Somatic nervous system

The somatic nervous system (SNS) is a part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles. The SNS consists of afferent nerves or sensory nerves and efferent nerves or motor nerves.

Structure

The somatic nervous system is composed of nerves that connect the central nervous system (CNS) to the skin, sensory organs, and all skeletal muscles. It is responsible for nearly all voluntary muscle movements as well as for processing sensory information that arrives via external stimuli including hearing, touch, and sight.

Afferent Nerves

Afferent nerves, also known as sensory nerves, carry information from sensory receptors in the skin, muscles, and joints to the CNS. These nerves are responsible for transmitting sensations such as pain, temperature, and touch.

Efferent Nerves

Efferent nerves, also known as motor nerves, carry commands from the CNS to the muscles. These commands initiate muscle contraction and movement. The motor neurons in the SNS are responsible for the voluntary movements of the body.

Function

The primary function of the somatic nervous system is to connect the CNS with the body's muscles and skin, enabling voluntary movements and the reception of external stimuli. This system allows for activities such as walking, talking, and other conscious movements.

Neurotransmitters

The primary neurotransmitter of the somatic nervous system is acetylcholine. Acetylcholine is released at the neuromuscular junction, where it binds to receptors on the muscle fibers, causing them to contract.

Pathways

The pathways of the somatic nervous system are relatively straightforward. Sensory information is transmitted from the periphery to the CNS via sensory neurons. Motor commands are sent from the CNS to the muscles via motor neurons.

Clinical Significance

Disorders of the somatic nervous system can lead to a variety of clinical conditions. Damage to the sensory nerves can result in loss of sensation, while damage to the motor nerves can result in loss of muscle function or paralysis.

See Also

• Peripheral nervous system
• Central nervous system
• Autonomic nervous system
• Neuromuscular junction
• Motor neuron
• Sensory neuron

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