle of fibers)
3. Muscle fiber
Muscle Tissue Anatomy Continued
What parts do you remember?....continued
F Muscle cell
I G F
Mechanics of a Muscle
What stimulates a muscle to
Your nervous system
What cells are involved?
Muscle cells and a motor neuron
Motor neuron sends
impulse to muscle cells
One neuron will form
synapses with many
What is this called?
A motor unit
Let’s take a look under
A the microscope.…
Mechanics of a Muscle
Where does stimulation occur?
How do motor neurons
impulse signal across the gap
What happens when a
muscle cell is stimulated?
Calcium ions are released into the muscle cell
Mechanics of a Muscle
What do calcium ions do?
Cause interaction between actin and myosin
How do actin and myosin interact?
Actin filaments slide over the myosin filaments
What model explains this?
Sliding Filament Model
Mechanics of a Muscle
What causes actin to slide
The head of myosin
connects to actin and
What is this connection
The binding of the myosin
heads throughout the
some myosin heads are
binding while other heads are
releasing the actin filaments.
This process must be
performed repeatedly during
a single muscle contraction
so that the muscle is able to
generate a smooth force
Mechanics of a Muscle
What provides the energy to swivel the head of
How exactly does the sliding filament model work?
In the sliding filament model of muscle contraction, the
(thin) actin filaments
[red] (that are attached
to the Z-line) slide (are
actually pulled) inward
along the (thick)
[blue], and the
from one Z line to the
next) is shortened.
Mechanics of a Muscle
When each sarcomere becomes shorter it
causes each myofibril to become shorter.
shorter it causes
the muscle fibers
to become shorter
overall muscle Sarcomere
Control of a Muscle
How long does a muscle cell
Until the release of acetylcholine
How strongly does a muscle fiber contract?
To it’s fullest extent.
So what controls the
strength of a contraction?
Number of muscle cells recruited
To get a stronger contraction, more
cells are stimulated
A single cell can’t contract harder
A Closer Look at Muscle Contraction
muscle to bone
of muscle to
bone (anchors muscle) Belly of
to bone that moves
when muscle contracts
_____- bulging middle
part of the muscle
Muscles originate on a _____bone in our body,
cross over a ______, and insert onto a ______
It is important to understand that all muscles
move from the ________ point
going toward the __________
It is because of the placement
of the muscles that we can
attach _________ to bone
don’t stretch when the force of
the muscle acts on them
When muscle contracts,
it pulls on the _______
Individual muscles can
only ____ in ____ direction
Muscles work in
______- Muscle that bends the joint when
Extensor Muscle that straightens the joint
is short, firm, tight
and thicker around.
Relaxed muscle is
stretched, long, loose
and thinner around.
When the biceps in the arm contracts the triceps
________ causing ________ of the arm.
When the triceps in the arm _________ the biceps
relaxes causing straightening of the arm.
______ of muscles are
needed because the
only active movement
of a muscle is to
contract to lengthen it
must be _________ by
the action of an
Warning: This illusion
The muscles, bones, and ligaments work
together to control body feel
can make youmotion. very
dizzy, especially if you
are prone to motion
Muscles In Action
HYPERMUSCLE: MUSCLES IN ACTION
Click above to get to this multimedia interactive HTML
document which will help you learn the muscle actions
of the human body.
Muscle + Bone Interaction
Let’s review the structures involved in
movement at a joint.
E Body (Belly)
B Contracted muscle
F Relaxed muscle
A sprain is a wrenching, twisting or stretching
injury to a ligament.
Sprains often affect the
ankles, knees, or wrists.
Result in pain, swelling, redness, bruising, and
difficulty using injured joint.
A strain is an injury to a muscle or
tendon, and is often caused by
overuse, force, or stretching.
difficulty using or
injured area in a
There are three degrees of muscle ruptures
A muscle tear may be partial or complete and
caused either by a direct blow or by overexertion.
A first-degree strain involves less than 5 percent
of the muscle.
Mild tears referred to as pulled muscles.
A second-degree tear is a greater rupture that
stops short of a complete tear.
There may be a defect of the muscle - a bump or an
indentation - at the site of the most pain.
You should be able to partially contract the muscle,
but not without pain
A third-degree rupture is a complete tear across
the width of the muscle
You will be unable to contract the muscle.
This is what happens when someone suddenly
drops while sprinting.
