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60 Cards in this Set

  • Front
  • Back
chemical messengers (hormones) delivered to the blood stream
3 basic steps of nervous system
-sense organs receive info
-brain and spinal cord determine responses
-brain and spinal cord issue commands to glands and muscles
Central Nervouse system
(CNS) brain and spinal cord enclosed in bony coverings
Bundle of axons in connective tissue
swelling of cell bodies in a nerve
sensory neurons
(afferent) detect changes in body and external environment. information transmitted into brain or spinal cord
(association neurons)Lie between sensory and motor pathways in CNS. 90% of our neurons are interneurons. process, store and retrieve information
motor neuron
(efferent) send signals out to muscles and gland cells. Organs that carry out responses called effectors
(irritability)ability to respond to changes in the body and external environment called stimuli
produce traveling electrical signals
when electrical signal reaches end of nerve fiber, a chemical neurotransmitter is secreted
Multipolar neuron
Most common. many dendrites/one axon
bipolar neuron
one dendrite/ one axon
olfactory, retina and ear
anaxonic neuron
many dendrites/no axon
help visual processes
fast anterograde axonal transport
either direction up to 400mm/day for organelles, enzymes, vesicles, and small molecules
fast retrograde axonal transport
for recycled materials and pathogens
slow axonal transport
(axoplasmic flow) moves cytoskeletal and new axoplasm at 10mm/day during repair and regeneration in damaged axons
form myelin sheaths in CNS
Ependymal cells
line cavities and produce CSF
(microphages) formed from monocytes in areas of infection, trauma and stroke
most abundant glial cells. form framework of CNS. Contribute to BBB and regulate composition of brain tissue fluid. convert glucose to lactate to feed neurons. secrete nerve growth factor promoting synapse formation.electrical influence on synaptic signaling.
damaged neurons replace by hardened mass of astrocytes
Schwann cells
myelinate fibers of PNS
Nodes of Ranvier
gaps between myelin segments
Initial segment
area before 1st schwann cell and axon hillock form trigger zone where signals begin
neural communication
mechanisms for producing electrical potentials and currents
electrical potential
different concentrations of charged particals in different parts of the cell
electrical current
flow of charged particles from one point to another within the cell
vary in magnitude with stimulus length
get weaker the farther they spread
vary in magnitude with stimulus strength
get weaker the farther they spread
refractory period
period of resistance to stimulation.
absolute refactory period
as long as NA+ gates are open no stimulus will trigger AP
relative refractory period
as long as K+ gates are open only especially strong stimulus will trigger new AP
nerve signal
a chane reaction of sequential opening of voltage gated NA+ channels down entire length of axon
electrical synapses
gap junctions.
chains of 2-40 amino acids. stored in axon terminal as larger secretory granules.act at lower concentrations
excitatory cholinergic
nerve signal opens voltage gated calcium channels in synaptic knob. triggers release of ACh.
Inhibitory GABA-ergic synapse
nerve signal triggers release of GABA which crosses synapse. GABA receptors trigger opening of Cl- channels producing hyperpolarization.
Excitatory adrenergic synapse
acts through 2nd messenger system. receptor is integral membran protein associated with a G protein, which activates adenylate cyclase
which converts ATP to cAMP
modify transmission.raise or lower number of receptors. alter neurotransmitter release synthesis or breakdown
excitatory postsynaptic potentials. a positive voltage change causing postsynaptic cell to be more likely to fire
ihibitory postsynaptic potentials a negative voltage change causing postsynaptic cell to be less likely to fire
Temporal Summation
single synapse receives many EPSP in short time
spatial summation
single synapse receives many EPSP from many cells
presynaptic inhibition
one presynaptic neuron suppresses another.
neural pools
interneurons that share specific body function
diverging circuit
one cell synapses on other that each synapse on others
converging circuit
input from many fibers on one neuron
reverberating circuits
neurons stimulate each other in linear sequence but one cell restimulates the first cell to start the process all over again.
synaptic pontentiation
transmission mechanisms correlate with different forms of memory
long memory. retention of facts as text
long memory. retention of motor skills
molecular changes
long term. tetanic stimulation causes ionic changes.
Alzheimer disease
memory loss for recent events, moody, combative, lose ability to talk, walk and eat
atrophy of gyri
folds in cerebral cortex
tangles and senile plaques
parkinsons disease
progressive loss of motor function beginning in 50s-60s