Test 1

The voltage sensor of voltage gated sodium channels is made up of amino acids with positive charge T/F

True

Changes in membrane potential can induce changes in current and ion flow. When sodium's reversal potential is exceeded to the more positive side (e.g. +70 mV), what happens to Na+ flow in the neuron? A. Na+ flows out of the cell B. Na+ flows into the cell C. There is no net ion flow D. Na+ stops flowing in and out of the cell

A

How can neurons decrease resistance inside their axons (Ri)? A. Increasing axon diameter B. Decreasing axon diameter C. Myelination D. De-myelination

A

Microtubules are organized in a + and - orientation with: A. + end at ends of axons and the - end facing the nucleus B. + end facing the nucleus and the - end at the end of axons C. Kinesins moving from the + end to the - end toward the nucleus D. Dyneins moving from the - end to the + end and being responsible for slow anterograde transport

+ end at ends of axons and the - end facing the nucleus

In the knee jerk response reflex the flexor muscle (hamstring) is inhibited by: A. Release of glutamate by the muscle spindle afferent onto a GABAergic interneuron that then inhibits the motor neuron innervating the hamstring. B. Release of GABA by the muscle spindle afferent in a polysynaptic arrangement C. A circuit originating in the brainstem that releases serotonin in the ventral horn D. A long-range GABA neuron in the contralateral primary motor cortex

A

In voltage-clamp experiments, a downward deflection in current usually indicates A. Inward current (e.g. depolarlization) B. Outward current (e.g. hyperpolarization) C. Inverse current D. Low current

A

Increasing the concentration of extracellular K+ from 5mM to 30mM will do what to the neuronal membrane potential: A. Cause a depolarization B. Cause a hyperpolarization C. Have no effect at all D. None of the above

A

Radial Glia cells are considered the stem cells of the brain, arising from neuroepithelial cells. In humans, at which age are there the highest number of radial glial cells? A. Embryonic B. Adolescent C. Adult D. Elder

A

Reversal potential can be reached when permeability for a given ion becomes so high that it dominates the overall permeability of the cell. As sodium's permeability gets higher and higher during an action potential and the membrane voltage becomes more and more positive, what happens to its driving force? A. It gets smaller and smaller, eventually hitting its reversal potential B. It gets larger and larger, eventually hitting hits reversal potential. C. It remains constant and reversal potential isn't affected D. Its driving force depends on the reversal potential for potassium

A

The permeability of ions can vary at different stages of excitability and during the action potential. When a cell is at resting membrane potential, the cell membrane is most permeable to which ion? A. K+ B. Na+ C. Cl- D. Ca2+

A

What magnitudes of tau and lambda might you expect in a synaptic connection that is highly efficacious (e.g. a synapse that has undergone LTP)? A. Large tau and large lambda B. Large tau and small lambda C. Small tau and large lambda D. Small tau and small lambda

A

Which of the following would occur if a neuron had increased sodium ion permeability? A. Resting membrane potential would become more positive B. Resting membrane potential would become more negative C. Resting membrane potential would not change D. Resting membrane potential would cease to exist

A

Golgi's Reticular Theory and Ramon y Cajal's Neuron Doctrine rivalled each other in the way neurons were portrayed in the brain. How were the two theories different? A. Cajal's theory stated that all neurons were connected to each other throughout the brain using electrical synapses. B. Golgi's theory stated that all neurons were individual cells, separate from each other by neurochemical synapses. C. Golgi's Reticular Theory is now more widely accepted because of the way it describes neurons as continuously connected together in the brain through a net. D. Cajal's theory is now more widely accepted because of its hypothesis, which we now know is true, that neurons are individual, non-continuous cells that allow for cell to cell communication in the brain through synapses.

A. Cajal's theory is now more widely accepted because of its hypothesis, which we now know is true, that neurons are individual, non-continuous cells that allow for cell to cell communication in the brain through synapses.

