Chapter 11c Flashcards
what are the 2 types of postsynaptic potentials?
EPSP- excitatory postsynaptic potentials
IPSP- inhibitory postsynaptic potentials
what allows chemically gated channels to open and the flow of Na+ and K+ in opposite directions?
neurotransmitter binding
___(1)___ influx is greater than ___(2)___ efflux
(1) Na+
(2) K+
net depolarization from Na+ influx and K+ efflux is called what?
EPSP
EPSP helps trigger action potential only if what happens?
if EPSP is of threshold strength
once EPSP is of threshold strength, what happens?
spreads to axon hillock
trigger opening of voltage-gated channels
AP generated
which postsynaptic potential causes a local depolarization of the postsynaptic membrane, which brings neuron closer to AP threshold?
EPSP
which postsynaptic potential hyperpolarizes and makes it more difficult for action potential to generate?
IPSP
IPSP makes the membrane more permeable to which ions?
K+ and Cl-
EPSPs can ______ to influence postsynaptic neuron.
summate
which postsynaptic potentials can summate?
both EPSPs and IPSPs
one or more presynaptic neurons transmit impulses in rapid fire order is called what?
temporal summation
postsynaptic neuron stimulated simultaneously by large number of terminals at the same time is called what?
spatial summation
when IPSP summates with EPSPs they ______ ______.
cancel out
repeated use of synapse increases the ability of the presynaptic cell to what?
excite postsynaptic neuron
when postsynaptic neuron is excited, the Ca2+ concentration does what?
increases in presynaptic terminal and postsynaptic neuron
what type of stimulation partially depolarizes postsynaptic neurons?
brief high-frequency stimulation
which channels (receptors) allow Ca2+ entry?
chemically gated channels (NMDA receptors)
what promotes more effective responses to subsequent stimuli?
kinase enzymes activated by Ca2+
a lot of AP causes what?
large graded potential that goes above threshold
the postsynaptic neuron decides what?
if threshold is reached for AP
what triggers muscle contractions and turns on genes that strengthen synapse?
Ca2+
when excitatory neurotransmitter is released by 1 neuron but inhibited by another via axoaxonic synapse is called what?
integration (presynaptic inhibition)
less neurotransmitter is release during what?
integration
integration forms smaller ______.
EPSPs
what is the language of the nervous system?
neurotransmitters
most neurons make what? exert what?
make: 2 or more neurotransmitters
exert: several influences
what is usually release at different stimulation frequencies?
neurons
neurons are classified by ______ ______ and by ______.
chemical structure and function
which neurotransmitter is released at neuromuscular junctions, some ANS neurons, and some CNS neurons?
acetylcholine
which neurotransmitter is synthesized from acetate and choline by enzyme choline acetyltransferase?
acetylcholine
acetylcholine is degraded by which enzyme?
acetylcholinesterase (AChE)
what are the 2 biogenic amines?
catecholamines and indolamines
which biogenic amine is this?
dopamine, norepinephrine, and epinephrine
synthesized from amino acid tyrosine
catecholamines
which biogenic amine is this?
serotonin and histamine
synthesized from tryptophan and histidine
indolamine
dopamine
controls mood
norepinephrine and epinephrine
autonomic, sympathetic response
fight or flight
histamine
inflammation
serotonin is synthesized from which amino acid?
histamine is synthesized from which amino acid?
serotonin: tryptophan
histamine: histidine
amino acids involved as neurotransmitters
glutamate
aspartate
glycine
GABA
what are the 3 neuropeptides?
substance P
endorphins
gut-brain peptides
substance P
mediator of pain signals
endorphins
reduce pain perception
natural opiates
gut-brain peptides
stimulate release of enzyme and bile
digestion
purines involved as neurotransmitters
ATP and adenosine
what is a potent inhibitor in the brain?
adenosine
purines are usually ______.
inhibitory
caffeine blocks which receptors?
adenosine receptors
what acts both in the CNS and PNS and can produce fast or slow responses?
purines
purines induce Ca2+ influx in ______.
