Peripheral Sensors

This page provides a summary of the main types of afferent axons in peripheral nerves for future reference. There is no need to memorize the list at this point, since we will be elaborating on each of them at some point. Because axons are long and thin, they are often called "fibers", although this is unfortunate, redundant terminology.

Skin Afferents

The figure to the right shows the main types of afferents from the skin:

Muscle Afferents

There are two major types of afferents from muscles we will be talking about. (There are also less specialized receptors that sense joint position and movement.)

Neurotransmitters of Afferent Neurons

The C fibers release glutamate. In this case, it can have both fast actions by binding to a five subunit ligand gated ion channel and slow actions actions by binding to an NMDA receptor. Also, these neurons release peptides, such as subtance P. More in lecture.

All of the myelinated afferent neurons release glutamate as their neurotransmitter, which acts as a fast neurotransmitter binding to the five subunit ligand-gated ion channel.