-
_________ form myelin sheath around peripheral axons in the PNS
Schwann cells
-
___________ support sensory and autonomic ganglia ( ganglia=PNS)
satellite cells
-
________ form myelin sheath around CNS axons
oligodendrocytes
-
________ help regulate the external environment of neurons (CNS)
astrocytes
-
________ line the ventricles in the brain and the spinal cord (CNS)
ependymal cells
-
________ travel the CNS and "eat" foreign and degenerated materials
microglia
-
some axons in the CNS and PNS are surrounded by ________, which is a fatty layer of insulation
myelin sheath
-
Successive wrapping of Schwann cells around axons in the ____ produces myelin sheath.
PNS
-
exposed gaps of myelin sheath used to produce nerve impulses are named nodes of __________
Ranvier
-
Oligodendrocytes use octopus-like extentions to create _________ around multiple axons in the _____. (AKA white matter)
-
The ________ is defined by its tight junction selective molecule diffusion, requiring specific transport methods through the capillaries into the brain.
Blood brain barrier
-
The _____________ is significant in preventing drug treatment of degenerative disorders (i.e. Parkinson's). Certain chemicals do not diffuse into the brain properly.
blood brain barrier
-
pseudounipolar neurons have one process that splits ('T' shaped). They are _________ neurons
Sensory
-
sensory neurons are ________polar neurons
pseudouni(polar)
-
Bipolar neurons have (2) processes, such as in the retina and cochlea (bow-tie shaped). They are ________ neurons
sensory
-
neurons with (2) processes are ________polar neurons
bi(polar)
-
Multipolar neurons have many dendrites but one axon. They are 1: _______ 2: __________ neurons
-
Schwann cells "eat" cut(damaged) axons, form a tube, and then a new axon tip grows to fill it out. This is ________, and it occurs in the ___.
-
myelination = ________ color; non-myelinated axons = ________ color
-
L-Dopa is permeable to the ____________ but dopamine is not (Parkinson's).
blood brain barrier
-
Step (1) of action potential: ___+ gates open and the __+ diffuses into the cell (starting depolarization)
Na+
-
Step (2) of action potential: ___+ gates open and the __+ diffuses out of the cell (while continuing to depolarize)
K+
-
resting potential is __ mV
-70mV
-
Threshold (potential) is at __ mV
-30 mV
-
action potential is at __ mV
+30 mV
-
Hyperpolarization is at __ mV
-90 mV
-
Na+ gates are deactived at _______ potential
action potential (to begin repolarization)
-
depolarization is caused by _____________ into the axon
diffusion of Na+ in
-
repolarization is caused by _____________ out of the axon
diffusion of K+ out
-
conduction in _________ axons: every surface of axon membrane can produce an action potential
unmyelinated
-
saltatory ("leaping") conduction happens in _________ axons
myelinated
-
myelination increases OR decreases action potential conduction?
increases (due to fewer necessary conduction sites and less "leaking" of charge.)
