UW Hist Wk3

function of neurons

signal transmission

function of glia

nourish and support neurons

efferent

away from CNS

afferent

towards CNS

multipolar neuron

motor neurons, interneurons

pseudo-unipolar neuron

sensory neurons

horn for sensory neurons

dorsal hornho

location of cell bodies of motor neurons

ventral horn

general sensory neuron

stimulus acts directly on receptor ending

special sensory neuron

stimulus acts on special sensory cell

slow axoplasmic (axonal) transport

stop-and-go cytosolic movementf

fast axoplasmic (axonal) transport

kinesin/dynein dragging vesicles across microtubules

dendrites

carry signal toward cell body

terminal arbors

carry signal away from cell body

signals neurotransmitter release into synaptic cleft

Ca2+ influx

active zone

location of exocytosis of neurotransmitter

peri-active zone

location of empty vesicle membrane recycling

central nervous system (CNS)

derived from neural tube: brain + spinal cord

peripheral nervous system (PNS)

derived from neural crest: nerves + ganglia

gray matter

cell bodies: information processing

white matter

myelinated axons: connecting cables

neuropil

neuron hairs

types of glia in CNS

astrocytes, oligodendrocytes, microglia, ependyma

astrocyte

controls blood flow to brain, maintains blood-brain barrier, recycles neurotransmitters, stores glycogen for neurons

ependyma

lines ventricles, produces and circulates cerebrospinal fluid

microglia

phagocytic; engulf infectious cells and other harmful substances

oligodendrocyte

myelinates and insulates axons in CNS

sensory ganglion

cluster of cell bodies just outside dorsal spinal cord

interneuron

located entirely in spinal cord gray matter

types of glia in PNS

satellite cells, Schwann cellssa

satellite cells

regulate nutrients and waste for cell bodies in gangliaSch

Schwann cell

myelinate axons in PNS

fascicle

bundle of axons & Schwann cells

endoneurium

surrounds individual Schwann cells

perineurium

surrounds fascicles

epineurium

ensheaths groups of fascicles

stages of peripheral nerve degeneration

1mm/day: Wallerian degeneration, growth cone, reinnervation