The Muscular System

by **OrjoWan** Tue Jan 25, 2011 12:31 am

The Muscular System

One of the most amazing things about the human body
is the incredible range of movement and mobility it has.
This day to day activity is accomplished by our muscles through
the extraordinary and facinating ability of converting chemical energy,
energy stored in nutrients, into mechanical energy,
energy of movement.
Muscles are often viewd as the "machines" of the body.
They help move food from one organ to another,
and carry out our physical movement.

There are three diffrent kinds of muscles in our body:
cardiac, smooth, skeletal.

What's Below
Muscle Types
Cardiac
Smooth
Skeletal
Muscluar System
Muscle-Bone Interactons
Flexors
Extendors
Abductors
Adductors
Tendons and Ligaments
Major Skeletal muscles
Facial
Neck
Shoulder
Arm
Forearm
Thorax
Abdomen
Hip
Pelvis/Thigh
Leg
Muscle Types
Cardiac

Cardiac muscles are involuntary and found only in the heart.
They are controlled by the lower section
of the brain called the medulla oblungata,
which controlls involuntary action throughout your body.
Think about how horrible it would be to have
to consciously tell your heart to beat,
with the consequence of forgetting being death.
What about when you went to sleep!?!
But luckily enough,
the medulla oblungata does all that for us.

Your heart cells come in long strips,
each containing a single nucleus,
one of the key factors in determining which
of the three classes any particular muscle is.
Located at the walls of the heart,
its main function is to propel blood into circulation.
Contraction of the cardiac tissue is caused
by an impuse sent from the medulla oblungata
to the SA nerve located at the right atrium

Smooth

Your smooth muscles,
like your cardiovascular muscles, are involuntary.
They make up your internal organs,
such as your stomach-hyper link, throat-hyper link,
small intestine-hyper link,
and all the others, except your heart.

Unlike cardiovascular muscles,
smooth muscles are generally spherical,
as most other human cells are,
and each contains one nucleus.

Skeletal

The skeletal muscles are the only voluntary muscles of your body,
and make up what we call the muscular system.
They are all the muscles that move you bones
and show external movement.

Unlike either of the other two classes,
skeletal muscles contain multiple nuclei because of its large size,
being in strips up to a couple of feet long.

Muscular System

The muscles we have in our body are
divided into three classes of muscles:
cardiac, smooth, and skeletal.
Usually, when we think of muscular system we often
only remember the skeletal muscles because they make up
what is recognized as the muscular system.
The muscular system, composed of over 600 muscles,
come in a variety of shapes and forms.

Diffrences between each muscle are recognized by location,
function, structure, and the way they are contracted.

Muscle-Bone interactions

LEVER SYSTEM

A lever is a rigid bar on which a given load
is moved with supporting help from a fulcrum.
A fulcrum is a fixedpoint on which lever can move
in diffrent ways or angles.
The whole muscular system interacts in this kind
of way with the skeletal system-hyperlink.
Given a load the muscles pull the bone up or
in any direction againsrt the load.

Your joints-hyperlink usualy seem to be the fulcrum
on which you move the lever or bone.
For example, try lifting a book with your hand
and puting your elbow on the table.
You can move the book in any direction with the help
of the joints in your elbow,
and the book is lifted in any direction
due to the muscles contractions.

Skeletal muscles can be broken down
into groups based upon the type of movement they portray.
The movement of the muscle is based upon the type
of joint (hyperlink-Skeletal system) upon which the muscle works.
Skeletal muscles can't expand,
or make themselves longer, but they can contract,
or make themselves shorter, so they generally work in pairs.
One contracts, and in doing so stretches the other,
and reverses its effects on the joint.

For example, when you contract your major arm muscle,
which is called the bicep,
in return the lower arm muscle, called the tricep, extends.
So as you contract one muscle the other one extends.

These effects can be broken down into groups of their own:
flexors, extensors, adductors, and abductors.
Flexors and extensors become plantarflexors and dorsiflexors,
respectively, when located within either the wrist or ankle joints.

Flexors

Flexors bend at the joint, decreasing the interior angle of the joint
The «bracius» humorous, or bicep, is a flexor of the elbow joint,
bringing the fist towards the shoulder.
If a flexor appears in either the wrist or ankle joints,
it becomes a plantarflexor

Extendors

Opposites of flexors, extensors unbend at the joint,
increasing the interior angle
«graphic here, possibly the same as that above».
The «tracius» humorous, or tricep,
is an extensor of the elbow joint,
taking the fist farther away from the shoulder.
If an extensor is found in the wrist or ankle joints,
it becomes a dorsiflexor

Abductors

Abductors take away from the body,
like lifting the arm to the side.
Abd- means to take away, like abduct and abdicate.
Spreading out your fingers uses abductors,
because you are taking away your fingers from an imaginary
line running down your arm

Adductors

Adductors, the opposites of abductors, move toward the body.
Add- means to increase or include.
By lowing an arm raised to the side,
or moving your fingers together while keeping them straight,
your muscles are adducting.

