Term
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Definition
| Said that nervous systems were composed of complex, continuous meshworks of cells and processes in protoplasmic continuity. |
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Term
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Definition
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Term
Glial Cells
amount
3 types |
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Definition
Half the brain volume
10 glial cells per neuron
Schwann cells, oligodendrocytes, astrocytes |
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Term
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Definition
Glia in PNS
Envelops axons and provides sheathing |
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Term
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Definition
Glia in CNS
myelin sheathing of axons |
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Term
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Definition
| Glial cells that wrap capilaries, take up transmitters, supply metabolic substrates, regulate ion concentrations, and aid development |
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Term
| Passive properties of neuron |
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Definition
Resting potential (inside negative)
Injected current causes graded potential with exponential time course as charges accumulate on capacitor
Passive spread is decremental |
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Term
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Definition
t=RC
The time it takes for the voltage change to reach 63% of its final value. Dependends on the resistance and capacitance of a membrane. |
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Term
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Definition
| Determines the value of the membrane potential produced by the conributions of Potassium, Sodium, and Chloride |
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Term
| Absolute refractory period |
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Definition
| Another action potential cannot be generated for at least 1 ms |
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Term
| Relative refractory period |
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Definition
| Action potentials are harder to generate for a few milliseconds. |
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Term
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Definition
Small compared to the length constant, so do not need action potentials.
Graded potentials spread passively |
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Term
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Definition
Very fast,
neruons are connected by connexons at the gap junction
Useful in synchronizing different cells
No moderation |
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Term
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Definition
Unidirectional: presynaptic neuron releases transmitter which binds to postsynaptic receptor
Signal can be modulated (active zone - release proteins, postsynapdic density, proteins that cluster receptors)
Ionotropic or Metabotropic |
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Term
| Ionotropic chemical synapse |
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Definition
Fast
Ligand gated ion channels
for signal transmission
Produce excitatory or inhibitory post synaptic potential |
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Term
| Metabotropic chemical synapses |
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Definition
slow
hormonal effect
For neuronal modulation
GPCR and second messenger cascades are involved. |
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Term
| Function of a chemical synapse |
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Definition
Arrival of action potential opens calcium channels
Calcium triggers vesicle fusion and transmitter release
Neurotransmitter binds to ionotropic or metabotropic receptor |
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Term
| Summation of EPSP and IPSP |
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Definition
Temporal summation: rapidly successive EPSPs summate
Spatial summation: EPSPs from different nerves summate |
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Term
| Difference between CNS and NMJ EPSPs |
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Definition
Neuronal EPSPs are smaller
postsynaptic area, number of receptors, amount of transmitter are all smaller |
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Term
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Definition
result from an increase in permeability to chloride
hyperpolarization
GABA is the main neurotransmitter |
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Term
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Definition
Excitatory
large cleft, large postsynaptic density, round vesicles
glutamate opens sodium/potassium channels |
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Term
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Definition
Inhibitory
narrow cleft, symmetric pre- and post- densities, flat vesicles
GABA or glycine opens chloride channels |
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Term
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Definition
Stimulated by nicotine
blocked by Curare |
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Term
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Definition
found on heart muscle
Stimulated by muscarine
blocked by atropine
More numerous than Nicotinic within CNS |
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Term
| 5 neurotransmitter criteria |
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Definition
-in presynaptic cleft
-released upon stimulation
-mimic effects of presynaptic stimulation when added to extracellular fluid
-There should be a mechanism for removal
-Effect of drugs on transmission must be similar to their effect on experimental application of the neurotransmitter |
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Term
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Definition
| changes in synaptic strength over time |
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Term
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Definition
| amplitude of a postsynaptic potential in response to a presynaptic action potential |
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Term
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Definition
| increase in amplitude of postsynaptic potentials in response to successive presynaptcic impulses |
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Term
| synaptic antifacilitation |
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Definition
| decrease in amplitude of postsynaptic potentials with sucessive presynaptic impulses |
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Term
| facilitaiton and antifacilitation result from.... |
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Definition
| changes in the amount of neurotransmitter liberated per impulse |
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Term
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Definition
| decrease in intensity of a reflex response to a stimulus when the stimulus is presented repeatedly |
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Term
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Definition
| prolonged enhancemnt of a reflex response to a stimulus which results from the presentation of a second stimulus that is novel or noxious. |
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Term
| ionotropic sensory transduction |
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Definition
| the sensory stimulus is received and then tranduced into an electrical signal and both reception and transduction are preformed by the same molecule |
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Term
| metabotropic sensory transduction |
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Definition
| sensory receptor acts like a neurotransmitter or hormone receptor in activating a metabotrobic cascade |
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Term
| specialized photoreceptors |
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Definition
ciliary photoreceptors
rhabdomeric photoreceptors |
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Term
| specialized olfactory organ |
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Definition
| vomeronasal organ - receptor molecules are located in microvilli |
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Term
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Definition
| photoreceptor-containing layer at the back of the eye |
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Term
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Definition
high-acuity region in which intervening cell layers and blood vessels are displaced to the side.