Which of the following have the capacity to activate microglia A. Ischemia B. Bacteria C. Cytokines D. All of the above

D

A cell's resting membrane potential can be calculated through the Goldman Equation. Goldman's Equation is different than the Nernst Equation because it introduces the concept of what? A. Various protein pumps such as Na+/K+ ATPase B. Permeability of individual ions C. The opening of chloride channels D. The creation of ion gradients

B

How do dendrites usually increase their capacity to passively conduct current? A. They decrease their diameter causing the time constant to increase B. They increase their diameter causing the time and length constant to increase C. They become myelinated D. All dendrites are the same and never change

B

How would you describe the current generated from negatively-charged ions flowing into the cell? A. Inward current B. Outward current C. Inverse current D. Low current

B

If the myelin sheath surrounding the axon of a neuron were to degrade, which of the following would occur? A. The length constant would increase B. The length constant would decrease C. the axon would die D. nothing would happen

B

In what direction would a positively-charged ion flow if ion channels permeable to the ion opened when the resting membrane potential was more positive than the equilibrium potential for that ion? A. Into the cell B. Out of the cell C. There would be no net flow of X D. Impossible to determine with the given information

B

Ohm's law is written as Vm - Vequilibrium potential = I*R when considering currents in the nervous system because when Vm = Vequilibrium potential there is ___________ net current flow. A. Infinite B. Zero C. Very large D. None of the above

B

Pseudo-unipolar neurons have a single axon coming off the cell body that then splits off into two axons and are usually found in: A. The brain stem B. Dorsal root ganglion C. The ventral horn of the spinal cord D. Hippocampus

B

The permeability of ions can vary at different stages of excitability and during the action potential. When the cell first reaches action potential threshold, the cell membrane is becoming most permeable to which ion? A. K+ B. Na+ C. Cl- D. Ca2+

B

The value of the resting membrane potential is most dependent upon the permeability of which ion species according to the Goldman equation? A. Sodium B. Potassium C. Chloride D. Calcium

B

What prevents the action potential from propagating backwards? A. Sodium channel closing B. Sodium channel inactivation C. Biophysical properties of ankyrin G at the axon hillock D. Sodium channel voltage sensors

B

When blocking specific ion channels, significant changes in current can be observed during the action potential. What can be observed with TTX, the Na+ channel blocker? A. Mainly inward currents remained B. Mainly outward currents remained C. Outward currents for the first half, inward currents for the second half D. Inward currents for the first half, outward currents for the second half

B

Which of the following statements about action potentials are false? A. They are all or none B. They are usually induced by hyperpolarization C. They require voltage gated sodium channels D. They occur when the membrane potential reaches "threshold"

B

Which type of axon would have the fastest action potential conduction velocity? A. Small, myelinated axons B. Large, myelinated axons C. Axons with a small length constant D. Axons with a very long time constant

B

Which type of glial cell increases the conduction velocity of action potentials in the peripheral nervous system by promoting saltatory conduction? A. Oligodendrocytes B. Schwann cells C. Astrocytes D. Microglia

B

The transcriptome for a given tissue refers to the mRNAs that are expressed in that organ. Which of the following statements are correct? A. The brain and heart transcriptomes are remarkably similar B. The brain's transcriptome is distinct compared to other tissues in the human body C. The brain doesn't have a transcriptome D. Only about 2000 mRNAs are expressed in the brain, which is far lower than in the heart Q

B. Brain's transcriptome is distinct compared to other tissues in the human body

When microglia are activated they enter a state where they release cytokines and take on many properties that are normally associated with macrophages in the periphery during an immune challenge. What is this state called? A. Resting state B. Phagocytic state C. Astrocytic state D. All of the above

B. Phagocytic state

Approximately how excitable are neurons during the peak of an action potential when voltage gated sodium channels are entering the inactivation phase? A. Very excitable B. Somewhat excitable C. Not excitable D. Depends heavily on neuronal subtype