-
a stimulus causes positive charges to flow into a cell; this is called __________
depolarization
-
a return to resting membrane potential is called _________
repolarization
-
Axon resting potential: Permiability ratio of Na+ (out) to K+ (in) is __:__
3:2 -- 3 Na+ out: 2 K+ in
-
Na and K gating allows for action potentials because each gate opens at a different _________
voltage (mV)
-
once an axon is depolarized to threshold, it will fire. this is the _________________ law
all-or-none law
-
increased stimulus strength = __________ action potential frequency
increased
-
the manditory minimum interval between action potentials is called a _______________ (regulates frequency)
refractory period
-
gap junctions are found in ____________ synapses
electrical
-
__________ synapses are when pre and postsynaptic neurons are separated by a synaptic cleft
chemical
-
cardiac muscle is an example of ___________ synapses (gap junctions)
electrical
-
Na+ or Ca+ entering a (post-synaptic) neuron causing graded depolarization for it to become less negative is ___________
EPSP-- excitatory post synaptic potential
-
Cl- entering a (post-synaptic) neuron causes graded polarization, making it more negative is ___________
IPSP-- Inhibitory post synaptic potential
-
______ junctions are joined in areas of contact with low electrical resistance. this allows for uniform action potentials in the ____ muscles
-
______________ are little bubbles of neurotransmitters in the axon terminal that dock with SNARE and released by exocytosis (into the cleft)
synaptic vesicles
-
action potentials stimulate the entry of __+ into the axon terminal of the pre-synaptic neuron, prompting vesicles to undergo exocytosis into the cleft
Ca+
-
NT release: 1-action potential, 2- ___+ channels open, 3- __+ binds (to protein) 4- __+ protein complex stimulates fusion and exocytosis
Ca+
-
_________ gated/regulated ion channels require input from something like Ca+ (found in post-synaptic membrane)
chemical
-
_________ gated/regulated ion channels require input from something like a +30 mV charge (found in axon)
voltage
-
While NT binding receptors are specific, certain "toxins" may also activate these receptors. ACh's stimulatory effects (muscle contractions) may be activated by __________
nicotine (@ the nicotinic receptors)
-
ACh binds to muscarinic receptors in the heart cells, causing ___-protein to open K+ outward diffusion, which means ____ heart rate (K+ out = polarization/inhibition)
- G-proteins;
- slower heart rate
-
The enzyme ___________ deactivates free ACh at the post-synaptic cell membrane after it "does its job" to prevent further activations (No deactivation = spastic paralysis in muscle; principle of nerve gas)
AChE (acetylcholinesterase)
-
Alzheimer's disease is associated with the loss of ___________ neurons, which use ACh as a NT (Tx = AChE inhibitors)
Cholinergic
-
_________ are regulatory molecules derived from amino acids. They are also NT's ( i.e. dopamine, norepinephrine, epinephrine).
monoamines
-
monoamine NT's at the synapse are stopped by (1):_________ from the cleft into the presynaptic Neuron, then (2): __________ of the monoamine by an enzyme MAO (monoamine oxidase)
-
two pathways of dopamine NT use in the brain are 1: ______ control, & 2: __________
- motor control; (nigrostriatal)
- emotional reward (mesolimbic)
-
MAO inhibitors prevent reuptake of monoamines, which plays a role in treatment for __________
depression, Parkinson's
-
cocaine ___________ reuptake of dopamine
prevents
-
SSRI's prevent reuptake of __________
5-HT (serotonin)
-
_________ are inhibitory motor NT's: they hyperpolarize the post-synaptic neuron rather than depolarizing (Opens Cl- channels rather than Ca+)
Glycine & GABA
-
Huntington's disease is defined as a loss of motor control. This is because of a deficiency in inhibitory motor NT _____.
GABA
-
Example categories of _________: Amines, amino acids, lipids, gases (Nitric oxide etc) Purines(ATP)
Neurotransmitters
-
___________ is the major excitatory NT in the brain (80% of all)
glutamate
-
NMDA receptors are involved in ____________ storage
memory
-
Benzodiazepines are _________ agonists, regulating anxiety.
GABA
-
"runner's high" may be influenced by exogenous ________
opiods
-
_________ acts as a blood vessel dialator. involved in Viagra
NO (nitric oxide)
-
____________ summation is the result of many pre-synaptic neurons converging on the dendrites of a neuron
Spatial
-
__________ summation is successive NT release, resulting in the summation of EPSPs in the post-synaptic neuron.
Temporal
-
Synaptic potential OR action potential: which does NOT have a refractory period?
Synaptic potential
-
the improved ability of a presynaptic neuron that has been stimulated at a high frequency to then stimulate the post-synaptic neuron over a long period of time is __________ (method of neural learning?)
Long-term potentiation (LTP)
-
a process where endocannabinoids suppress the release of NT from pre-synaptic neurons. this happens over a long period and inhibits functioning for some time _________
Long-term depression
-
_______________ inhibition: the amount of NT released at the end of the pre-synaptic neuron is decreased by a second neuron's signal
presynaptic
-
_______________ inhibition: induces hyperpolarization in a post-synaptic neuron
postsynaptic
|
|