The brain is the central part of the nervous system (formerly called the central nervous system – CNS), whose main function is to process and integrate information.
The human brain has an approximate mass of 1.4 kg and is protected by the cranial cavity. It consists of the brain, thalamus, hypothalamus, mesencephalon, bridge, cerebellum and spinal bulb (or medulla oblongata).
Structures of the Brain
The brain is divided into two hemispheres, left and right, connected to each other, being the most developed part of the brain, totaling almost 90% of the encephalic mass. It has as characteristic the surface formed by furrows that delimits regions called cerebral turns (convolutions).
Its outermost part is called the cerebral cortex , constituted by the cellular bodies of the neurons . Due to the visual aspect of this part, it is classified as gray matter.
The inner part of the brain, in the majority, is formed by the prolongations of the neuron and by its clearer appearance, when compared to the cortex, being classified as white matter.
Some deeper brain grooves divide the brain into distinct lobes , according to their specific functions:
- the frontal lobe , located in the anterior part, is responsible for motor control, through thought, speech and smell;
- the parietal lobe , located on the upper sides of the head, controls the sensations coming from the skin, muscles and tendons;
- the temporal lobe , located on the lower side of the head, controls hearing;
- the occipital lobe , located in the back of the head, controls the vision.
In addition to the motor functions related to movements and sensations, the cerebral cortex is related to intelligence, learning, memory, interpretation of sensations and the elaboration of physiological responses.
The thalamus and hypothalamus are located in the lower part of the brain. The thalamus is a region of integration between the electrical impulses coming from different regions, such as the cerebral cortex.
With the exception of the nerve impulses coming from the nose, all other information passes through the thalamus and is redirected to the different parts of the cerebral cortex. In addition, it is related to conscious control, alertness and attention.
The hypothalamus , located just below the thalamus ( hypo, inferior), is responsible for the balance and adjustment of various physiological functions:
- Participates in the control of body temperature, blood pressure, sensations, such as hunger and thirst, sexual impulses etc .;
- It is also responsible for participating in the integration of the nervous system with the endocrine system, producing hormones or controlling some glands.
The midbrain , located after the thalamus and hypothalamus, is a region that controls the degree of muscle contraction, called muscle tone, and body posture.
The bridge is made up of nerve fibers that integrate the cerebral cortex and the cerebellum. Its function is related to the control of movements of the eyes, neck and body in general. He also participates in the control of muscle tone, posture and body balance.
The cerebellum is located at the back of the brain, near the bridge. It has its nerve fibers attached to the cerebral cortex, the midbrain, the bridge, the bulb, and the spinal cord . Participates in the control of muscle tone, balance and body posture.
It coordinates muscle activity, so that voluntary movements, such as walking, running, playing instruments, swimming or simply maintaining balance, occur without the need for conscious control.
The spinal bulb (or medulla oblongata ) lies at the base of the encephalon, in contact with the spinal cord. It is related to involuntary functions, such as heart rate control, respiratory movements, etc.