Peripheral nervous system
What is the Peripheral Nervous System?
The portion of the nervous system that includes nerves and ganglia outside of the brain and spinal cord is known as the Peripheral Nervous System (PNS). It is in charge of sending sensory and motor impulses between the central nervous system (CNS) and the limbs, organs, and tissues. It contains all the nerves that connect the brain and spinal cord to the rest of the body.
Type of Peripheral Nervous System
All of the nerves and ganglia outside of the brain and spinal cord make up the PNS. The somatic nervous system and the autonomic nervous system are its two branches.
1. Somatic nervous system
The somatic nervous system is a branch of the peripheral nervous system that regulates feelings and voluntary movements. It is made up of motor neurons, which regulate the skeletal muscles, and sensory neurons, which sense inputs like touch, temperature, and pain. The somatic nervous system is in charge of reflex behaviours like moving your hand away from a hot stove. Through the spinal cord, the brain receives the sensory data, processes it, and then produces a response. Walking and participating in sports are both daily activities that need the somatic nervous system, which is also involved in learning and memory.
2. Autonomic nervous system
The autonomic nervous system (ANS), a division of the peripheral nervous system, regulates bodily processes including heartbeat, digestion, breathing, and glandular production. It operates automatically, without conscious effort, and controls physical activities based on the environment both within and outside the body.The sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) are two of the ANS's subsystems.
- Sympathetic nervous system
The "fight or flight" reaction to perceived dangers or stresses is controlled by the sympathetic nervous system, a component of the autonomic nervous system. It causes physiological reactions such an increase in heart rate, pupil dilation, and blood pressure, preparing the body to either face the threat or flee from it. Other internal processes including digestion, breathing rate, and body temperature are all regulated by the sympathetic nervous system. Hypertension, anxiety, and post-traumatic stress disorder have all been associated with dysregulation of the sympathetic nervous system.
- Parasympathetic nervous system (PNS)
The PNS is in charge of controlling the body's relaxation and digestion processes. The heart rate is slowed, digestion is boosted, and relaxation is encouraged. By slowing down the body's metabolism, the PNS also aids in energy conservation. The body is able to return to a peaceful condition following a period of stress or activity because to the activation of this system, which occurs during periods of rest and relaxation. In order to sustain general health and wellbeing, the PNS is essential.
Cranial Nerves and Spinal Nerves
While spinal nerves come out from the spinal cord and regulate the rest of the body, cranial nerves come out from the brainstem and supply the head and neck.
Cranial Nerves
There are 12 pairs of cranial nerves, and they are each given a name based on what they do or what part of the body they innervate. As follows:
1. Olfactory nerve - in charge of the sense of smell.
2. Optic nerve - in charge of eyesight.
3. Oculomotor nerve - accountable for causing eye movement and pupil dilation.
4. Trochlear nerve - accountable for eye motion.
5. Trigeminal nerve - responsible for the jaw, head, and facial muscles' feeling.
6. Abducens nerve - responsible for eye movement.
7. Facial nerve - responsible for taste, facial expression, and the production of tears and saliva.
8. Vestibulocochlear nerve - accountable for balance and hearing.
9. Glossopharyngeal nerve - is in charge of taste, swallowing, and saliva production.
10. Vagus nerve - responsible for controlling autonomic processes including breathing, digestion, and heart rate.
11. Accessory nerve - able to move the neck and shoulders.
12. Hypoglossal nerve - is in charge of tongue movement.
Spinal Nerves
The names of the 31 pairs of spinal nerves correspond to where they are situated on the spinal cord. As follows:
1. Cervical nerves (C1-C8) - innervate the neck and upper extremities.
2. Thoracic nerves (T1-T12) - innervate the chest and abdominal muscles.
3. Lumbar nerves (L1-L5) - innervate the lower back and legs.
4. Sacral nerves (S1-S5) - innervate the buttocks, genitals, and legs.
5. Coccygeal nerve (Co1) - innervates a small area of skin around the coccyx.
Each spinal nerve has a dorsal (sensory) root and a ventral (motor) root, which merge to form a mixed spinal nerve. These nerves carry both sensory information from the periphery to the CNS and motor signals from the CNS to the muscles.
In sum, by relaying signals from the brain to the rest of the body, spinal nerves and cranial nerves both play crucial functions in the nervous system.
How Does the Peripheral Nervous System Work?
The brain and spinal cord receive information from sensory receptors through the PNS, which then transmits instructions to the relevant muscles or organs. The electrical signals known as nerve impulses, which travel the whole length of a neuron, are responsible for this communication.
When a sensory receptor is triggered, like when touching a hot stove is done, the receptor sends a signal to the spinal cord through a sensory neuron. The brain then receives the information from the spinal cord, processes it, and sends a command to the motor neurons in the muscles to pull the hand away from the stove.
Similar processes occur in the autonomic nervous system, which regulates involuntary processes like breathing, heart rate, and digestion rather than voluntary actions. For instance, the sympathetic nervous system is triggered when a person is afraid, which raises their heart rate and gets them ready for a fight-or-flight reaction.
