Table of Contents
is the muscles are the contractile tissue of the body and their primary role is to contract and produce force and cause some kind of motion or spasm.
Some of them are necessary for the survival such as heart muscle, which contracts involuntary or continuous movements of the bowels called peristalsis!
In general, there are three types of muscles in our bodies:
- Smooth muscles - They are located in internal organs and blood vessels mostly. They cannot get tired and their contraction is very slow. They belong to the group of muscles called involuntary muscles
- Skeletal muscles - They are under influence of our will and we can control their contraction. They are connected to the bone with tendons and mostly control our skeletal movement. Unlike smooth muscles, these muscles can get tired.
- Heart muscle - A special kind of muscle, which cannot be identified with previous two types. It does not get tired and its contractions are involuntary!
Like any other tissue in our organism, muscles are made of cells, but special kind of cells called muscle fibers. The muscle cell is filled with special kind of structures called myofibrils. Myofibrils are divided into sarcomeres, which are made of actin and myosin and thanks to them the contraction is possible.
There are approximately 650 skeletal muscles in the human body which together account for about 40 % of a human's weight and of course, they are divided into certain groups.
Human muscle groups, by their localization are:
- Head & Neck Muscles
- Upper Extremity Muscles
- Back Muscles
- Thoracic Muscles
- Abdomen Muscles
- Pelvic Muscles
- Lower Extremity Muscles
They can also be divided by size - vastus, maximus, longus, minimus and brevis; shape - deltoid, rhomboid, wide, teres, trapezius or action – abductor, adductor, flexor, extensor, and elevator.