BIOSCI 107 nervous tissue

CNS

brain, spinal cord (and optic nerve)

PNS

Nervous tissue outside of CNS

Activities of the nervous system

sensory, integrative, motor

Sensory activity

Detection of external and internal stimuli

Integrative activity

analysis and storing of information

Motor activity

Stimulation of effectors (e.g. muscles and glands)

Nervous tissue 2 cell types

neurons and neuroglia

Neuron basic structure

cell body (soma), dendrites, axon

Dendrites

receive nerve impulses/action potentials

Axon

carries nerve impulses away from the cell body

4 kinds of neurons

Multipolar, bipolar, unipolar, anaxonic

multipolar neuron structure

several dendrites and one axon

multipolar neuron function

motor neurons

Bipolar neuron structure

one dendrite and one axon, soma in the middle

Bipolar neuron function

special senses

unipolar neuron structure

continuous axons and dendrites, soma off to the side

unipolar neuron function

most sensory neurons

anaxonic neuron structure

Can't distinguish axons from dendrites

Main differences between neuroglia and neurons

Neuroglia are smaller but more numerous and can divide while neurons can't.

CNS neuroglia

astrocytes, oligodendrocytes, microglia, ependymal cells

Astrocytes structure

star shaped

Astrocytes function

maintain the blood-brain barrier, surround CNS neuron cell bodies for support and fluid exchange

oligodendrocytes function

myelinate neurons in the CNS

What is myelin

lipid sheath around the axons for insulation which increases the speed of action potentials

Microglia function

phagocytosis

ependymal cells structure

cuboidal/columnar epithelial cells with cilia and microvilli

ependymal cells location

line ventricles of brain and central canal of spinal cord

ependymal cells function

produce cerebrospinal fluid, movement by cilia

PNS neuroglia

Schwann cells and satellite cells

Schwann cells function

form myelin sheath in PNS

Satellite cell function

surround PNS neuron cell bodies for support and fluid exchange

Difference between Schwann cells and oligodendrocytes

Schwann cells can myelinate only one neuron while oligodendrocytes can myelinate multiple