Nervous System

It is made up of a set of organs in the human body that have thefunction of capturing messages, stimuli from the environment, “interpreting” them and “archiving” them.

Consequently, hedevelops responses, which can be given in the form of movements, sensations or observations.

Nerves that make up the nervous system

The Nervous System is divided intotwo fundamental parts:central nervous systemandperipheral nervous system.

Central Nervous System

The Central Nervous System is made up of thebrainandspinal cord, both surrounded and protected by three membranes calledmeninges.

Brain

Thebrain, which weighs approximately 1.5 kilos, is located in the cranial cavity and hasthree main organs: the cerebrum, the cerebellum and the brain stem;

It is the most important organ of the nervous system. Considered the largest organ, as it occupies the largest part of the brain, the brain is divided into two symmetrical parts: theright hemisphereand theleft hemisphere.

Thus, the outermost layer of the brain, full of recesses, is calledthe cerebral cortex, which is responsible for thought, vision, hearing, touch, taste, speech, writing, etc.

Furthermore, it is the seat of conscious and unconscious acts, memory, reasoning, intelligence and imagination, and also controls the voluntary movements of the body.

Cerebellum

Located at the back and below the brain, the cerebellumcoordinates the precise movements of the body, as well as maintaining balance. In addition, it regulates muscle tone, that is, it regulates the degree of contraction of the muscles at rest.

Brainstem

Located at the bottom of the brain, the brain stem conducts nerve impulses from the brain to the spinal cord and vice versa.

In addition, it produces nervous stimuli that control vital activities such asrespiratory movements, heartbeats and reflexessuch as coughing, sneezing and swallowing.

Spinal Cord

Thespinal cordis a cord of nerve tissue located within thespinal column. At the top it is connected to thebrain stem.

Its function is to conduct nerve impulses from the rest of the body to the brain and coordinate involuntary acts (reflexes).

Peripheral Nervous System

The peripheral nervous system is made upof nervesthat originate in the brain and spinal cord.

Its function is to connect the central nervous system to the rest of the body. It is important to note that there are two types of nerves: cranial and spinal.

• Cranial Nerves: distributed in 12 pairs that leave the brain, and their function is to transmit sensory or motor messages, especially to the head and neck areas.
• Spinal Nerves: There are 31 pairs of nerves that leave the spinal cord. They are made up of sensory neurons, which receive stimuli from the environment; and motor neurons that carry impulses from the central nervous system to the muscles or glands.

According to itsaction, the peripheral nervous system can be divided intothe somatic nervous systemandthe autonomic nervous system.

• Somatic Nervous System: regulates voluntary actions, that is, those that are under the control of our will, as well as regulating the skeletal muscles of the entire body.
• Autonomic Nervous System: acts in an integrated manner with the central nervous system and has two subdivisions: the sympathetic nervous system, which stimulates the functioning of the organs, and the parasympathetic nervous system, which inhibits their functioning.

In general, these two systems haveopposite functions. While thesympathetic nervous systemdilates the pupil and increases the heart rate, theparasympathetic nervoussystem, in turn, constricts the pupil and decreases the heart rate.

Ultimately, the function of theautonomic nervous systemis to regulate organic functions, so that the internal conditions of the organism remain constant.