Definition:
The peripheral nervous system (PNS) is the network of nerves and ganglia that lie outside the central nervous system (CNS), which consists of the brain and spinal cord. It connects the CNS to the various organs, limbs, and other body parts.
Subdivisions of the Peripheral Nervous System:
- Somatic Nervous System (SoNS)
- Autonomic Nervous System (ANS)
- Sympathetic Nervous System
- Parasympathetic Nervous System
- Enteric Nervous System
Somatic Nervous System:
The somatic nervous system is responsible for controlling voluntary movements and relaying sensory information to the CNS. It consists of motor neurons that carry information from the CNS to the skeletal muscles, and sensory neurons that transmit information from the body to the CNS.
Autonomic Nervous System:
The autonomic nervous system regulates involuntary bodily functions and helps maintain homeostasis. It controls processes such as heart rate, digestion, respiration, and glandular secretion. The ANS is further divided into three subdivisions.
Sympathetic Nervous System:
The sympathetic nervous system prepares the body for stressful or emergency situations. It is responsible for the “fight or flight” response, increasing heart rate, dilating pupils, and releasing adrenaline.
Parasympathetic Nervous System:
The parasympathetic nervous system promotes relaxation and the restoration of bodily functions after a stressful event. It helps regulate activities like digestion, urination, and sexual arousal.
Enteric Nervous System:
The enteric nervous system (ENS) is a division of the ANS that specifically regulates the digestive system. It controls gut motility, secretion, and blood flow within the gastrointestinal tract.