Muscular System
Muscles are tissues whose cells or muscle fibers have the function of allowing contraction and production of movements.
Muscle fibers, in turn, are controlled by the nervous system, which is responsible for receiving information and responding to it by carrying out the requested action.
Functions of the Muscular System
The Muscular System has some functions that are fundamental to the human body. See below what these functions are:
- Body stability;
- Production of movements;
- Body warming (maintaining body temperature);
- Body filling (support);
- Helps with blood flow.
Muscle Groups
Thehuman bodyis made up of approximately600 muscles, which work together with bones, joints and tendons to allow us to make different movements.
They are grouped as follows: muscles of the head and neck, muscles of the chest and abdomen, muscles of the upper limbs, and muscles of the lower limbs.
Learn about each of these groups below.
Muscles of the Head and Neck
The head and neck muscle group is made up of more than30 small musclesthat help express feelings, move the jaw or hold the head up.
See the table below to see how some of the main muscles in this group work:
| Muscle | Action |
|---|---|
| Front | Chew or bite. |
| Masseter | They move their jaws. |
| Sternocleidomastoid | Allows the head to turn or tilt forward and backward. |
Muscles of the Chest and Abdomen
The muscles in the chest and abdomen group allow breathing, prevent the body from bending and giving in to its own weight, among other movements.
The table below shows some of the muscles in this group and how they act in our body:
| Muscle | Action |
|---|---|
| Pectoral and Deltoid | Lift weights. |
| Intercostals | They work together with the diaphragm to carry air into the lungs. |
| Oblique | Tilt your chest forward. |
Muscles of the Upper Limbs
The muscles of the upper limbs are capable of applying precise pressure and allow flexibility and precision for delicate tasks or those that require a lot of strength.
Some examples of these muscles and their respective actions are described in the table below:
| Muscle | Action |
|---|---|
| Biceps | It is connected to the scapula and radius bones, and when it contracts it causes the arm to bend. |
| Opponent of the thumb | Allows movement of the thumb, as it uses muscles in the forearm and hand |
| Short adductor | Outward movement of the thumb. |
Muscles of the Lower Limbs
The muscles in the lower limbs are the strongest in the body. Thanks to the leg muscles, we can stand upright and maintain balance.
See the table below for some muscles in this group:
| Muscle | Action |
|---|---|
| Tailor (or sartorius) | It is the longest muscle in the body, when contracted it bends the leg and rotates the hip. It is the seamstress’ muscle, hence the name. |
| Dorsal flexors | They make your toes lift. |
| Achilles tendon | It is the strongest tendon in the body, inserted into the calcaneus bone. |
| Soleus, plantaris and gastrocnemius | They are plantar flexor muscles responsible for the movement of ballerinas standing on their toes. |
Types of Muscles
Muscles have different sizes, shapes and functions, which is why they are classified into three types: smooth, striated cardiac and striated skeletal.
Find out more details about each of them below.
Smooth or Non-striated Muscle
Smooth muscles are those that have involuntary contraction.
They are located in the hollow structures of the body, i.e. stomach, bladder, uterus, intestine, as well as the skin and blood vessels.
Its function ensures the movement of internal organs.
Striated Cardiac Muscle
They are muscles of involuntary contraction and are present in the heart (myocardium).
These muscles ensure the vigorous heartbeat.
Striated Skeletal Muscle
They are voluntary contraction muscles, that is, the movements are controlled by the human being’s will.
They are connected to bones and cartilage and, through contractions, allow movements, body positions, as well as stabilizing the body’s joints.