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A&P II - Neurophysio

A&P I - Human Neurophysiology

QuestionAnswer
all neurons are ______________ and respond to stimuli excitable
stimuli generates ____________________ __________________ across neuron plasma membrane electrical changes
what are the two forms of electrical changes in neurons local (graded) potentials and action potentials
membrane potential is synonymous with what term resting potential
this potential is temporary, localized change in resting potential graded potential
this potential is an electrical impulse, produced by graded potential, and propagates along surface of axon to synapse action potential
Describe synaptic activity the release of neurotransmitters at presynaptic membrane which produces a graded potential in post synaptic membrane
what is information processing integration of stimuli ( response) of postsynaptic cell
_______________ is the measure of potential energy generated by separated charge voltage
voltage is always measured between ____________ point(s) and it is called - ___________________ or portential 2 points; potential difference
the greater the difference between the 2 points the (higher/lower) the voltage higher
_______________ is the flow of electrical charge between two points current
the flow of electical charges (current) can be used to perform ________________ work
_________________ is a material's opposition to the flow of electric current resistance
___________________ is a substance with high electrical resistance insulator
a ________________________ is a substance with low electrical resistance conductor
what is the general charge of the human body neutral (same number of positive and negative charges)
(same/opposite) charges attract opposite
__________________________ is required to separated opposite charges across a membrane energy
in the physics current reflects the flow of _________________; but in the human body current is reflected by the flow of _________________ electrons (physics); ions (human body)
there is a potential on either side of membranes when : _______________________________ and _________________________________ number of ions is different across the membrane; membrane provides a resistance to ion flow
ion channels are __________________ membrane protiens
how do membrane proteins allow ions into/out of a cell they change shape to open/close the channel
__________________________ channels are always open passive/leakage/non-gated
_______________________ - gated channels open with binding of specific chemical (neurotransmitter in case of the nervous tissue) chemically/ligand - gated channels
________________________ channels open and close in response to membrane potential voltage -gated
________________________ channels open and close in response to physical deformation of receptors mechanically gated
what is the voltage of resting membrane potential -70mV
the membrane of a cell is polarized because there is a potential voltage difference (of -70mV) across the membrane of a resting neuron
what does the minus sign on the -70mV signify on the membrane potential the inside of the membrane is negatively charged
the inside of the membrane is (negatively/positively) charged and the outside of the membrane is (negatively/positively) charged inside = negative; outside = positive
resting membrane potential (exists only across the membrance/in the entire cell) RMP exists only across the membrane potential; generally most of the solution in the cell are neutral
describe the membrane permeability to protien anions, sodium cations, potassium cations, and chloride ions. Protien anions = impermiable, Na+ = Slightly permeable, K+ = 75X more permeable than Na+, Cl- = freely permeable
why is there no equilibrium in the ion concentration of ECF and ICF ATP-driven sodium/potassium pump
in the sodium/potassium ion pump, (2/3) sodium are (ejected/imported) to the cell while (2/3) potassium ions are (ejected/imported) the the cell 3 sodium ejected; 2 potassium imported
what three major events cause the membrane potential to change in a cell depolarization, repolarization, and hyperpolarization
during depolarization; the membrane potential becomes (more/less) negative than resting membrane potential less
what happens during repolarization the membrane returns to its membrane potential
during hyperpolarization the membrane potential becomes (more/less) negative than resting membrane potential more
Membrane potential changes are produced by: ______________________ and _________________________ membrane permeability changes to ions, alterations of ion concentrations across the membrane
name the two types of membrane signals graded potentials and action potentials
___________________ potentials are incoming signals over short distances; while _____________________ potentials are over a long distance graded potentials (short); action potentials (long)
graded potential, occurs on a small area of the neuron membrane and depolarizes by _____________________ graded potential depolarizes by a stimulus
name the four steps of graded potential depolarization 1) Na+ channels open, 2) Na+ ions enter cell, 3) Membrane potential rises, and 4) depolarization occurs