astrocytes
what are some gasotransmitters (gases and lipids)?
nitric oxide (NO) carbon monoxide (CO) hydrogen sulfide gases (H2S)
what do gasotransmitters bind in the brain?
bind with G protein-coupled receptors
which neurotransmitters are lipid soluble and synthesize on demand?
gasotransmitters and endocannabinoids
nitric oxide (NO)
learning memories smooth muscle relaxation in intestine (digestion) brain damage in stroke patients lowers blood pressure
hydrogen sulfide gases
act directly on ion channels to alter function
endocannabinoids are involved in what functions?
learning
memory
hunger (control appetite/suppress nausea)
affect immune system
which neurotransmitters act at same receptors as THC?
endocannabinoids
what are the most common G protein-linked receptors in brain?
receptors of endocannabinoids
neurotransmitters are classified by which functions?
effects (excitatory vs. inhibitory)
actions (direct vs. indirect)
effect determined by receptor to which it binds:
GABA and glycine?
glutamate?
ACh?
GABA and glycine: inhibitory
glutamate: excitatory
ACh: excitatory at neuromuscular junctions in skeletal muscle and inhibitory in cardiac muscle
sometimes the ___(1)___ neurotransmitter has a different response because acts on ___(2)___ receptor.
(1) same
(2) different
neurotransmitter binds to/opens ion channels and promotes rapid responses by altering membrane potential is what type of action?
direct action
examples of direct action
ACh
amino acids
neurotransmitter acts through intracellular second messengers (G protein pathways) and have broader longer-lasting effects similar to hormones is what type of action?
indirect action
examples of indirect action
biogenic amines
neuropeptides
dissolved gases
which receptors mediate fast synaptic transmission?
channel-linked receptors
which receptors oversee slow synaptic responses?
G protein-linked receptors
channel-linked (ionotropic) receptors action is ______ and ______
immediate and brief
what are channels for small cations in channel-linked receptors?
excitatory receptors
what receptors allow Cl- influx?
inhibitory receptors
Cl- influx causes ______
hyper polarization
what are G-protein linked (metabotropic) receptor responses like?
indirect, complex, slow, prolonged
which receptor causes widespread metabolic changes?
G protein-linked receptors
which receptors bind biogenic amines and neuropeptides and are examples of G protein-linked receptors?
muscarinic ACh receptors
what is the mechanism of action for G protein-linked receptors?
- neurotransmitter binds G protein-linked receptor
- G protein activated
- control production of 2nd messengers
what opens/closes ion channels, activates kinase enzymes, phosphorylates channel proteins, activates genes and induces protein synthesis?
second messengers
______ function in groups.
neurons
what do the functional groups of neurons do?
integrate incoming info and then forward it to other places
single presynaptic fiber branches and synapses with several neurons in pool are called ______.
simple neuronal pool
discharge zone
neurons closely associated with incoming fiber
respond quickly
facilitated zone
neurons farther away from incoming fiber
not activated unless very strong signal present
patterns of synaptic connections in neuronal pools are called ______.
circuits
4 types of circuits
- diverging
- converging
- reverberating
- parallel after-discharge
1 input, many outputs
ex) single neuron > activate motor neurons > control muscle
diverging circuit
many outputs, 1 input
ex) different sensory stimuli elicit same memory
converging circuit
signal travels through chain of neurons, each feeding back to previous neurons (feedback loops)
ex) breathing, sleep wake cycle, repetitive motor activities
reverberating circuit
signal stimulates neurons arranged in parallel arrays that converge on single output cell
ex) solving math problems
parallel after-discharge circuit
serial processing
reflex
receptor, sensory neuron, CNS integration center, motor. neuron, and effector are 5 components of pathways called ______.
reflex arcs
parallel processing
higher level mental functioning
1 stimulus promotes several responses
example of parallel processing
a sensed smell reminds of an odor and associated experiences
growth cone at tip of axon interacts with environment via what?
cell surface adhesion proteins
neurotropins
nerve growth factor (NGF)
cell death
if do not form synapse with target
apoptosis during development