Peripheral nervous system

The peripheral nervous system (PNS) is an extensive network of nerves that connects the brain and spinal cord to every organ, muscle, and tissue in the body. It transmits commands from the central nervous system (CNS) to the body and returns sensory information about what is happening in the internal and external environment.

Thanks to the PNS, a person can feel pain, heat, cold, movement, as well as control muscles and internal organs.

Structure of the Peripheral Nervous System

The PNS consists of nerve fibers and nerve nodes (ganglia) located outside the brain and spinal cord. It is divided into two major parts: the somatic and autonomic (vegetative) nervous systems.

Somatic Nervous System

The somatic part is responsible for conscious, voluntary actions and the perception of sensations. Through it, a person can control their movements, coordinate muscles, and receive signals from the sensory organs.

• Motor nerves transmit impulses from the brain and spinal cord to skeletal muscles, causing them to contract;
• Sensory nerves deliver information about touch, temperature, pain, and body position in space to the brain.

Autonomic (Vegetative) Nervous System

This part of the PNS manages involuntary functions of the body that occur without conscious involvement: heart function, breathing, digestion, hormone secretion, blood pressure, and body temperature.

It is divided into two complementary systems:

1. The sympathetic system activates the body in stressful situations, preparing it for action: it increases heart rate, raises blood pressure, speeds up breathing, and redistributes blood flow to the muscles;
2. The parasympathetic system promotes recovery and rest: it reduces heart rate, improves digestion, and activates tissue repair processes.

Functions of the Peripheral Nervous System

The PNS performs numerous essential tasks, ensuring constant interaction between the body and the brain.

• Transmits sensory signals from the skin, joints, internal organs, and sensory receptors to the CNS;
• Transmits motor impulses from the CNS to the muscles, ensuring movement and coordination;
• Regulates the function of internal organs through autonomic pathways, maintaining homeostasis;
• Provides feedback, allowing the brain to assess the body’s condition and adjust responses.

Common Diseases of the Peripheral Nervous System

Peripheral nerves are vulnerable to damage, inflammation, infections, and metabolic disorders. PNS disorders can cause loss of sensation, pain, weakness, or dysfunction of internal organs.

The following diseases of the PNS are identified:

• Neuropathy – damage to peripheral nerves, often associated with diabetes, toxins, or injuries; manifests as burning, numbness, and pain;
• Myasthenia – an autoimmune disease that disrupts signal transmission between nerves and muscles, causing rapid fatigue and weakness;
• Carpal tunnel syndrome – compression of the median nerve in the wrist area, leading to pain, tingling, and numbness in the fingers;
• Radiculopathy – compression of spinal nerve roots, causing pain that radiates to the limbs;
• Polyneuropathy – multiple inflammation of peripheral nerves, often accompanied by coordination and motor function disturbances.

Conclusion

The peripheral nervous system is a communication channel between the brain and the body, providing sensitivity, movement, and internal balance of the organism. Its coordinated work is essential for the normal functioning of all organs.

Disorders in the PNS can manifest with a wide range of symptoms – from numbness and muscle weakness to heart rhythm disturbances. Therefore, maintaining the health of the nervous system requires a balanced diet, adequate sleep, physical activity, and protection from stress and toxins.