Sensory neurons

Sensory neurons or afferent neurons are neurons that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is known as sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord.

Structure

Sensory neurons are composed of four major parts: the dendrites, the soma, the axon, and the axon terminal. The dendrites receive sensory information, and the soma contains the nucleus and processes this information. The axon conducts messages, and the axon terminal interacts with its target.

Function

The primary function of sensory neurons is to transmit sensory data to the central nervous system from the body's sensory receptors. This data can include information about physical stimuli such as touch, temperature, and pain, or about the body's internal physiological state.

Types

There are several types of sensory neurons that correspond to different senses. These include:

• Nociceptors: These sensory neurons respond to damaging or potentially damaging stimuli by sending signals to the spinal cord and brain. This process, called nociception, usually causes the perception of pain.
• Thermoreceptors: These sensory neurons respond to changes in temperature.
• Photoreceptors: These sensory neurons respond to light and allow for the sense of vision.
• Mechanoreceptors: These sensory neurons respond to mechanical pressure or distortion. They include touch, pressure, vibration, proprioception, and hearing receptors.

Clinical significance

Damage to sensory neurons or the pathways they form can lead to symptoms such as pain, numbness, or paresthesia. Diseases such as diabetes mellitus can cause damage to sensory neurons and lead to diabetic neuropathy.

See also

• Motor neuron
• Interneuron
• Neuron doctrine
• Neuroscience