during graded potential flow only occurs on (one/both) sides of the membrane potential occurs on both sides of the membrane
during graded potentials, most of the charge is lost through __________________________ most of the charge is lost through leak channels
graded potential is _____________________ decremental
define decremental dies with increasing distance
where on the neuron does localized changes (graded potential) usually occur dentrites
define the term graded the magnitude of response is proportional to the stiumlus
graded potential are decremental, which means the intensity the intensity decreases with distance
the ____________________ of a graded potential varies directly with the strength of the stimulus magnitude
with graded potential, the stronger the stimulus, the more _______________ changes and the _________________ the current flows stronger stimuli, more voltage change, farther flow
what type of graded potential can initiate action potential a graded potential that is sufficiently strong enough can start an action potential
a subthreshold stimulus is a week local depolarization that does not reach threshold
a threshold stimulus is a stimulus that is strong enough to push the membrane potential toward and beyond the axon hillock
the (action/graded) potential is an all-or-none phenomenon action potential is an all or none phenomenon
this concept about action potential describes the aspect that action potential either happen completely or do not happen at all all or none phenomenon
when does depolarization become self-generating when the potential reaches threshold
during depolarization, the Na+ permeability is ____________________ times higher than a resting cell 1000
at the end of depolarization the internal charge is now (positive/negative) and the actual numerical charge is ______________ mV positive; +30mV
subthreshold depolarization (will/will not) results in an action potential subthreshold WILL NOT results in action potential
action potential begins when (chemically/voltage)-gated NA+ channels open at the trigger zone action potential begins when VOLTAGE-gated Na+ channels open
a graded potential becomes an action potential at ___________ trigger zone/axon hillock
the amplitude of action potential is _________ mV 100 mV
action potentials (do/do not) decrease in strength over distance Action potentials DO NOT decrease in strength
because it does not decrease in strength over distances, ____________________ are great mechanisms for sending signals over long distances action potentials are ideal mechanisms for sending signals over long distances
the action potential in the axon of a neuron is called a nerve impules
during resting states voltage-gated Na+ and voltage-gated K+ channels are (open/closed) during resting states voltage-gated Na+ and voltage-gated K+ channels are CLOSED
during resting state leak channels (passive) are open which allows for small movements of Na+ and K+ between ECF and ICF
activation gates (voltage-gated Na+ channels) are (fast/slow); during resting state they are (open/closed) and respond to depolarization by (opening/closing) fast; closed; opening
inactivation gates (voltage-gated Na+ channels) are (fast/slow); during resting state they are (open/closed) and during depolarization the channel is (opened/closed) slow; open; closed (or blocked during depolarization)
during depolarization the channel opens and then ___________________ Na+ channels deactivates (it's blocked)
name the three states of a voltage-gated Na+ channel 1) inactivation gate open, and activation gate closed, 2) activation gate and inactivation gate is open, 3) activation gate is open but inactivation gate is closed
name the two states of voltage-gated K+ channels activation gate closed and activation gate open
local/graded potential uses (chemically/voltage)-gated Na+ channels to depolarize a cell graded potential uses chemically-gated Na+ channels
as membrane potential goes from -70 mV to -55 mV (threshold) what gates are open from -70 mV to -55 mV chemically-gated Na+ channels
at threshold (-55 mV) what gates open at threshold voltage-gated Na+ channels activate and gate opens until membrane potential becomes +30 mV
at +30mV, what is the gated activity voltage-gated Na+ channels inactivate and voltage-gated K+ channels open and K+ leaves the ICF
the depolarization of an axon is an example of a (positive/negative) feedback system positive feedback system
at what voltage point do voltage-gated Na+ channels open on an axon -55mV (at threshold stimulus)
what major event occurs when voltage-gated Na+ channels open Na+ diffused into the cell
what major action(s) occur during repolarization voltage-gated Na+ channels become inactive and the voltage-gated K+ channels open
at what voltage-point does voltage-gated K+ channels open +30 mV
what major event occurs when voltage-gated K+ channels open K+ rushes out of the neuron
slower voltage-gated K+ channels stay open and cause _________________________ with a voltage of -90mV hyperpolarization
