nervous tissue I

• receptive area in multipolar neurons • most protein synth done here • membrane specialized for impulse generation

basophillic clump of rER in neurons

euchromatic with a central nucleolus that’s spherical and dense

• no, no mitosis - exception is neural stem cells- turn themselves into neurons when there is damage

intermediate filaments, microfilaments, microtubules

origin of the axon, funnel shaped with no rER- pale staining

dissolution of nissel bodies (accum of rer)

• radiate from soma • increase receptive area of neuron • antennas for info that they bring to cell body and then send down the axon • NEVER mylinated • no Golgi, may have RER, ribosomes, mitochondria

• no rer • has mitochondria, ser, vesicles microtubules and neurofilaments • transmit impulse from cell body to other neurons or muscle cells

axon cell membrane

axon cytoplasm

• distal to cell body but proximal to where it is myelinated - action potential initiated here

branches near hillock

the proximal portion regenerates distal degenerates

end of axon where there is a split into branches

little dilated ends of arborizations (lil feet) form synapses some local protein snyth occurs here

• movement of macromolecules, organelles and vesicles from/to axon cell body • can be anterograde or retrograde

• requires KINESIN (microtubule) • slow transport- carries substances from the cell body to the terminal buttons; for actin molecules, neurofilament proteins and tubulin molecules • fast- requires ATP

• carries macromolecules, organelles and vesicles TO the cell body • requires DYNEIN (microtubule) • VIRUSES AND TOXINS THAT ENTER NERVE ENDINGS TRAVEL TO THE CNS VIA RETROGRADE TRANSPORT • FAST TX- bidirectional and requires ATP • carries ser, synaptic vesicles, mitochondria, sugars neurotransmitters and calcium

• two processes - in special senses- smell vison hearing equilib

single process arising from cell body which secondarily bifurcates into 2 processes t shaped impulses transported down axon bypassing the cell body in CN sensory ganglia and Dorsal root ganglia

• most common kind • numerous dendrites and central process of axon • includes motor and interneurons

1)motor efferent -skeletal motor-somatic efferent- skeletal muscle fibers -visceral motor- visceral efferent-smooth muscle/cardiac 2) -sensory afferent - somatic= receive sensory from stimuli in environ visceral- from visera 3) interneurons- confined to CNS

• provide physical and physiological support for nerve cells • more numerous than nerve cells • can divide so can form tumors