QP Test 1 Flashcards
What contains most of the “body water”?
lean body mass
The “battery” in the electrical circuit model of biological membrane is
The voltage driving driving force for each ion
In the membrane potential equation Em-Er = iRm(1 - e-t/tau), what is tau?
R(m)C(m)
In cable theory of electrotonic potential distribution, the space constant, lambda, decreases when
diameter of the axon decreases, (ADD OTHERS)
What is “Occam’s razor”?
Removing any unnecessary conditions
Na+/Ca2+ exchanger proteins move intracellular Ca2+ out of cells. Which of the following processes will directly decrease the rate of Na+/Ca2+ exchanger?
increase in Na+ concentration, (ADD any others)
What drives Ca influx through channels?
Its concentration gradient
What second messenger triggers Ca release from intracellular calcium store in the endoplasmic reticulum?
IP3
What is a function of cAMP
activation of PKA
Voltage clamp fulfills what requirement?
Ei-(Eo+Ec)=0
Neutralizes capcitative effect so all that is measured is ion current
In the Hodgkin-Huxley equation, the time independent change of potassium conductance is best fit with which power of exponential
4
What is the purpose of a voltage clamp?
To record only the resistant current
Which of the following channels mediate transmitter release at the presynaptic terminal?
Ca
“rest and digest” refers to what function
The parasympathetic division of the nervous system
What cells are responsible for myelination?
oligodendrocytes and schwann cells
Blocking the SERT transporter blocks the actions of what neurotransmitter?
serotonin
Speaking fluidly and smoothly but words are nonsensical
Wernicke’s (
Making sense but taking forever to finish the story
Broca’s
The intensity of a sensory stimulus is encoded by
The frequency of action potentials fired
The sensory afferents enter the spinal cord _______ and motor efferents exit ________.
Dorsally, ventrally
What is the main excitatory transmitter of the visual system?
Glutamate
What is in the endolymph surrounding the cilia of hair cells that generates the endocochlear potential?
High K+ concentration
What does light reach last when it enters the eyes?
Cones and Rods
What is agent based modeling?
Agent based modeling is stochastic. In a micro scale, each agent automatically controls its behavior
In cable theory of electrotonic potential distribution, what happens when the diameter of the neural axon increases?
The space constant increases
In cable theory of electronic potential distribution, what happens when there are less Na channels expressed on a fixed membrane area?
The space constant (lambda) increases
What does a bigger space constant Lambda mean for electrotonic potential propagation?
The distance of a single stimulation can propagate farther
Which nerve fiber has a bigger space constant lambda, thicker or thinner?
The thicker nerve fiber
Give three examples of transport processes that use ATP directly
- transport of Na our of cells
- transport of K into cells
- transport of Ca into ER/SR
Name four factors that cause the opening and closing of ion channels.
- voltage
- ligand-binding
- physical stretch
- phosphorylation
Name an example of transport that is not chemical specific.
Gas diffusion through cytoplasmic membrane
Which transport process characterizes the Na/Ca exchanger which moves intracellular Ca out of cells
Secondary active transport
Which protein provides the highest speed for ions moving across the cytoplasmic membrane?
ion channel
What is a second messenger?
One of a few common small intracelluar molecules that amplify the hormonal signal
Is intracellular Ca responsible for action of potential propagation along the neuron axons?
No. (what is Look It Up)
Is cCMP a second messenger?
No
Name three cellular functions of cAMP
PKA activation, regulation of ion channels, regulation of protein containing Nucleotide-Binding Domain
How does Vitamin D cross the cytoplasmic membrane?
Simple diffusion since it is a product of cholesterol.
What two factors directly determine the amplitude of a voltage gated ion channel current?
Ion concentration gradient and voltage difference across cytoplasmic membrane.
What effect does the increase of intracellular Na have on the rate of the Na/Ca exchanger?
Decrease the rate of exchange
How many different second messengers are there?
10
What is the function of inositol triphosphate (IP3)?
Triggers Ca release from the extracellular calcium store
What channel is most important in establishing resting membrane potential?
Voltage-gated K channel
By what process do CO2 transport occur in the lung?
Simple diffusion across the lipid bilayer
What is an antagonist?
A molecule that binds to a ligand receptor but does not generate a response
Name one example of a nuclear receptor
Vitamin D
Name one example of a G protein
G12/13
Hetero trimeric G-protein consists of alpha, beta, and gamma subunits. Upon the hormonal stimulation, which of the subunits binds to GTP and is separated?
