Peripheral Nervous System: Functions and Parts

Do you know what the function of the peripheral nervous system is, what are the parts of the peripheral nervous system or why the central nervous system and the peripheral nervous system should work in coordination?Peripheral Nervous System

The peripheral nervous system is made up of a large number of nerves and is responsible for functions as diverse as breathing, voluntary movements or responses in dangerous situations. In addition, without the existence of this system, the brain could not receive information, preventing decision-making that favors survival. If you want to know more about this system, keep reading our online Psychology article: Peripheral nervous system: functions and parts.

Peripheral nervous system

The nervous system is the set of nerves and specialized cells, neurons, which is responsible for controlling all functions of the body, as well as relating and coordinating the actions of different organs and parts of the body.

Its activity is carried out through the emission and reception of electrical signals or nerve impulses. From the anatomical point of view, the nervous system is divided into the central and peripheral nervous systems. The central nervous system is composed of the brain and spinal cord.

Peripheral nervous system: definition

The peripheral nervous system (SNP) is the part of the nervous system that is made up of nerves and neurons that are outside the brain and spinal cord. This neural network of the SNP connects the brain and spinal cord with the rest of the body, allowing the exchange of information.

The peripheral nervous system is divided into the somatic and autonomous nervous system.

  • The somatic peripheral nervous system is responsible for sensory and motor information.
  • The autonomic peripheral nervous system: it is responsible for the control of involuntary bodily functions. The autonomic or vegetative peripheral nervous system, in turn, is divided into the sympathetic nervous system and parasympathetic nervous system.

functions of the Peripheral nervous system

What are the functions of the peripheral nervous system? Next, we explain the main functions of the peripheral nervous system:

  • The main function of the peripheral nervous system is that of connection and relationship between the brain and the spinal cord with the rest of the body: the organs, limbs, and skin.
  • It allows the brain and the medulla to send and receive information from the environment, which allows the reaction to external and environmental stimuli.
  • This system allows the activation of the muscles to perform both voluntary and involuntary movements.
  • The peripheral nervous system plays a basic role in ensuring the maintenance of stable internal conditions. It depends on the control of breathing, digestion, salivation, etc. It allows you to perform these functions without thinking consciously of them.
  • The escape or fight responses also depend on this system. Prepares and mobilizes the body to respond quickly to situations of danger or threat.
  • Thanks to it, information about the environment is transmitted to the brain, which is necessary to generate responses. These reactions have the function of protecting the organism and are vital for survival.
  • The nerves of the peripheral nervous system are not able to make complex decisions, but without their transmission of information to the brain, it could not elaborate responses.

Peripheral nervous system: parts

The main parts of the peripheral nervous system include the cranial nerves, spinal nerves, and nerve ganglia. How is the peripheral nervous system formed? The peripheral nervous system is made up of nerve ganglia and 43 pairs of nerves; 12 pairs of cranial nerves and 31 spinal pairs.

Cranial nerves

The cranial nerves are part of the peripheral nervous system. The 12 pairs of cranial nerves are located in part of the head and neck. Its functions are sensitive, motor or mixed:

  1. Olfactory Nerve (I): is responsible for stimuli and olfactory information.
  2. Optic Nerve (II): sends visual stimuli to the brain.
  3. The oculomotor nerve (III): intervenes in the muscular movements of the eye.
  4. Trochlear nerve (IV): controls one of the eye muscles that allow the movement of the eyeballs.
  5. Trigeminal Nerve (V): transmits sensory information about the face and mouth, as well as chewing.
  6. Abductor Nerve (VI): enables abduction, that is, the movement of the eye to the opposite side of the nose.
  7. Facial Nerve (VII): controls several muscles of the face, being able to create facial expressions, as well as receiving taste information from the tongue.
  8. Vestibulocochlear nerve (VIII): responsible for auditory impulses, balance, and orientation.
  9. The glossopharyngeal nerve (IX): This nerve is related to the reception of signals from the tongue and pharynx and the issuance of orders to this area.
  10. Vagus Nerve (X): conducts impulses from the pharynx and larynx to the brain, receives gustatory information from the epiglottis and influences the swallowing action.
  11. Accessory Nerve (XI): activates the thoracic, abdominal and back muscles.
  12. Hypoglossal Nerve (XII): transmits information to the muscles of the throat and tongue.

Spinal nerves

Spinal nerves arise from the spinal cord and drive stimuli from the rest of the body. These nerves have both a sensitive and motor part. The 31 pairs of spinal nerves and distribute as follows:

  • Eight pairs of cervical nerves (C1 to C8) that leave the cervical spine.
  • Twelve pairs of dorsal or thoracic nerves (T1 to T12) that emerge from the thoracic spine.
  • Five pairs of lumbar nerves (L1 to L5) leaving these from the lumbar area.
  • Five pairs of sacral nerves (S1 to S5) that arise from the sacral bone, located at the base of the spine.
  • A pair of coccygeal nerves in the coccyx.

Nerve ganglia

The nodes are a group of neuronal bodies that are part of the peripheral nervous system. They are interspersed in the path of the nerves and are divided into sensory or autonomous ganglia, in relation to the function they play.

Peripheral nervous system: diseases

The peripheral nervous system is not protected by bone structures, which makes it relatively vulnerable to a number of diseases. Conditions can be acquired or from birth. What are the most common diseases of the peripheral nervous system? The most common pathologies of this system are neuropathies, they refer to the damage or disease of one or several nerves.

There are several types of this disease, due to the number of nerves that form the SNP. Symptoms can develop rapidly or slowly, and develop in years. Symptomatology usually occurs on both sides of the body and begins with the fingers of the extremities. Neuropathy usually manifests itself through numbness, pain, burning, tingling, weakness, numbness, etc. Some of the most common types of neuropathies are the following:

  • Carpal tunnel syndrome: pressure on the wrist nerve, causing numbness and loss of movement in the palm of the hand and fingers. This syndrome is associated with people who work normally with their hands performing repetitive movements. Here you will find more information about the symptoms, causes, and treatment of carpal tunnel syndrome.
  • Compression of the ulnar nerve: injury to the ulnar nerve, which is located throughout the arm. The pain or numbness begins with the hands, being able to reach the elbow.
  • Peroneal nerve compression: This nerve is located in the lower leg. There is a loss of control and muscle mass in the ankles, feet, and legs.
  • Guillain-Barré syndrome: another of the diseases of the peripheral nervous system is the disorder in which the immune system itself mistakenly attacks the nerves. The first manifestations are tingling and weakness in the extremities, spreading rapidly and producing paralysis in the body. With treatment, most people recover from this syndrome.
  • Alcoholic neuropathy: it is due to nerve damage due to alcohol intoxication, as well as poor nutrition, characteristic of alcoholism. Symptomatology includes pain and weakness in the extremities.
  • Diabetic neuropathy: This disease of the peripheral nervous system develops due to nerve wear caused by high blood sugar levels. Symptoms manifest both in the extremities and in the face.

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