Term
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Definition
Simplest
diffuse arrangement of neurons
ex. cnidarians |
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Term
Ventral, solid nerve cord,
ganglia & a "brain" |
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Definition
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Term
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Definition
| Clusters of nerve cell bodies |
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Term
Brain & dorsal, hollow spinal cord (CNS)
and nerves (PNS) |
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Definition
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Term
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Definition
*functional units of nervous system
*transmit electrical impulses
*4 regions- cell body, dendrites, axons, axon terminals. |
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Term
| Direction of impulse conduction |
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Definition
| dentrite > cellbody > axon |
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Term
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Definition
| Enlarged area of neuron containing most of cytoplasm, nucleus & most other organelles. |
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Term
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Definition
| highly branched process that receive information from sensory receptors or other neurons. Transmit information to cell body. |
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Term
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Definition
| Single process that transmits information away from the cell body |
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Term
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Definition
| swelling at tip of axon; synapse with target cell (another neuron, muscle or gland cell) |
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Term
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Definition
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Term
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Definition
| rare; found only in eye and ear |
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Term
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Definition
| motor neurons & interneurons |
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Term
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Definition
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Term
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Definition
(lipid) sheaths provide electrical insulation of neurons.
*Myelinated neurons can conduct impulses faster than non-myelinated neurons |
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Term
| GLIAL CELLS (SUPPORT CELLS) |
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Definition
*do not transmit electrical signals
*are 15-20 times more numerous than neurons
3 TYPES=
-Astrocytes
-Oligodendrocytes
-Schwann cells |
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Term
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Definition
| Star shaped cells in CNS that form the blood-brain barrier |
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Term
OLIGODENDROCYTES
(glial cell) |
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Definition
| Form myelin sheaths around axons in the CNS |
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Term
SCHWANN CELLS
(glial cell) |
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Definition
| form myelin sheaths around axons in the PNS |
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Term
NON-TRANSMITTING (resting) NEURON
(conditions) |
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Definition
*resting potential is a (-) number
* Na+, Cl- & Ca2+ (^ concentration outside neuron)
* K+ (^ concentration inside neuron) |
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Term
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Definition
*requires ATP
*Pumps 3 (Na+)out for every 2 (K+) in |
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Term
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Definition
* proteins that permit movement of ions accross membrane
*are selective to (Na,K,Cl,&Ca)
*may be gated or ungated(always open)
*(K+)- most common ungated channel in resting neuron |
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Term
SODIUM-POTASSIUM DIFFUSION
(resting) |
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Definition
Sodium-inward
potassium-outward
*P.M. is 100 times more permeable to potassium than sodium (resting) |
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Term
GATED ION CHANNELS
(3 types) |
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Definition
*Mechanically gated
*Chemically gated
*Voltage gated |
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Term
| MECHANICALLY GATED ION CHANNELS |
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Definition
| open or close when membrane is deformed |
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Term
| CHEMICALLY GATED ION CHANNELS |
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Definition
| open or close in response to a specific chemical |
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Term
| VOLTAGE GATED ION CHANNELS |
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Definition
| open or close in response to changes in membrane potential |
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Term
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Definition
Local changes in membrane potential; vary in magnitude depending on stimulus strength.
-local flow decays |
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Term
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Definition
opens voltage-gated ion channels; (Na+) enters & the membrane potential becomes less negative (closer to zero)
(EXCITATORY) |
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Term
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Definition
| opens voltage-gated (K+) channels; potassium exit & membrane potential becomes more negative (less than -60mV). (INHABITORY) |
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Term
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Definition
| -larger the stimulus the greater the change in M.P. |
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Term
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Definition
| -closed unless stimulated to open by some type of stimulus. |
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Term
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Definition
| most common on axons; less so on dendrites & cell bodies. |
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Term
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Definition
| action potential jumps from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane. |
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Term
| SPEED OF ACTION POTENTIAL AFFECTED BY: |
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Definition
*diameter of axon
*myelination |
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Term
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Definition
| junction between two neurons or between a neuron and an effector. |
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Term
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Definition
| conducts impulses TOWARD the synapse. |
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Term
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Definition
| conducts impulses away from the synapse. |
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Term
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Definition
(contain gap junctions)
*ions flow DIRECTLY from presynaptic cell to postsynaptic cell. |
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Term
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Definition
*convert electrical signals to chemical signals
*presynaptic neuron RELEASES chemical NEUROTRANSMITTER.
*postsynaptic cell membrane has receptors for neurotransmitters
*(most common synapses) |
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Term
| NEUROTRANSMITTERS ARE RELEASED BY... |
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Definition
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Term
| ARRIVAL OF ACTION POTENTIAL TRIGGERS... |
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Definition
| opening of voltage-gated SODIUM channels |
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Term
| 2 TYPES OF RESPONSES IN POSTSYNAPTIC NEURONS |
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Definition
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Term
EPSPs
(postsynaptic neuron responses) |
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Definition
-(Excitatory PostSynaptic Potentials)
*depolarization occurs |
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Term
IPSPs
(postsynaptic neuron responses) |
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Definition
-(Inhabitory PostSynaptic Potentials)
*Hyperpolarization occurs |
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Term
| NEURON GENERATES ACTION POTENTIAL ONLY IF... |
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Definition
| SUM of EPSPs & IPSPs surpass the threshold. |
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Term
| SUMMATION TAKES PLACE IN THE... |
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Definition
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Term
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Definition
| several ESPSs (or IPSPs) delivered at different sites arrive at axon hillock simultaneously |
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Term
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Definition
| rapid, repeated ESPSs (or IPSPs) delivered at a single site arrive at axon hillock. |
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Term
| TYPES OF NEUROTRANSMITTERS (NT) |
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Definition
*Acetylcholine
*Amino Acids
*Monoamines
*Peptides
*Gases |
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Term
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Definition
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Term
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Definition
*Glutimate- most common excitatory NT in CNS
*GABA- Common inhibitory NT (CNS) |
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Term
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Definition
*Dopamine-CNS; loss of dopamine neurons causes Parkinson's disease.
*Serotonin-CNS; mood enhancer; involved in sleep/wake cycles. |
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Term
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Definition
*Endorphines- decrease perception of pain (morphine, heroin, opium & codine mimic endorphins; attach to endorphin receptors).
*Substance P- Released by neurons sensitive to heat and pain |
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Term
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Definition
*Nitric oxide (NO)
*Carbon Monoxide (CO) |
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Term
NICOTINIC RECEPTORS
(acetylcholine receptor) |
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Definition
*ionotropic
*Excitatory
-Ach up |
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