Muscle Pull Muscle Tear
Muscle pull- very slight tear
Chronic tear- gradual onset of pain
Acute tear- sudden dramatic pain
Shin splints is pain
resulting from damage to
the muscles along the shin.
Pain is felt in different areas,
depending on which muscles
Shin splints represent an
"overuse injury" and occur
most commonly in runners.
Treatment for Muscle Injuries
Rest: Stop all activities which
Ice: Helps reduce swelling.
Never ice more than 10-15 min.
at a time. Protect the skin.
Compression: Wrap the strained
area to reduce swelling.
Elevation: Keep the strained area as
close to the level of the heart as is
conveniently possible to keep blood
from pooling in the injured area.
Muscle spasm- when A muscle (or even a few
fibers of a muscle) involuntarily contract
Muscle cramp- involuntarily + forcibly
contracted muscle that does not relax
A forceful + sustained spasm
Nick named charley horse
Muscle feels tied up in knots
Can last anywhere from a few
seconds to a quarter of an hour
Caused by strain or injury
Tetanus is a preventable disease through vaccination
Caused by bacteria that enters the body
through the skin
Found in soil, dust and manure
Toxin bacteria produces interferes with nerve
transmission to your muscles and causes
them to seize up in painful spasms.
Tetanus typically starts in the jaw and muscles
of the face, quickly spreading to the arms and legs.
Intestines often seize up
Bladder fails to empty
Produced naturally by the body to support such functions as
fighting stress and promoting growth and development
Referred to as roids, juice, hype, weight trainers, gym candy,
arnolds, stackers, or pumpers
People use steroid pills, gels, creams, or injections to improve their
sports performance or the way they look.
Anabolic steroids cause many different types of problems
types of problems
premature balding or hair loss
nausea and vomiting
high blood pressure
shortening of final adult height
increased risk of heart disease,
stroke, and some cancers
Cerebral palsy is a group of disorders that affect a
person's ability to move and to maintain balance and
The disorders appear in the
first few years of life, and
usually don’t get worse over time.
People with cerebral palsy
may have difficulty walking. They may also
have trouble with tasks such as writing or
Some people with cerebral palsy have other
medical conditions, including seizure
disorders or mental impairment.
Cerebral palsy happens when the areas of
the brain that control movement and posture
do not develop correctly or get damaged.
Muscular Dystrophy- most well known of
A genetic condition that describes over 20
genetic and hereditary muscle diseases.
Characterized by progressive skeletal muscle
weakness, defects in muscle proteins, and the
death of muscle cells and tissue.
In some cases, cardiac and smooth muscles
Progressive Muscular Wasting (weakness)
Poor Balance and Frequent Falls
Walking Difficulty + Waddling Gait
Limited Range of Movement
Scoliosis (curvature of the spine)
Inability to Walk
Muscle Atrophy and Drooping Eyelids
Myasthenia gravis- chronic autoimmune
neuromuscular disease characterized by
varying degrees of weakness of the skeletal
Caused by a defect in the transmission of
nerve impulses at the neuromuscular junction
Antibodies (produced by the body's own
immune system) block, alter, or destroy the
receptors for acetylcholine at the
neuromuscular junction which prevents the
muscle contraction from occurring.
The characteristic symptom of myasthenia gravis is fatigability, which
means that a muscle that is used repeatedly starts to become weak.
The symptoms usually start in the face and spread to the other parts of
the body as the disease progresses.
Certain muscles such as those that control eye and eyelid movement,
facial expression, chewing, talking, and swallowing are often involved
The muscles that control breathing and neck and limb movements may
also be affected.
Patients initially complain of drooping eye lids that get worst as the day
goes on; they develop double vision, difficulty talking, and difficulty
Muscle weakness increases during periods of activity and improves
after periods of rest.
Poliomyelitis, often called polio is an acute
viral infectious disease which is spread from
person-to-person via the fecal-oral route.
The majority of polio infections are asymptomatic.
In about 1% of cases the virus enters the (CNS) via the
Within the CNS, poliovirus infects and
Old Polio The destruction of
& weakness weakness and
Atrophic right leg flaccid paralysis
(arrow) in patient Vaccination created
with paralytic polio 70 by Jonas Salk in
years in past 1955 has eliminated
dissection video link
A. Phalanges F. Ulna
B. Manus (hand) G. Radius
C. Alula (thumb) H. "Elbow“
D. Metacarpals I. Humerus
E. Carpal joint (wrist) J. "Shoulder" joint