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