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histo block 1/2 sem 1
nerv tissue
12
Other
Professional
05/31/2007

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Term
nissl substance
Definition
abundant RER in neurons
in cell body and dendrites- not axons
Term
neurons
Definition
cell body- nucleus/organelles
axon-long process reach distant cells- output
dendrites-short processes for input
synapses-special cell junctions
Term
multipolar neuron
Definition
single axon-lots dendrites-MOTOR neurons
Term
sensory neuron
Definition
pseudounipolar- located in dorsal root ganglia: one to CNS, one to periphery
Term
interneuron
Definition
bipolar- mostly communicating-connect two groups of neurons
Term
neuron signaling
Definition
ionic gradient across membrane
firing with depolarization -rest -70mv
depolar from + ion entering cell membrane and make less negative

hyperpolarization makes membrane potential more negative
-happens when negative ions ENTER

outward current + ions causes hyperpolarization (or cl- enter)
Term
ion channel proteins
Definition
ligand gated-chem transmitt substance
voltage gated- respond to depolarization, all or none response large signal and Na and K channels open lead to explos chg in act potent
Term
synapses
Definition
terminal end of axon swollen form bouton

-close to target cell with 20nm synaptic cleft gap

-neurosecretory granules released in cleft and bind to postsynaptic membrane and cause chg in act potent of postsynaptic membrane
excit or inhib
Term
release of transmitter
Definition
depolarization- bind to ligand gated receptor
Na channel open lead to act potent

hyperpolarization-bind ligand gated recept, sm - ions inhibit neuron
lead to depression
(gamma amino butyric acid and glycine are inhibitor neurotransmitters)
Term
synapse types
Definition
axosomatic/axodendritic(most common)/axoaxonal (excit or inhibit)
Term
myelin
Definition
oligodendrocytes CNS-multiple axon
schwann in PNS- one axon

insulate nerve- speed nerve transmisison- prevent leak of act potent

spiral layer cell membrane wrappped round axon
-bound by adhes molecules
Term
special adhesion molecules myelin
Definition
PO protein in PNS
Proteolipid proteins in CNS- bind to exoplasmic sufaces of myelin membrane-
myelin basic protein to cytoplasmic surfaces
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