Tendons and Ligaments

As fascinating as they are, muscles alone can't do the job.
At every joint, tendons and ligaments also help out.
Muscles wouldn't be very useful alone because
they don't directly connect to the bone,
so even if they contract, they wouldn't be moving anything.
Instead, muscles are connected to tendons,
when themselves are connected to the bones.
When the muscles contract,
they pull on the tendons, which in turn pull on the muscles,
and that causes movement.

But without ligaments,
that movement wouldn't be too useful because
it would not be directed movement.
Without ligaments, instead of bones bending
or rotating about each other when muscles contract,
they would slide by each other.
Ligaments are what hold the bones together.
They connect at the ends of muscles
and keep them from slipping and sliding,
and force them to bend.

Major Skeletal Muscles

The muscual body is divide into ten diffren areas where muscles can be found:
facial, neck, shoulder, arm, forearm, thorax, abdomen, hip, pelvis/thigh, leg.

Facial

In the facial are one finds all the muscles wich move the face.
Orbicularis oculi-sound are the two muscles that move the eye are.
Frontalis-sound and Temporalis-sound are the two
muscles which move the forehead and sides of your head.
Zygomaticus-sound ands Masseter-sound
are the two muscle that work in conjunction
to move tyoou jaw and upper lip area.
Orbicularis oris-sound is the muscle which moves your lips.

Neck

The neck area is almost entirely moved
by the sternohyoid-sound and Sternocleidomastoid-sound.
These muscles allowthe neck to move your head left and right.
They work with the platysma muscle to control
how far you can move your head left and right.
What allows your head to move up and down
is the trapezius-sound.
The trapezius is so large that it extend down
to the shoulder and thorax area.
The trapezius is a good example of how some muscles
are named by their shape.
the trapezius looks just like a trapezoid.

Shoulder

A group of muscles all work together
to move the whole shoulder area.
This group takes into account the trapezius-sound,
deltoid-sound, infraspinatus-sound, teres major-sound,
and the rhomboid major-sound.
The rhomboid major is called so because its shaped
like the geometric shape of a rhombus.
Along with the help of the ball and
socket joint-hyperlink in your shouder,
these gruop of muscles allow your arm to throw a softball,
pick things over your head,
and give your arms a good strech early in the morning.

Arm

Most known amongst teenage weight lifters is the arm area.
The famous bicep brachii-sound is the muscle that allows
you to bring your forearm close to your body and form
a huge ball of muscle wich catches
a lot of attention amongst weight lifters.
The tricep brachii-sound and brachialis-sound
are the two other muscles located in the arm region.
These muscles allow a person to do push-ups!

Forearm

A majority of the muscle in the forearm
help control a part of the arm.
Amongst these is the Berachiodialis major-sound,
palmaris longus-sound, and Flexor carpi radialis-sound.
The name of the flexor carpi radialis is a good example
of how muscles are named by their function and location.
This muscle is named carpi because
of the bones that it helps move, the carples.
Also, the name of radialis is made by the bone that
its attached to, the radius

Thorax

The thorax is the set of muscles which carrying your head,
arms, stomach, and any other upper body areas.
These muscles are the trapezius-sound
and latissimus dorsi-sound.
Usually, the majority of the muscles of the thorax can be
damaged easly is one dose not streach before excersice,
or lifts a heave load.

Abdomen

The abdominal area consists of the muscles that allows
you to bend down and move your waist from side to side.
The interanl oblique-sound and external oblique-sound
are the muscles that move your body from left to right.
The Transversus abdominus-sound and
Rectus abdominus-sound, along with the trapezius-sound
an latissimus dorsi-sound allow you to bend down and grab objects.

Hip

Only two muscles make up the hip area.
These are the gluteus medius-sound and gluteus maximus-sound.
Probably the laziest muscles in the whole system
the gluteus set of muscles are used only to sit down on.

Pelvis/Thigh

An overlaping of muscles is what makes this area so firm.
The pelvis area is usualy refered to as the upper part of the leg.
Muscles like the pectineus-sound and illiopsoas-sound ,
which help support the upper leg area are known
as pelvic muscles.
Thigh muscles are very rich in capillaries and support the whole body.
The upper thigh muscles are abductor longus-sound,
Gracilis-sound, Sartorius-sound, and Tensor fasciae latea.
The lower thigh muscles are rectus femoris-sound,
vastus lateralis-sound and medialis-sound.
Located in the back of your leg are the hamstrings-sound.
These muscles help you run, jump, and walk!

Leg

Helping the thigh region support the body is the Leg region.
These muscles like the Gastrocnemius-sound,
soleus-sound, porenius longus-sound,
and Tibialis anterior-sound absorb
the impact when one walks and runs.
they also give beter cordination for moving.
the thigh region trust the body forward while
the leg region coordinates where it should be thrusted
and where it should stand.