contains tightly packed cones, and not rods. |
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Term
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Definition
more sensitive than cones
used in dim light |
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Term
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Definition
| used in brighter light, for color vision, and for high-acuity vision in animals having a fovea |
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Term
| process of photoreceptor hyperpolarization |
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Definition
-light activated rhodopsin
-activated rhodopsin decreases the concentration of cGMP in cytoplasm
-decrease in cGMP closes nucleotide-gated ion channels
-Sodium influx decreases and cell hyperpolarizes |
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Term
| resting potential of a photoreceptor |
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Definition
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Term
| Visual system: bipolar cells |
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Definition
| receive input from photoreceptors at the outer plexiform layer and synapse on amacrine and ganglion cells in inner plexiform layer |
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Term
| visual system: horizontal cells |
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Definition
| extend tangentially, connecting different regions of the outer plexiform layer |
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Term
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Definition
| mediate similar tangential interconnections in the inner plexiform layer |
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Term
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Definition
output of the retina
axons form the optin nerve |
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Term
| 3 kinds of papillae on the tongue |
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Definition
fungiform (front)
foliate (lateral)
circumvallate (back) |
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Term
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Definition
| 50mM sodium causes inward current through sodium channels |
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Term
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Definition
| H+ modulates Na or K channel permeability |
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Term
| Sweet, Umami, Bitter transduction |
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Definition
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Term
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Definition
| part of the PNS that controls the skeletal musclels |
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Term
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Definition
| part of the PNS that controls autonomic effectors, which includes all neuron-controlled effectors other than striated muscles. |
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Term
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Definition
| concentration of nervous structures and functions at one end of the body |
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Term
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Definition
| carry impulses toward the CNS |
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Term
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Definition
| carry nerve impulses away from the CNS |
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Term
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Definition
| collections of neuronal cell bodies associated with peripheral nerves |
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Term
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Definition
| composed of intermingled neuronal cell bodies, processes, and synaptic contacts |
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Term
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Definition
| tracts of myelinated axons. |
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Term
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Definition
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Term
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Definition
| nerves in the PNS that connect to the brain |
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Term
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Definition
| nerves in the PNS that connect to the spinal cord |
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Term
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Definition
| enlargements of the dorsal roots outside te spinal cord where cell bodies of sensory neurons are located |
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Term
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Definition
| clusters of neuronal cell bodies where peripheral synapses between first and second neurons of sympathetic and parasympathetic difisions are located. |
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Term
| sympathetic nervous system |
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Definition
short
thoracolumbar pregangionic neurons
long adrenergic postganglionic neurons
"fight or flight" |
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Term
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Definition
| releases norepinehprine (noradrenaline) |
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Term
| parasympathetic nervous system |
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Definition
long, craniosacral preganglionic neurons
short cholinergic postgangionic neurons signal muscarinic receptors
"rest and digest" |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| one repeating unit of thick and thin filaments |
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Term
| three factors that affect tension |
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Definition
area
rate (frequency of action potentials)
recruitment (number of actively contracting fibers) |
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Term
| parallel muscle contraction |
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Definition
| forces are additive for the same change in length. |
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Term
| muscle contractions in series |
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Definition
| force for each muscle is the same, but lengths add |
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Term
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Definition
| response to one action potential |
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Term
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Definition
length stays the same, but tension changes.
tension is not enough to move the load |
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Term
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Definition
| tension stays the same, but length changes |
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Term
| two types of skeletal twitch muscle fibers |
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Definition
slow oxidative
fast glycolytic |
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Term
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Definition
| one motor neuron and all the muscle fibers it commands |
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Term
| size principle of muscle contraction |
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Definition
| we recruit smaller motor units first (fewer muscle fibers) |
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Term
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Definition
small,
no t-tubules, sarcomeres, or tropoin
actin-rich |
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Term
| smooth muscle contraction initiated by... |
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Definition
| neurotransmitters, hormones or stretch |
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Term
| single-unit smooth muscle |
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Definition
connected by gap junctions, so depolarization affects all cells and produces a wave of contraction
spontaneous or stretch-activated
modulated by autonomics or hormones |
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Term
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Definition
not stretch-sensitive
neural or hormonal activation
no gap junctions |
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Term
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Definition
sarcomeres
straited
SR
fewer t-tubules than skeletal muscles |
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Term
| Voltage gated sodium channel |
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Definition
six transmembrane segments,
pore loop
voltage sensor
inactivation particle
four domains
Sodium can pass through with one water attached |
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Term
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Definition
six transmembrane subunits
pore loop
voltage sensor
inactivation particle
four separate but identical subunits
highly permeable and highly selective |
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Term
| what affects the rate of pacemaker potentials? |
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Definition
norepinephrine increases rate
acetylcholine decreases rate |
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Term
| steps of vesicle recycling |
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Definition
targeting
docking
priming
fusion
endocytosis (clathrin) |
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Term
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Definition
| protein responsible for the shortening and lengthening of outer hair cells |
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Term
| absorption of light by 11-cis retinal |
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Definition
| produces all-trans retinal, which causes changes in opsin conformation and produces activated rhodopsin |
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Term
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Definition
activated rhodopsin stimulates G protein (transducin)
phosphodiesterase is activated and breaks down cGMP
cGMP-gated sodium channels close
sodium cannot enter cell and hyperpolarization occurs |
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Term
| production of dark current |
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Definition
rhodopsin kinase phosphorylates rhodipsin, which binds to arrestin instead of transducin
GAP promotes GTP hydrolysis causing PDE to dissociate from transducin and is reinhibited by inhibitory subunit
closing of ion channels reduces Ca entry, which disinhibits guanylyl cyclase, allowing more rapid cGMP synthesis |
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