C

Na+ channels and K+ channels are different in their time course for opening and closing. What is the typical time course for a Na+ ion channel? A. Slow and non-inactivating B. Slow and inactivating C. Fast and inactivating D. Fast and non-inactivating

C

Neurons, sitting at resting membrane potential, normally have a high ____ potassium ion concentration and a high ____ sodium ion concentration. A. Extracellular , Extracellular B. Extracellular , Intracellular C. Intracellular , Extracellular D. Intracellular , Intracellular

C

The BOLD signal in functional MRI is most dependent upon changes in blood flow in the brain that are regulated by which type of cell? A. Pyramidal neurons B. Inhibitory interneurons C. Astrocytes D. Microglia

C

The Nerst equation incorporates multiple variables such as ion concentration, temperature, and the charge of ions. What is the main purpose of using the Nerst equation? A. To solve for individual ions' permeability factors B. To solve for the ratio of extracellular and intracellular concentrations of an ion C. To solve for the equilibrium potential / reversal potential of an individual ion D. To solve for a cell's condition at different temperatures

C

What would happen to the potassium ion conductance if you added tetrodotoxin (TTX) to your electrophysiological preparation? A. Potassium ion conductance would increase B. Potassium ion conductance would decrease C. Potassium ion conductance would not change D. Potassium ion conductance would be reduced to zero

C

The rate at which neurons can fire action potentials is most dependent on A. Action potential amplitude B. Action potential duration C. Relative refractory period D. B and C

D

The resting membrane potential in neurons is primarily determined by which two ions: A. Na+ and Mg2+ B. Na+ and Cl- C. K+ and Ca2+ D. K+ and Na+

D

There are two types of refractory periods: absolute and relative. What does the absolute refractory period depend on? A. Na+ channels being open B. K+ channels being open C. K+ channels being closed D. Inactivation of Na+ channels

D

Voltage gated sodium channels have how many transmembrane domains per individual protein? A. 12 B. 48 C. 8 D. 24

D

When many ion channels are opened, what happens to conductance and resistance? A. Conductance decreases; Resistance increases B. Conductance increases; Resistance increases C. Conductance decreases; Resistance decreases D. Conductance increases; Resistance decreases

D

Regulating intracellular calcium is critical for neurons because too much intracellular calcium can cause excitotoxicity. Which of the following organelles play a key role in buffering calcium in neurons? A. Nucleus and mitochondria B. Golgi and rough ER C. Endoplasmic reticulum and mitochondria D. Mitochondria and myelin

Endoplasmic reticulum and mitochondria

TRUE or FALSE. The equilibrium potential of potassium is the membrane voltage at which no potassium ions are physcially allowed to cross the membrane.

False

What kind of transport is dependent on kinesin motor proteins? A. Fast retrograde B. Fast anterograde C. Slow retrograde D. Slow anterograde

Fast anterograde

Increasing intensity and duration of a stimulus will increase action potential ___________, but its _____________ remains the same. A. Upshoot, Undershoot B. Amplitude, Frequency C. Frequency, Amplitude D. Undershoot, Upshoot

Frequency, Amplitude

Translation is the process of creating peptides from mRNAs. What is the rate limiting step in translation regulation? This is the step that is most heavily influenced by cellular kinases and is involved in neuronal plasticity. A. Initiation B. Elongation C. Termination D. Transcription

Initiation

Local mRNA translation can control neuronal plasticity. Which of the following are types of neuronal plasticity that are regulated by local translation? A. Long Term Potentiation B. Long Term Depression C. A and B D. None of the above

Long Term Potentiation AND Long Term Depression

Myelin in the CNS is made by: A. Schwann cells B. Astrocytes C. Oligodendrocytes D. Both A and C

Oligodendrocytes

TRUE or FALSE. The sodium-potassium ATPase pump is an example of a transmembrane ion channel that requires energy.

True

The length constant (l) has a greater value in axons that are myelinated.

True