Chapter 11

jennraq2u's version from 2015-07-25 20:10


Question Answer
Neuroglia aka Glial Cells p. 347"Glue" scaffolding that suuports neurons
Neuronnerve cells transmit and generate signals for Nervous system
microglial cellsmonitor health of nearby neurons
astrocytes"Star" like. most abundant. Anchor neurons to nutrient supply lines
ependymal cellswrap garmet like permeable barrier between brain/spinal cord and CSF
oligodendrocytesfewer brancehs than "astrocytes".Wraps its process =myelin sheath
shwann cells AKA neurolemmocytessurrond ALL nerve fibers in PNS with myelin sheaths
satellite cellsfunction like "astrocytes" except in the PNS.
perikaryon AKA SOMAcytoplasm surrond nucleus of neuron cell body
chromatophilic substance/ Nissl bodiesstains darkly with color dies. AKA Rough ER of nerve cell
neurofibrilsbundles of intermediate filaments/neurofilaments ; maintian shape
plasma membranepart of receptive region recieving messages
nucleiclusters of cell bodies in CNS
gangliaclusters of cell bodies in PNS
Tractsbundles of neuron processes in the CNS; CNS has cell bodies & tracts
nervesbundles of neuron processes in PNS; chiefly all that is in the PNS
dendrites (main receptive input region)mesages/electrical signal TOWARD cell body;branch part of motor neuron
Axon (Long ones AKA NErve Fiber)neuron process that carries impulses AWAY from cell body; efferent process; conductory region p. 350
myelin sheathincreases speed of nerve impusle transmission; These are never on Dendrites; Dendrites=NONmylenated
white matterparts of spinal cord/brain wtih dense collections of myelinated fibers
gray matterMostly has nerve cell bodies & NONmyelinated fibers
multipolar neurons3 or more process=1 axon & rest Dendrites (most common neuron type)
Bipolar neurons2 process= 1 axon & 1 dendrite; rare in the body
Unipolar neruonshas a peripheral process & central process; found in ganglia of PNS as sensory neurons
sensory/afferent neuronstransmit impulse TOWARD or into the CNS; with 1 exception, ALL sensory neurons are unipolar; bodies outside of CNS
motor/efferent neuronscarry impulses AWAY from CNS to effector Organs; MUltipolar; With 1 exception, Bodies are all located Inside of CNS
Interneuronslie between motor & sensory neurons; shuttle signals thru CNS pathways r/t integration; confined w/in CNS; Multipolar
resting membrane potentialvoltage across plasma membrane during resting state of excitatable cell; ranges from -40 to 90
At Resting Membrane Potentialthe Neg interior of cell is r/t to a much greater ability for K+ to diffuse OUT of cell than for Na+ to diffuse INTO cell
depolorizationINCREASE in membrane potential; inside of membrane moves closer to 0 or above & =(+); becomes LESS negative
hyperpolarizationDECREASE in membrane potential; inside of membrane moves further from 0 than resting potential; MORE negative
graded potentialchange in membrane potential that varies directly with the strength of stimulus & declines w/ distance
postsynaptic potentialNeurotransmitter is released into a fluid filled gap called a synapse & it influences the neuron beyond (post) the synapse
excitable membranesneurons & muscle cells (only these kidn can generate action potential)
action potentialplarity reversral conducted along membrane of a muscell cell or nerve fiber; generated ONLY in axons
Explsive Positive feedback of Na+ rushing into cellresponsible for rising (depolarization) phase of action potential (p.359)
repolarizationCaused by abrupt decline in Na+ and increased permeability of K+; membrane potential returns 2 intial restng (polarized) state (ONly restores resting ELECTRICAL conditions)
stimulus intensitycoded by frequencey of action poetentials NOT increases in strength of individual APs
Abosulte Refractory Periodtime follwoing stumualtion during which NO Additional AP can be evoked
Relative Refractory PeriodThreshold for AP stiumulation is elevated; exceptionally strong stimulus can re-open Na+ channels
Rate of Impulse PropogationR/T 1) Axon (size) Diameter & 2) Degree of myleination (Non-myleinated= SLOWER)
saltatory conductionAP moves along myleinated fiber in which nerve impusle appears to leap from gap to gap
Group A fiberLargest diameter; somatic sensory & motor fibers r/t SKIN, Muscles, & joints; THICK myelin sheaths
Group B fiberIntermediate diameter; lightly myleinated (p.365)
Group C fibersmallest diameter; non-myelinated/ Incabable of sltatotry conduction; condcut impulses @ leisurely pace
synapsejunction or point of close contact between 2 neurons OR between neuron & an effector cell
presynaptic neuronconducts impulses TOWARD the synapse (sends)
Postsynaptic neurontransmits electrical signal away from the synapse (recieves)
electrical synapses :purely electrical
Question Answer
chemical synapsesconvert electrical signals to chemical signals &(neuro-Ts) travel across synapse to postsynaptic cells where they are converted back into electric signals
synaptic delay
Postsynaptic membranesDo not generate APs; only ESPSs occure at excicatotory pst synatpic membranes
axons havevoltage gated channels
ISPSNeuro-Ts hyperpolarize postsynaptic smembrane making it more permeable to K+ or CL-; Na+ is NOT affected (p. 371)
Most effective synapes :ISPSs b/t site of excitatotory inputs & closest to axon hillock
Question Answer
synpatic potentationR/T repeated use of synapes= enhances the presynaptic nerons ability to excite the postsynaptic neuron
presynaptic inhibitionrelease of excitatory Neuro-T by 1 neuron is inhbited by the activity of another neuron via axoaxanal synapse
funtion of neur-Tdepends on recpetor that it interacts with
nueromodulatorchemical messenger released by a neuronthat does nto directly cause ESPSs or IPSPs; instead affects strength of synapitc transmission
neural integrationp.378
circuitspatterns of synatic connections in neuronal pools
reflexesautmatic reaction stimuli
reflex arcsneural pathways where reflexes occure; have 5 components p. 379
Membrane potentialsvoltage across plasma membrane
Postsynaptic potentialsa graded potential r/t stimulus is a Neuro-T released by a another neuron
synaptic integrationp.369
Neurotransmitters and their receptorsp. 373