Afferent nerve fiber

Afferent ( " to take to him, out " of Latin affere ) are called nerve cells on the flow to a certain area signals neurophysiological those extensions. This general labeling according to the direction of the signal line can be used for different structures at different levels.

At the cellular level in relation to the nerve cell body, the dendrites are called afferent. At the regional level, based on a specific region of the brain called each afferent pathways also afferents in contrast to the outgoing efferent fibers.

At the systemic level are related to the central nervous system (CNS) the entering nerve fibers that come through which signals are collectively referred to as afferent nerve fibers or " afferent " and divided into somatic and visceral. These are efferent fibers compared to the signal output. As components of a reflex arc is ever spoken of afferent or efferent limb.

Afferents to the CNS

The totality of the periphery of entering the central nervous system and in this direction the signals from the central nervous system receptors or from sensory organs afferent nerve fibers also called afferents. The nerve cells are involved as afferent neurons in each part of an afferent system.

In the German anatomy is often distinguished for afferents in higher animals and man, between

• Sensitive - the surface sensitivity and depth sensitivity for the haptic perception
• And sensory - for olfactory, visual, auditory and gustatory senses,

Even if this subdivision is often otherwise justified as the fact that the latter are restricted to very limited areas of the body. Among vertebrates, the afferents by some authors are further subdivided, although the demarcation is also not always plausible.

The somatic afferents (from Latin soma " body " ) derive information of the body and part of the somatic nervous system. Here are general somatic afferents (ASA, Eng. General somatic afferent, GSA) and special somatic afferent (SSA, Eng. Somatic afferent special ) distinguished. The ASA are all paths of haptic perception ( sensation of touch, temperature perception, pain perception, proprioception ), counted the paths of sight, hearing and sense of balance to the SSA.

The visceral afferents (from Latin viscera, " entrails " ) are those of the autonomic nervous system and transmit information from the internal organs to the central nervous system. Here are some general (AVA, Eng. GVA) distinguished and special (SVA ). AVA conduct pain sensations, chemical and mechanical stimuli from the organs to the brain, the SVA smell and taste perceptions.