The human nervous system: parts, functions and diseases

Nervous system structure

What is the meaning of the nervous system?

The nervous system is a complex system that plays a role in regulating and coordinating all body activities. This system allows you to perform a variety of activities, such as walking, talking, swallowing, breathing, as well as all mental activities, including thinking, learning and remembering. It also helps you control how your body reacts in an emergency.

The nervous system in humans consists of the brain, spinal cord, sensory organs (eyes, ears, and other organs), and all the nerves that connect these organs to the rest of the body. This system works by taking information through certain body parts or senses, processing that information, and triggering reactions, such as making your muscles move, feel pain, or breathe.

In carrying out its work, the nervous system is divided into two structures or structures, namely the central nervous system and the peripheral nervous system. The central nervous system is made up of the brain and spinal cord, while the peripheral nerves are made up of nerves that connect the central nerves to the rest of your body. The peripheral nerves are divided into two major structures, namely somatic and autonomic nerves.

Anatomy and parts of the nervous system

Broadly speaking, there are three parts to the human central nervous system. The three parts are:

1. Brain

The brain is the main controlling engine of all bodily functions. As mentioned above, this organ is part of the human central nervous system. If the central nerve is the body's control center, then the brain is the headquarters.

The brain is divided into several parts with their respective functions. In general, the brain consists of the cerebellum, cerebellum, brain stem, and other parts of the brain. These areas are protected by the skull and brain membranes (meninges) and surrounded by cerebrospinal fluid to prevent brain injury.

2. Spinal cord

Similar to the brain, the spinal cord is also part of the central nervous system. The spinal cord is directly connected to the brain via the brainstem and then flows along the vertebrae.

The spinal cord plays a role in everyday activities by sending signals from the brain to other parts of the body and ordering the muscles to move. In addition, the spinal cord also receives sensory input from the body, processes it, and sends this information to the brain.

3. Nerve cells or neurons

part that is no less important than the anatomy of the nervous system is the nerve cells themselves or called neurons. The function of nerve cells or neurons is to deliver nerve implants.

Based on their function, neurons are divided into three types, namely sensory neurons that carry messages to the central nerve, motor neurons that carry messages from the central nerve, and interneurons that deliver messages between sensory and motor neurons in the central nerve.

Each neuron or nerve cell consists of three basic parts or structures. The anatomy of these neurons, namely:

Cell body, which has a nucleus.
Dendrites, which are shaped like branches and function to receive citumulus and carry impulses to the cell body.
Axons, which are parts of nerve cells that carry impulses out of the cell body. The axons are generally surrounded by myelin, which is a dense, fatty layer that protects the nerves and helps messages pass through. In peripheral nerves, this myelin is produced by Schwann cells.

These nerve cells can be found throughout the body and communicate with each other to produce responses and physical actions. Reporting from the National Institutes of Health, it is estimated that there are about 100 billion neurons in the brain. These nerve cells include 12 pairs of cranial nerves, 31 pairs of spinal nerves, and elsewhere.

Nervous system function

In general, the nervous system in humans has several functions. These functions are:

Gather information from inside and outside the body (sensory function).
Transmits information to the brain and spinal cord.
Processing information in the brain and spinal cord (integration function).
Transmits information to muscles, glands, and organs so that they can respond appropriately (motor function).

Each of the nervous system structures, namely the central and peripheral nerves, performs a different function. Here is the explanation.

Central nerve system

The central nervous system, which consists of the brain and spinal cord, has a function to receive information or stimuli from all parts of the body, then control and control that information to produce a body response.

This information or stimulation includes those related to movement, such as talking or walking, or involuntary movements, such as blinking and breathing. It also includes other forms of information, such as human thoughts, perceptions and emotions.

Peripheral nervous system

Broadly speaking, the function of the peripheral nerves is to connect the central nervous system response to organs and other parts of your body. These nerves extend from the central nerve to the outer areas of the body as a pathway for receiving and sending stimuli to and from the brain.

Each peripheral nervous system, namely somatic and autonomic, has a different function. The following is an explanation of the functions of the parts of the peripheral nervous system:

Somatic nervous system

The somatic nervous system works by controlling everything you are aware of and consciously influencing the body's response, such as moving your arms, legs, and other parts of your body. These nerve functions convey sensory information from the skin, sense organs, or muscles to the central nervous system. In addition, somatic nerves also carry a response out of the brain to produce a response in the form of movement.

For example, when you touch a hot flask, the sensory nerves carry information to the brain that this is a sensation of heat. After that, the motor nerves carry information from the brain to the hand to immediately avoid it by moving, releasing, or pulling the hand from the hot flask. This whole process takes place in approximately one second.

Autonomic nervous system

In contrast, the autonomic nervous system controls the activities you do unconsciously or without needing to think about it. This system is continuously active to regulate various activities, such as breathing, heart rate, and the body's metabolic processes.

There are two parts to this nerve:

1. The sympathetic system

This system regulates the resistance response from within the body when there is a threat to you. This system also prepares the body to expend energy and face potential threats in the environment.

For example, when you are anxious or afraid, the sympathetic nerves will trigger a response by speeding up the heart rate, increasing the respiratory rate, increasing blood flow to the muscles, activating the sweat-producing glands, and dilating the pupils of the eyes. This can make the body respond quickly in an emergency situation.

2. The parasympathetic system

This system is used to maintain normal body functions after something threatens you. After the threat has passed, this system will slow down the heart rate, slow down breathing, reduce blood flow to the muscles, and constrict pupils. This allows us to return the body to its normal state.

Nervous system disease

Various diseases or nervous disorders

There are several disorders or diseases that may occur to interfere with the vital function of the nervous system in humans. The following are the types of neurological diseases:

Alzheimer's

Alzheimer's disease is a disease that attacks brain cells and neurotransmitters (chemicals that carry messages between brain cells). This disease affects brain function, affects your memory and the way you behave.

Parkinson's

Parkinson's disease is a disorder that occurs when nerve cells do not produce enough dopamine, a chemical that is essential for smooth muscle control and movement.

Multiple sclerosis

Multiple sclerosis is a chronic disease that affects the central nerves. This condition is characterized by damage to the protective sheath (myelin) that surrounds the nerve fibers in the brain and spinal cord.

Bell's palsy

Bell's palsy is a sudden weakness or paralysis on one side of the face. This is because the nerves in your face become inflamed. Usually this condition is temporary and can heal within a certain period of time.

Epilepsy

Epilepsy is a condition characterized by recurring or recurring seizures. This condition can occur due to disruption of electrical activity in the brain.

Meningitis

Meningitis is an infectious disease that causes the membranes around the brain and spinal cord (meninges) to become inflamed. This disease is usually caused by a virus or bacteria.

Encephalitis

Encephalitis is an infectious disease characterized by inflammation of the brain tissue. Just like meningitis, this disease is also caused by a viral infection.

Brain tumor

A brain tumor is a lump of abnormal cells that grows in the brain. These lumps can be benign, but they can be malignant or cancer of the brain. This condition can damage your brain and cannot carry out its normal functions.

Injury to the brain and spine

brain injury is a brain-related injury that affects a person physically, emotionally, and attitudes. There are two forms of injury that may occur, namely traumatic and nontraumatic injuries. Stroke is a form of nontraumatic injury that may occur.

Similar to brain injury, spinal cord injury is damage to the spinal cord that causes loss of function, feeling, and mobility. This injury is most often caused by trauma.

Characteristics or symptoms of neurological disease

Nerve damage from certain disorders or diseases causes scars or lesions in your nervous system. This means that your neurons are no longer able to properly send signals throughout your body. This condition can cause various symptoms or characteristics, namely: