Neurophysiology Flashcards
___________is a junction between two neurons
synapse
what generates the axon potential in the presynaptic neuron ?
axon hillock
______-is the same thing as a local potential
graded potential
the synaptic vesicles contain
neurotransmitters
where are the receptors for the neurotransmitters located ?
post-synaptic membrane
calcium influx through the voltage gated calcium channels is important in allowing what ?
vessels to fuse to the membrane and release the neurotransmitter
failure of the influx of calcium at the presynaptic membrane results in
failure of neurotransmitter release
what are the two types of receptors on the POSTsynaptic membrane ?
ionotropic and metabotropic receptors
what are ionotropic receptors
ligand binds, opens the channel and there is a movement of ions down the electrochemical gradient
What are some examples of ionotropic receptors
acetylcholine, glutamate, glycine, and GABA
which type of receptor (ionotropic or metabotropic receptors) have a direct affect on the neurotransmitter ?
ionotropic receptors
what are metabotropic receptors ?
the ligand binds, and activates a G protein and opens a seperate ion channel
what receptor (ionotropic or metabotropic) has a indirect affect on the neutrotransmitter ?
metabotropic
_____________ are examples of metabotropic receptors ?
acetylcholine muscarining and neurepinephrine
What are the three generalized ways neurotransmitters can be removed ?
reuptake into the cell
diffuse away from the synapse
inactivated by enzymes
what happens to choline in a cell ?
it is recycled
what happens to acetate when acetylcholine is cleaved ?
diffuses away
What are the receptors for a EPSP ?
glutamate receptors–AMPA receptors and NMBA receptors
AMPA receptors do what ?
increase sodium permeabilty
what does NMDA do
increases calcium permeability
and IPSP receptors are
glycine and GABA
IPSP cause what to increase in permeability ?
chlorine and potassium
a postsynpatic neuron can be brought to threshold by what two processes
temporal or spatial summation
(t/f) one EPSP can illicit an action potential
NO it is never strong enough!
temporal summation
stimulate A over and over and over again with short amount of time inbetween. second EPSP will add to first and so on!
spatial summation
stimulate A and B resulting in a greater graded potential-action potential
what neurotransmitter is most often associated with being a presynaptic inhibitor
GABA (opens chloride channels)
____________decreases neuron excitability
acidosis
alkalosis increases or decreases neuron excitabilty
increases
what are the two receptors that are know to be inhibitory
glycine and GABA
________is a major excitatory amino acid NT
glutamate
glutamate minds NMDA and
calciun increased and sodium increased
glutamate binds AMPA and
sodium is increased
GABA binds GABA a
chlorine increased
GABA bindds GABAb
potassium increased
glycine causes
increased chlorine
equilibirum potential for sodium
positive 65
equilibirum potential for calcium is
positive 120mv
equilibrium potential for potassium is
-85 mv
equilibrium potential for chlorine is
-85mv
preganglionic neurons in the CNS are
myelinated
postganglionic neurons in the CNS are
ummyelinated
oculomotor innervates
ciliary and sphincter pupillae
facial nerve innervates
sublingual, submandibular, and lacrimal gland
glossopharyngeal nerve innervates
parotid gland
vagus nerve innervates
stomach, heart, pancreas, small intestine, bronchioles and part of the large intestine and the pancreas
what are the cells called of the adrenal medualla
chromaffin cells
the chromaffin cells are innervated by
preganglionic sypmathetic fibers
how much epinephrine is secreted by the chromaffin cells
80% the rest is 20%
adrenergic neurons release _________ as the NT
NE
cholinergic neurons release
acetylcholine
parasympathetic preganglionic NT and receptor
acetylcholine nicotinic
parasympathetic postganglionic NT and receptor
actylchloline muscarinic receptor
sympathetic preganglionic
acteylcholine and nicotinic receptors
sympathetic postganglionic
NE alpha1,2 and beta 1,2 receptors
adrenal gland preganglionic sympathetics
acetylcholine, nicotinic
somatic nervous system axons
acetylcholine, nicotinic
alpha 1 is found
vascular smooth muscle of skin, GI bladder sphincters, and radial muscle of iris
alpha 2 is found
GI tract
beta 1 is found
heart
alpha 1 is
excitatory
alpha 2 is
inhibitory (relaxation and dilation)
beta 1 is
excitatory
beta 2 receptors are found
on vascular smooth muscle of skeletal muscle, broncioal smooth muscle and walls of GI tract and bladder
beta 2 are
relaxatory
_________are located on the autonomic ganglia of the sympathetic and parasympathetic nervous systems and at the neuromuscular junctions
nicotinic
nicotinic receptors are
excitatory
__________are found in the heart, smooth muscle and glands
muscarinic
_________are excitatory to smooth msucle and glands (increased gI motility increased secretion) parasympathetic
muscarinic
action of beta 1 on the heart
increased heart rate, contractility and Av node contraction
action of alpha 1 on blood vessels
constricts
action of beta 2 on blood vessels
dilates
alpha 2 and beta 2 do what ot GI tract
decreased motility
alpha 1 at GI
constricts sphincters
beta 2 at the bladder
relaxes bladder
alpha 1 at the bladder
constricts sphincter
what receptors are at the sweat glands
sympathetic cholinergic
sympathetics cause increased or decreased sweating
sweating
alpha 1 at the eye
dilates pupil
___________is secreted by all preganglionic neurons
acetylcholine
what is released from parasympathetic postganglionic neurons
acetylcholine
what is released from sympathetic postganglionic neurons that innervated sweat glands
acetylcholine
what type of fibers is NE secreted by
adrenergic
NE is found at
sympathetic postganglionic neurons and at the adrenal medulla
nictonic receptors are found
autonomic ganglia, neuromuscular junction and adrenal medulla
muscarninc receptors are found
cardiac muscle, smooth muscle and glands
sweat glands innervated by ____ type of receptors
muscarininc from preganglionic parasympathetic
alpha 1 is
excitatory
alpha 2
inhibitory
beta 1
excitatory
beta 2
relaxation
what receptor is responsible for dialation of bronchioles in the lung
beta 2 adrenergic
what receptro is responsible for vasoconstriction in the viscera and skin
alpah 1 adrenergic
enzymes that break down NE
monoamine oxidase and catechol-o-methyltransferase
catechol-methyltransferse is found in the
postsynpatic cell
MAO is found in
presynaptic cell
two mechanisms for epinephrine termination
COMT or diffuses away
beta 1 in the heart sympathetic effect
increases HR and contractility
muscarininc in heart
decreased HR and contractility
alpha 1 in skin
vasoconstriction
beta 2 in bronchioles
bronchodilation
muscarinic in bronchioles
bronchoconstriction
alpha 1 internal anal sphincter
contraction
muscarning internal anal sphincter
relazation
beta 2 GI wall
relaxed
muscarinic GI wall
contraction
sweat glands
muscarninc
alpha 1
dialator pupillae
muscarinic
sphincter pupillae
what organs are typically without dual innervation
adrenal medulla, sweat glands and MOST BLOOD VESSELS
aortic arch innervated by
vagus nerve
carotid sinus innervated by
glossopharyngeal n
_________controlls BP, heart rate, respiration and swallowing
medulla oblongata
___________controls micturition and secondary controller of respiation
pons
_________controls sympathetic and parasympathetic nervous systems
hypothalamus
what is the action of botox
blocks acetylcholine release
organophosphates and sarin block
acetylcholinesterase (Ach termination enzyme)
___is an antagonist to acetylcholine muscarinic receptors
atropine