The alpha subunit
Under what condition can the voltage across a membrane be clamped?
Ec = Ei - Eo
What is the purpose of voltage clamp?
Removes the capacitive current to only measure the ion flux across the membrane
In H-H equation, what power function best fits the time dependent change of K conductance?
4
What letter is used to describe the rate of change of inactivation of sodium conductance in the H-H equation?
h
In the H-H equation, what exponential function best fits the time dependent change of sodium conductance?
3
What letter is used to describe the rate of change of activation of K conductance in the H-H equation?
n
m3h gx(E-Ex) in H-H model represents _____.
Na current
Who invented the patch clamp?
Neher, Sakman
What is the difference between the patch clamp and the voltage clamp?
Patch clamp is the voltage clamp applied to a single cell
The letter h is the opening probability of the Na channel inactivation gate. What change of voltage causes the channel to inactivate (h–> 0 )?
Depolarization
What cells are responsible for myelination?
Oligodendrocytes and Schwann cells
Which channels mediate transmitter release at the presynaptic terminal?
Ca channels
What ion and direction of flow occur on the rising edge of the action potential (phase 3)?
Na ions flow into cell
What is the order of synapse types from fastest to slowest?
Gap junction, ligand-gated, G-protein coupled
What is the main fast inhibitory transmitter in the nervous system?
GABA
What are the neurotransmitters of the preganglionic neuron of sympathetic nervous system?
Acetylcholine, norepinephrine
What nervous system function is “fight or flight”?
Sympathetic nervous system
What are the three function of the cerebellum?
Movement, balance, posture
What aspect of the nervous system is involuntary?
autonomic
How many types of synapses are in the autonomic nervous system?
Two. Cholinergic and adrenergic
Sensory afferents that cross immediately when entering the spinal cord carry _____ information and ascends into which pathway?
Pain and temperature; spinothalmic tract
What is the only sensory information that doesn’t first synapse in the thalamus before reaching the cortex?
Olfactory
Where does the tonotopic organization of the auditory system originate?
Basilar membrane
How is the depolarization of taste cells in response to a salty taste mediated?
Na ions flow through an amilioride-sensative Na channel
What types of sensory receptor cells are in the visual system?
Rods and cones
What three things is the equilibrium potential of an ion dependent on?
Valence of the ion, temperature and intra and extracellular concentration
What is the main excititory neurotransmitter of the brain?
Glutamate
What makes cerebrospinal fluid?
The choroid plexus
What are 4 functions of the vagus nerve (cranial nerve 10)?
heart rate, gastrointestinal peristalsis, sweating, muscle movements of the mouth (speech, keeping the larynx open)
After crossing the medulla, ascending sensory information travels in what structure to reach the thalmus?
Medial lemniscus
What ion in the endolymph surrounding the cilia of hair cells generates the endocochlear potential? (High or low?)
High K concentration
What kind of shape change of the lens results in near-sighted vision?
Rounded
What is the “dark current” (depolarizing current) in photo sensory cells mediated by?
A continual influx of Na ions
What is the neurotransmitter of postganglionic neurons in the parasympathetic nervous system?
Acetylcholine
Most sensory information synapses in what structure where neurons then send axons to the cortex?
The Thalmus
What causes congenital birth defects such as anencephaly and spina bifida?
Failure of the neural tube to close
What current is responsible for repolarization of the cell during an action potential?
A slow-onset and continuous outward K current.
If the capactiance of a membrane is increased, what affect will it have on tau?
increase
What two factors influence the threshold for “two-point discrimination” sensory tasks?
receptor density, size of receptive field and lateral inhibition
What is the cellular response to light falling on a photoreceptor?
They hyperpolarize and refrain from releasing tranmitter in amounts corresponding to light intensity
what in the function of cholinesterase inhibitors?
The inhibition of the breakdown of acetylcholine in the synaptic cleft
Reutake of autonomic monoamine neurotransmitter is an important physilogical regulartion of synapse function. List three mechanisms that mediate the reuptake of neurotransmitters.
- serotonin transporter (SERT), blocked by selective serotonin reuptake inhibitors (SSRI)
- norepinephrine transporter (NET), blocked by tricyclic antidepresssant (TCA)
- dopomine transporter (DAT), blocked by amphetamines.
fun fact: cocaine blocks all three
What is the function of Wernike’s area? Broca’s area?
Wernike’s is understanding language. Broca’s is production of language.
Where are rods and cones located?
On the back of the retina. The light passes through layers of neurons and capillaries before ever reaching the rods and cones.
