Free nerve ending

Blausen 0803 Skin FreeNerveEndings

Type of nerve ending in the skin and other tissues

Free nerve ending

System	Peripheral nervous system
Location	Skin, mucous membranes, muscles, joints, viscera

A free nerve ending is a type of sensory receptor found in the skin, mucous membranes, muscles, joints, and viscera. These nerve endings are responsible for detecting a variety of stimuli, including pain, temperature, and mechanical changes.

Structure

Free nerve endings are characterized by their lack of specialized structures. Unlike other sensory receptors, such as Pacinian corpuscles or Meissner's corpuscles, free nerve endings do not have a complex encapsulation. They are simply the terminal branches of afferent nerve fibers that penetrate the epidermis and end in the dermis.

Function

Free nerve endings play a crucial role in the detection of various types of stimuli:

• Nociception: They are primary receptors for pain and can be activated by mechanical, thermal, or chemical stimuli.
• Thermoreception: They detect changes in temperature, with different free nerve endings responding to either hot or cold stimuli.
• Mechanoreception: Some free nerve endings are sensitive to mechanical changes, such as pressure and touch.

Location

Free nerve endings are widely distributed throughout the body. They are found in:

• The epidermis and dermis of the skin
• Mucous membranes lining various cavities
• Muscles and joints, where they contribute to proprioception
• Viscera, where they can detect internal pain and other stimuli

Clinical significance

Damage or dysfunction of free nerve endings can lead to various sensory disorders. For example, neuropathic pain can result from the abnormal activation of these receptors. Understanding the role of free nerve endings is crucial in the development of treatments for pain management and sensory dysfunction.

See also

• Nociceptor
• Thermoreceptor
• Mechanoreceptor
• Peripheral nervous system
• Sensory receptor