Class #10-Somatic & Visceral Sensation, p. 1 (Image from: Exduck.com/esxpage/useful stuff.htm) Functions: SOMATOVISCERAL SENSATION.

Class #10-Somatic & Visceral Sensation, p. 1

(Image from: Exduck.com/esxpage/useful stuff.htm)

Functions:

SOMATOVISCERAL SENSATIONSOMATOVISCERAL SENSATION

Class #10-Somatic and Visceral Sensation, p. 2

Aβ

Aδ

C

Receptors (and their axons):

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)

Cell bodies for nearly all bodily receptors (i.e., from skin, muscle and viscera) are located in dorsal root ganglia. For the head, receptor cell bodies are in the trigem-inal ganglion (5th cranial n.). Most internal organs also have sensory recep-tors. The cell bodies of those receptors are loca-ted in the vagus nerve’s ganglion (the ‘nodose ganglion’ – see slide 7).

Class #10-Somatic and Visceral Sensation, p. 3

Receptors (cont’d):

Adequate stimuli:

Sensitivity:

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)

Class #10-Somatic and Visceral Sensation, p. 4

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)

Submodalities:

Submodality coding:

Afferent nerves: spinal nerves (from the body) and the trigeminal nerves (from the head)*

For SKIN AND MUSCLES, the input is arranged in a highly topographically organized manner – caudal to

rostral

Class #10-Somatic and Visceral Sensation, p. 5

* Remember DERMATOMES? - an area of skin innnervated by sensory fibers in a single spinal nerve]

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)

SKIN AND MUSCLES—Afferent nervesSKIN AND MUSCLES—Afferent nerves

Trigemnial n. and ganglion (face)

S4

C5

T8

Class #10-Somatic and Visceral Sensation, p. 6

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)

INTERNAL ORGANS (output to them from INTERNAL ORGANS (output to them from CNS)CNS)BUT, for VISCERA (internal organs), the situation is

complicated by the organization of the nerve supply to internal organs. Each organ is supplied by both

sympathetic and parasympathetic EFFERENT nerve fibers.

(See pages 85-87 (“The Autonomic Nervous System”) in your text for an explanation of the function of the efferent fibers in these nerves –that is, functions of the fibers that come from the CNS to each internal organ.)

vagus n.

Afferent nerves: VISCERA (cont’d)

Afferent fibers from internal organs travel with both the sympathetic and parasympathetic nerves. Thus, many internal organs send input both to the spinal cord (where there is some caudal to rostral organization), and to brain via the vagus nerve.

Class #10-Somatic and Visceral Sensation, p. 7

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)

INTERNAL ORGANS INTERNAL ORGANS ((Afferent nervesAfferent nerves: sensory : sensory input from them to CNS)input from them to CNS)

nodose ganglion

dors

al ro

ot

gan

glia

dors

al ro

ot

gan

glia

dorsal root ganglia

vagus n.

AFFERENT NERVES (cont’d): VISCERA

You can see the effect of this double innervation on topographic organization of input to CNS from visceral afferent nerves by looking at the two inputs superimposed. (Note: red is sympathetic; green is parasympathetic.)

Class #10-Somatic and Visceral Sensation, p. 8

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)

S1-S5

L2-L4

Class #10-Somatic and Visceral Sensation, p. 9

Main CNS routes of somatovisceral information

SOMATOVISCERAL SENSATION (cont’d)SOMATOVISCERAL SENSATION (cont’d)