when repolarization occurs the resting ionic conditions (have/have not) been returned back to normal HAVE NOT, repolarization restores the resting electrical conditions of the neuron, however the resting ionic conditions are not restored
ionic redistribution of an axon after repolarization is brought back to resting conditions by ________________________ sodium-potassium pump
________________________ is the time period from beginning of action potential to return to resting state refractory period
during the absolute refractory period, the membrane (will/will not) respond to additional stimuli absolute refractory period will not respond to additional stimuli
describe the state of the voltage-gated Na+ channels during absolute refractory periods voltage gated Na+ channels are either open or inactivated
describe the membrane potential during the relative refractory period the membrane potential is almost normal
what type of stimulus is needed to initiate another action potential during the relative refractory period very large stimulus
what are the three purposes of the absolute refractory period 1) prevent neuron from generating action potential, 2) ensures that each action potential is separate, 3) enforces one-way transmission of nerve impulses
describe the voltage-gated channels during the relative refractory period. what phase or action potential is the axon in during the relative refractory period voltage gated Na+ channels are closed, voltage-gated K+ channels are open, and the action potential is in repolarization
name the two different types of action potential propagations continuous propagation and saltatory propagation
the action potential in unmyelinated axons are (continuous/saltatory); while the action potential in myelinated is (continuous/saltatory) continuous = unmyelinated; saltatory = myelinated
conduction velocities (vary widely/are the same) among all neural axons conduction velocities VARY WIDELY among all neural axons
what are the two factors that effect the rate of propagation 1) presence of a myelin sheath, 2) axon diameter
the presence of a myelin sheath (increases/decreases) the impulse speed presence of a myelin sheath increases the speed of an impulse
the (larger/smaller) the diameter of an axon, the faster the impulse larger the diameter
in (saltatory/continuous) conduction the current passes though a myelinated axon only at the nodes of ranvier SALTATORY conduction passes though a myelinated axon at the nodes of ranvier
in saltatory conduction, voltage-gated Na+ channels are concentrated at ______________________ the nodes of ranvier
in this conduction type, the action potentials are triggered only at the nodes of ranvier and "jump" from one node to the next saltatory action, action potential jumps from one node to another
ion movement is related to cytoplasm _______________________ concentrations
increased axon diameter, the (higher/lower) the resistance lower resistance
Axons are classified into 3 groups (A, B, and C), describe Type A axons they are the larges axons and are highly myelinated. They can reach speeds of up to 150 m/s (or 300 mph)
what type of information does Type A axons carry to the CNS information about balance, position, touch, and pressure sensations
motor neurons that control skeletal muscle movement are type ______________ fibers motor neurons that control skeletal muscle are TYPE A fibers
what type division of the nervous system is controlled by Type B and C fibers autonomic Nervous system
Type ____________ fibers are smaller myelinated and have an average propagation speed of 15 m/s (30 mph) Type B fibers
Axons are classified into 3 groups (Types A, B, and C), this type is unmyelinated and have a propagation speed of 1 m/s (2mph) Type C fibers
what information does type B and type C fibers carry to the CNS temperature, pain and general touch sensations
type b and c motor fibers carry signals to what organs smooth muscle, cardiac muscle, and glands
what is a synapse a junction that mediates information transfer from one neuron to either another neuron or an effector cells
a (pre/post) synaptic neuron conducts impulses toward the synapse the PREsynaptic neuron conducts impulses towards the synapse
the presynaptic neuron is an information _________________ sender
the (pre/post) synaptic neuron transmits impulses away from the synapse postsynaptic neuron transmits information away from the synapse
the postsynaptic neuron is the information _______________ reciever
an axodendritic synapse is between an axon of one neuron and a dendrite of another neuron
a __________________ synapse is between an axon of one neuron and the cell body (soma) of another neuron axosomatic synapse
an axoaxonic synapse is a synapse between the axon of one axon and another axon
__________________________ synapses include direct physical contact between cells electrical
name the two different types of synapses electrical and chemical synapses
a chemical synapse is a signal transmitted across a gap by chemical neurotransmitters
in electronic synapses, what is the specific feature that allows the direct communication from the presynaptic cell to the postsynaptic cell gap junctions
