PNS pathways

neural tube

CNS (Brain and spinal cord)

neural crest

PNS (sensory ganglia, sympathetic chain, adrenal medulla, Schwann cells)

dorsal root

sensory only

ventral root

motor only

spinal nerve

mixed sensory plus motor

Doral rami

epaxial muscles (deep back)

ventral rami

hypaxial muscles (limbs and body wall)s

sympathetic

thoracolumbar (T1-L2, later horn)

parasympathetic

craniosacral (cranial nerves + s2-s4)

preganglionic sympathetic fibers

short, myelinated (white rami)

postganglionic symopatheric fibers

long, unmyolinated (grey rami)

preganglionux parasympatgetic fibers

long postganglionic short

dorsal root ganglia

sensory neuron cell bodies

sympathetic chain ganglia

alongside vertebral column, fight/flight relay

pre aortic ganglia

in abdomen near aorta (Celiac, superior/inferior mesenteric)

enteric ganglia

in gut wall, regulates digestion

somatic motor neurons

→ ventral horn

ventral horn

→ skeletal muscle

visceral sensory neuros

→dorsal root ganglia

dorsal root ganglia

→ spinal cordre

referred pain

visceral afferents converge with somatic afferents at the same spinal cord level

sweat glands innervated by

sympathetic fibers

dura mater

outmost, tough

arachnoid

middle, CSF flows in subarachnoid space

pia matter

innermost, clings to CNS surface