Neuropathy : Peripheral neuropathy

Описание: The peripheral nervous system (PNS) is the part of the nervous system that lies outside the brain and spinal cord (the central nervous system, CNS).

🔹 Components of the PNS
1. Cranial nerves – 12 pairs that emerge directly from the brain (e.g., optic nerve, vagus nerve).
2. Spinal nerves – 31 pairs that emerge from the spinal cord.
3. Ganglia – clusters of nerve cell bodies located outside the CNS.
4. Peripheral nerves – bundles of axons that connect the CNS to organs, muscles, and skin.

🔹 Divisions of the PNS
1. Somatic Nervous System (SNS)
• Controls voluntary movements of skeletal muscles.
• Mediates conscious sensation (touch, pain, temperature, proprioception).
2. Autonomic Nervous System (ANS)
• Controls involuntary functions (heart rate, digestion, respiration, glandular activity).
• Further divided into:
• Sympathetic – “fight or flight” (increases heart rate, dilates pupils, mobilizes energy).
• Parasympathetic – “rest and digest” (slows heart rate, promotes digestion, energy storage).
• Enteric nervous system – regulates gastrointestinal function.

🔹 Functions of the PNS
• Connects the CNS to the rest of the body.
• Carries sensory information from body → CNS.
• Carries motor commands from CNS → muscles/glands.
• Regulates involuntary functions via the ANS.

🔹 Clinical relevance

Damage to the PNS can lead to:
• Peripheral neuropathy (numbness, tingling, weakness).
• Nerve compression syndromes (e.g., carpal tunnel syndrome).
• Autonomic dysfunction (abnormal sweating, BP regulation problems).