Why is the Peripheral Nervous System Important?
Our existence and the health of our bodies depend on the PNS. Without it, we would be unable to move, feel, or perform many of the essential functions that sustain life. It enables us to react to the world around us and to change with the environment.
Disorders of the Peripheral Nervous System (PNS)
PNS disorders can impact any aspect of this system and present with a variety of symptoms. Here are a few instances of PNS disorders:
1. Peripheral neuropathy: In this condition, the nerves that carry signals from the brain and spinal cord to the rest of the body are damaged. This may result in weakness, tingling, numbness, and discomfort in the afflicted regions.
2. Guillain-Barre syndrome: In this uncommon illness, the immune system targets the PNS nerves. It may result in respiratory failure as well as paralysis and muscular weakness.
3. Charcot-Marie-Tooth disease: The nerves that regulate the muscles in the hands, feet, and lower legs are impacted by this genetic illness. It may result in walking difficulties, deformed feet, and muscular weakness.
4. Chronic inflammatory demyelinating polyneuropathy (CIDP): In this uncommon condition, the immune system targets the myelin coating that protects PNS nerve fibres. It may result in tingling, numbness, and weakening of the muscles.
5. Radiculopathy: This is a disorder when the spinal cord-extension nerves' roots become irritated or squeezed. The areas that are impacted may experience discomfort, numbness, and weakness.
symptoms of Peripheral Nervous System (PNS)
PNS problems can cause a variety of symptoms, depending on the particular ailment, however some typical ones are as follows:
1. Numbness or tingling in the extremities
2. degeneration of muscles or atrophy
3. Muscle discomfort or cramping
4. loss of balance or coordination
5. speaking or swallowing challenges
6. impaired hearing or vision
7. respiratory issues or lack of breath
8. digestive issues like diarrhoea or constipation
9. alterations in heart rate or blood pressure
10. Skin modifications like rashes or skin discolouration.
It's crucial to consult a doctor if you have any of these symptoms so that you can receive the correct diagnosis and care.
diagnose of Peripheral Nervous System (PNS)
The following are typical actions a medical professional could take to identify a PNS disease:
1. Medical history: The patient will be questioned by the healthcare professional on their symptoms, how long they have been present, and any prior illnesses or procedures. They could also ask if the patient has a family history of neurological conditions.
2. Physical examination: In order to evaluate muscular strength, reflexes, coordination, and sensitivity, the healthcare professional will conduct a physical examination. Additionally, they might look for any muscle weakness or wasting.
3. Electromyography (EMG): A diagnostic procedure called an EMG monitors the electrical activity of the muscles and nerves. This examination can assist diagnose nerve injury and pinpoint its exact location and degree.
4. Nerve conduction studies (NCS): The nerves' electrical impulses are measured using NCS for their strength and speed. By locating and assessing the damage, this test can assist diagnose nerve injury.
5. Blood tests: Blood tests can be used to diagnose several PNS conditions, including autoimmune illnesses and infections that impact the nervous system.
6. Imaging tests: To detect structural anomalies in the nerves or surrounding tissues, imaging exams like computed tomography (CT) or magnetic resonance imaging (MRI) scans may be utilised.
7. Biopsy: To confirm the diagnosis, it may occasionally be required to take a biopsy of the afflicted nerve.
Treatment of Peripheral Nervous System (PNS)
The underlying the cause and the precise symptoms of PNS diseases determine the appropriate course of treatment. The PNS might be able to heal itself in some circumstances over time, but in other circumstances, medical attention could be required. Here are a few typical PNS disorder treatments:
1. Medications: PNS problems can be treated with a variety of pharmaceuticals, including painkillers, anti-inflammatory agents, and corticosteroids. These drugs can lessen PNS condition symptoms like pain, inflammation, and other symptoms.
2. Physical therapy: People with PNS disorders can benefit from physical therapy by having stronger muscles, a wider range of motion, and better balance. To assist the patient in regaining function and minimising discomfort, a physical therapist might create a personalised exercise programme.
3. Surgery: Surgery may occasionally be required to address PNS problems. For instance, surgery can be necessary to remove a tumour that is pushing on a nerve or to fix a traumatised nerve.
4. Nerve stimulation: Techniques for nerve stimulation, such as transcutaneous electrical nerve stimulation (TENS) or peripheral nerve stimulation (PNS), can assist those with PNS problems by reducing discomfort and enhancing muscular function.
5. Complementary therapies: For some persons with PNS issues, complementary treatments including acupuncture, massage, and yoga may also be beneficial. These treatments can aid in easing pain, enhancing relaxation, and enhancing general wellbeing.
Conclusion
The peripheral nervous system, which is an essential component of our entire nervous system and enables us to feel and react to the environment around us, is summarised above. We can better appreciate the part it plays in preserving the health of our bodies by comprehending how it functions and the significance of it.