Muscular System
Now let's give our bone bag some muscles!
The muscles connect the bones together so we can Move!
They give you strength, without muscles, you can not move or act!
There are three types of muscles: skeletal muscles, smooth muscles and Muscle Cardiac.
Meet the Muscle
The muscular fiber
If you look at a cut of a muscle, it looks like a phone cable.
Each muscle fiber is composed of myofibrils, which in turn are composed of filaments of two proteins called actin and myosin.
It is the transverse movement of myosis along the actin that causes the shortening of the muscle fibers, and consequently the muscular contraction!
Come on, we're moving!
Muscles transform energy into motion.
They can be shortened by contracting or lying down when they are stretched...
In reality they do not lengthen, but they relax and thus take their maximum amplitude, without going beyond, thus avoiding the tear!
In the great majority, the muscles work in pairs, one pulling on one side and the other on the opposite side!
The biceps and triceps at the arm provide a good example, when the biceps contracts, the arm rises while the triceps is completely relaxed.
Conversely, when the triceps is contracted, the arm is lowered while the biceps relax completely!
Skeletal muscles
The muscles that attach to the skeleton are voluntary.
They act when you decide a thing like running or painting a landscape!
They control all movements of joints.
Skeletal muscles are made of fibers.
Smooth muscles
Smooth muscles, or involuntary muscles,do their work without "being told".
They control digestion and other functions without you thinking about it.
They are made of short cells that contract slowly and gently.
They can remain contracted for a long time, which is necessary when your stomach digests a big meal!
These involuntary muscles that you do not need to tie up to digest or to make your heart beat!
The latter do their job without our consciousinvolvement!
The brain "interact" in both cases, either to trigger the movement or to participate in its control!
The Heart muscle
The heart is a large hollow muscle on the inside.
It is made of powerful cells.
The heart is the only muscle of the bodythat functions at every moment of your life.
This involuntary muscle beats, it contracts about 70 times per minute without you telling it.
That makes almost 3 billion beats in 80years!
This is the most important of your muscles!
Imagine that you open and close your fist 70times a minute, 24 hours a day, all your life!
Get the Connection
Two types of fibers connect bones and muscles to each other: tendons, and ligaments.
Although both are very strong "fabrics", each has its own function!
The tendons
A Tendon is a kind of string that ends the muscle and attaches it to the bone.
When the muscle contracts, it shrinks and moves the bone.
Each muscle has one or more tendons at its ends.
Formed of collagen fibers, it is usually very resistant.
But it can also be victim of trauma, mainly during sports activities: tendinitis, which is an inflammation of the tendon,
Tendinosis, which is a non-inflammatory lesion or rupture, such as Achilles tendon rupture, tendon that connects the calf to the back of the foot.
The Ligaments
A ligament is a solid band of tissue that attaches two neighboring bones.
The ligaments can not stretch.
Consisting mainly of long molecules of collagen.
It is an extremely strong and flexible structure at the same time!