in electrical synapses, the changes in the transmembrane potential are transferred ___________________ between cells though local current directly
in electrical synapses transmission is (fast/slow) fast
what is the importance of electrical synapses it gives the body the ability to synchronize several neurons together
define the term "electrically coupled" two neurons that are joined together with electrical synapses
in electrical synapses, the axolemmmas of each cell are (not/nearly) touching NEARLY touching
where in the body are most electrical synapses found Found in the brain, cardiac, and visceral smooth muscle
in the brain, what are electrical synapses responsible for programmed/automatic behaviors (i.e. breathing)
in cardiac and visceral smooth muscle what is the purpose of electrical synapses coordinated muscle activity
for electrical synapses, electrical current can flow (directly/indirectly) from one axoplasm of on neuron to the next DIRECTLY
name two unique features of electrical synapses 1) transmission is bidirectional, 2) transmission is nearly instantaneous
neural synapses that are (electrical/chemical) are much faster than chemical synapses Electrical synapses are much faster
neural synapses that are (electrical/chemical) are specialized for the release and receptions of Neurotransmitters chemical synapses uses Neurotransmitters
the axonal termial of the ______________________ neuron contains synaptic vesicles (containing the Neurotransmitters) presynaptic neuron contains synaptic vesicles
in chemical synapses, receptors on the postsynaptic neuron are located on ______________________ soma or dendrites
for an action potential to be (or not to be) propagated to a post synaptic cell, depends on what two things 1) amount of neurotransmitter released, 2) sensitivity of postsynaptic cell
what is the fluid filled space, separating the presynaptic and postsynaptic neurons in a chemical synapse the synaptic cleft/gap
the transmission across the synaptic cleft has two characteristics: what are they 1) it is a chemical event, 2) ensures unidirectional communication between neurons
name the eight steps for communication to occur across a chemical synapse 1) action potential arrives, 2) voltage-gated Ca2+ channels open, 3) Ca2+ triggers exocytosis, 4) neurotransmitter diffuses and binds to receptor, 5) postsynaptic cell is either excited or inhibited, 6) degradation, 7) reuptake, 8) diffusion
after extended stimulation, the recycling of neurotransmitter unable to keep up with demand results in ______________________ synaptic fatigue
what happens as a result of synaptic fatigue the synapse weakens until neurotransmitter can be replenished
what is the synaptic delay the amount of time between the release and the binding of a neurotransmitter
reflexes with fewer synapses are (faster/slower) than reflexes that require more synapses fewer synapses the FASTER the reflexes
what two things are occurring as long as the neurotransmitter is bound to the postsynaptic receptor 1) produces a continuous postsynaptic effect on permeability, 2) blocks reception of additional "messages."
name the three ways in which neurotransmitters are removed 1) degradation by enzymes, 2) they are reabsorbed (by astrocytes), 3) they diffuse away from synaptic cleft
neurotransmitters are considered to be ____________________________ agents paracrine
neurotransmitters are classified into what four categories 1) amino acids, 2) monoamines, 3) soluble gases, 4) acetylcholine
name three excitatory neurotransmitters 1) glutamate, 2) aspartate, 3) nitric oxide
name four inhibitory neurotransmitters 1) glycine, 2) GABA, 3) serotonin, 4) dopamine
name two neurotransmitters that are both excitatory and inhbitory 1) acetylcholine, 2) norepinephrine
four things that help to manipulate an neurotransmitter 1) rate of synthesis, 2) rate of release, 3) blocking uptake, 4) blocking degredation
name five characteristics or neuromodulators 1) effects are long term and slow to appear, 2) multiple steps, intermediary compounds, 3) alters nerve impulse transmission, 4) effect both pre/postsynaptic nerve, 5) released alone or with an NT
neuropeptides are __________________ neuromodulators that bind to receptors and active enzymes
opioids are (neurotransmitters/neuromodulators) opioids are neuromodulators
________________ bind to the same receptors as opium or morphine opioids bind to same receptors as opium/morphine
what is the purpose of opioids relieve pain (endorphins)
the same neurotransmitter released in different locations will (always have the same influence/might have different influences) on effectors might have different influences on effectors; example is ACh, usually promotes action potentials. but can also inhibit cardiac neuromuscular junctions
what can we conclude about neurotransmitters if the same neurotransmitter can have different effects on different tissues there are different subtypes of receptors for neurotransmitters
the effect of a neurotransmitter on a postsynaptic membrane depends on the properties of the receptors on the postsynaptic membrane
direct receptor mechanism in a postsynaptic channel the neurotransmitter opens ion channels directly and promotes rapid response
