PNS diagramming

General Sensory characteristics

1 pseudounipolar neuron

Cell body in dorsal root ganglion or cranial nerve ganglion

Sensory from skin, muscle, bones track

follows nerves segmentally associated spinal nerves or cranial nerves

Sensory from viscera

Homeostasis follows parasympathetic

nociceptors follow sympathetic

General somatic pathways

1 LMN

Cell body resides in brainstem or spinal cord segment (must memorize location)

All follow ventral horn, ventral root, spinal nerve

Somatic epaxial pathway

dorsal branch

Somatic hypaxial muscles

ventral branch

Motor sympathetic (visceral)

2 motor neurons

smooth muscle, cardiac muscle, glands

Sympathetic neuron one

preganglionic

cell body in lateral horn of thoracolumbar spinal cord

(estimate general location close to organ)

Ventral root- spinal nerve- communicating branch- neuron 2

Sympathetic neuron 2

post ganglionic

cell body in sympathetic ganglion closest to target organ

Axon follows preexisting nerves or course directly to organ forming nerves

Parasympathetic

head, neck, thorax, abdomen

or pelvis (we don’t learn yet)

Parasympathetic neck, head, thorax, abdomen Neuron 1

Neuron 1 in brainstem

axon follows cranial nerves 3,7,9,10

Parasympathetic neck, head, thorax, abdomen Neuron 2

In ganglion close to or within organ

axon very short