what types of neurotransmitters open ion channels directly ACh and amino acids
what is the indirect method of receptors in a postsynaptic channel the neurotransmitter binds to a protein which activates a second-messenger and promotes long lasting effects
what are examples of a few neurotransmitters that used second-messenger mechanisms biogenic amines, peptides, and dissolved gasses
G Protiens are (direct/indirect) mechanism of cell communication G Protiens are INDIRECT
indirect effects of neurotransmitters work through _______________________ second messengers
compared with direct effects of neurotransmitters, the indirect effects responses are _________________________________ slower, more complex, more prolonged, and often diffuse
in indirect effects, the neurotransmitter
give three examples of indirect neurotransmitters muscarinic ACh receptors, neuropeptides, and those that bind biogenic amines
in an indirect effects, the neurotransmitter binds to the receptor and the G Protein is activated . What happens next G Protien activates Adenylate cyclase to convert AT to Cyclic AMP, cAMP has several functions including (changing cell mem. permeability, activating enzymes, and activating genes)
receptors on postsynaptic cells are specialized in opening __________________-gated channels receptors open CHEMICALLY-gated channels
chemically-gated channels are relatively (sensitive/insensitive) to changes in membrane potential chemically-gated channels are INSENSITIVE to changes in membrane potential
why is it important to know that chemically-gated channels are insensitive to changes in membrane potential because it makes them unable to become self-generating
when a neurotransmitter generates graded potential that depends on what? the amount of neurotransmitter released
neurotransmitter receptors mediate changes in membrane potential according two what two things 1) amount of neurotransmitter released, 2) amount of time the neurotransmitter is bound to receptors
name the two types of postsynaptic potentials 1) EPSP (Excitatory postsynaptic potential), and 2) IPSP (inhibitory postsynaptic potential)
(EPSP/IPSP) can summate to reach threshold EPSP can summate to reach threshold
(IPSP/EPSP) can summate with EPSP to cancel each other out IPSP can cancel out an EPSP
what is summation the amount of local potentials that add up to an action potential
if the summation of local potentials are excitatory then an action potential (is/is not) initiated excitatory leads to an action potential that IS initiated
_________________________ summation is when one of more presynaptic neurons transmit impulses in rapid-fire order temporal summation is when impulses arrive in rapid-fire order
in ______________________________ summation to be successful the first impulse produces a small EPSP and a second one arrives before the first disappears temporal summation is when one impulse arrives and a second one arrives before the first disappears
__________________________ summation is when the postsynaptic neuron is stimulated by a large number of terminals at the same time spatial summation
IPSP's (can/cannot) summate IPSP's CAN summate both spacial and temporally
the neuron receives a many IPSP's and EPSP's simultaneously from different sources. the axon hillock of the neuron keeps "records" of all signals and acts as _______________________ neural integrators
the CNS has millions of neurons are organized in _____________________ neural pools
neural pools in the CNS have functional groups that 1) integrate income information, 2) forwarding the processed information
this neural circuit amplifies the signal and diverges the signal into multiple tracts Divergent
how does divergent neural circuits amplify signals they spread the signal to an increasing number of neurons as it moves through successive orders of a neuronal pathways
this neural circuit receives input from many different presynaptic neurons; as a result, the neuron has a concentrating (funneling) effect convergent circuit have a funneling effect and receives input from multiple sources
this specific neural circuit explains why different stimuli have the same effect convergent explain why different stimuli have same effects
describe a reverberating/oscillating conferenced incoming signal travels along chain of neurons containing collateral synapses with previous neurons in the chain
this particular feedback system is used in positive feedback when neural circuits re-excite the input of the same circuit reverberating/oscillating neural circuit is used in positive feedback system
what stops a reverberating/oscillating neural circuit progressive synaptic fatigue or inhibitory circuits
this particular feedback system gives a continuous signal involved in rhythmic activities such as (breathing and sleep-wake cycle) reverberating/oscillating neural circuits is used for breathing
describe a parallel after-discharge neural circuit an incoming neurons stimulate several neuron in parallel arrays that stimulate a common output cell
what is the function of parallel after-discharge neural circuit precise activity (such as solving a math calculation)
Created by: kandriot