Kines 360 Exam 1

Which movement disorder is associated with deficits in the basal ganglia?

Huntingdon's disease, and Parkinson's disease

The refractory period can be considered to operate using activation and inactivation gates. Repolarization (change in membrane potential that returns it to a negative value) of membrane potential begins about 1 msec after the activation gate opens. What happens next

Inactivation gate closes to stop the passage of sodium ions

Layer 4

Internal granular= receives information

Which statement best describes the function of a neuron with multiple, highly branched dendrites and one axon?

It integrates information from many neurons

Which statement about electrochemical equilibrium is true?

It occurs when the potential across the membrane exactly offsets the concentration gradient

what is the major determinant of the permeability of a membrane to a specific ion?

Number of open ion channels specific for that ion

Which meningeal layer is located closest to the brain?

Pia mater

Dendrites

Receive many signals from other neurons and receive, process, and transfer these to the cell body (soma)

Which property(ies) of the action potential do the graphs in the figure illustrate? There could be multiple correct answers. Pick at least one

Refractoriness, all-or-none, and polarized propagation

Epithalamus

Regulation of circadian rhythms

Thalamus

Relays sensory and motor signals, and regulation of alertness

A Na+/K+ ATPase pump is responsible for maintaining concentration gradients for both Na+ and K+ ions. Which intervention will disrupt the function of the Na+/K+ATPase pump?

Removal of extracellular K+

A neuron that innervates (i.e., makes synaptic contact with) a large number of other neurons

Represents divergent neural signaling

The resting membrane potential typically ranges from ___ to ___.

-40mv to -90mv

How many layers are there in the cerebral cortex?

6

Which conclusion can be drawn from the studies of K+ and Na+ conductances?

Both conductances exhibit the property of time-dependent activation, Both conductances depend on voltage, K+ conductance reaches its maximum with a pronounced delay, Unlike K+ conductance, Na+ conductance reaches its maximum and inactivates rapidly

The amplitude of the action potential of a given neuron is

always the same

temporal lobe

auditory

Dorsal telencephalon becomes the___

cerebral cortex

Hypothalamus

controls hormone system, and homeostasis such as, hunger, thirst, body temp, reproduction

The large white matter tract that connects the two hemispheres is the ___

corpus callosum

Gyri/gyrus

crests of folded cortical tissue

Which statement about Na+ permeability during an action potential is most accurate?

it is responsible for the rising phase of the action potential

The major arterial supply to the frontal, parietal, and temporal cortical regions that areimportant for motor control and speech is derived from the ___

middle cerebral artery

frontal lobe

motor and cognition

The spinal cord does NOT play an important role in __

movement planning

Which of the neurons below have the highest degree of convergence? Click on the picture below.

neurons with MANY dendrites

In a two-compartment model of a cell with a K+-permeable membrane, at K+ equilibrium potential, there is ___ flux of K+ ions.

no net

Which cranial nerve is actually a part of the diencephalon?

optic nerve

Which cranial nerves enter the forebrain directly?

optic nerve, and olfactory nerve

The parieto-occipital sulcus is a very deep sulcus that crosses the posterior part of the hemisphere and divides the internal occipital lobe from the ___ lobes

parietal

Decussation is the point in the central nervous system at which a major ascending sensory pathway crosses the midline. Where in the brainstem do most of the ascending fibers typically cross the midline?

pons, and medulla

Relative to the spinal neuraxis, dorsal refers to __, while ventral refers to ____.

posterior, anterior

Watch the video on Canvas for Lesson 2b and answer the following question. During which phase of an action potential does membrane permeability to Na+ exceed membrane permeability to K+? NO CORRECTNESS POINTS.

rising and overshoot phases

occipital lobe

vision

Ion channels that are involved in generation of action potentials open or close in response to

voltage

Areas containing axonal tracts are called ____ matter

white matter

Myelin is ______, while areas with cells, dendrites, and unmyelinated axons appear _______

white, gray

Calculate the equilibrium potential for at room temperature. Use the formula shown below. The charge on a sodium ion, z=1. Assume that (RT/zF)=25.7. mM is the extracellular concentration and mM is the intracellular concentration.

-59mv

Calculate the membrane potential. Use the formula shown below. Assume that the permeability of chloride ions is zero.(RT/zF)=25.7. mM is the extracellular concentration of mM is the intracellular concentration of is the permeability of mM is the extracellular concentration of mM is the intracellular concentration of is the permeability of

-63mv

Axon

A singular fiber that carries info away from the soma to the synaptic sites of other neurons

Which statement about myelination is FALSE? A. Myelin sheaths are created by glial cells B. Myelin serves to sharply decrease the conduction of action potentials C. Multiple layers of closely opposed glial membranes wrap the axon and serve as an electrical insulator D. Myelin is absent at the nodes of Ranvier E. Sodium and potassium channels are clustered at the nodes of Ranvier

B. Myelin serves to sharply decrease the conduction of action potentials

In the class we talked about pain perception and Na+ ion channels. Read the textbook and answer the following question. What is the mechanism of action of most local anesthetics?

Block Na+ channels involved in the generation of action potentials

Which one is NOT a main function of the glial cells? A. Support signaling function of nerve cells B. Contribute to the development of nerve cells C. Communicate neural information across brain areas via chemical and electrical signaling D. Contribute to the repair of the nervous system E. Form myelin sheaths in the nervous system

C. Communicate neural information across brain areas via chemical and electrical signaling

Which statement regarding refractory periods is true? A. They allow neurons to fire an unlimited number of action potentials per unit of time B. During the refractory period the cell requires a less intense stimulus to reach threshold C. The refractory period ends when the sodium channels are no longer inactivated D. The refractory period arises in part due to the increase in sodium conductance across the membrane E. The refractory period arises in part due to the decrease in potassium conductance across the membrane

C. The refractory period ends when the sodium channels are no longer inactivated

The cerebral ventricular system is made up of 4 ventricles that include two lateral ventricles in the cerebrum, the third ventricle in the diencephalon, and the fourth ventricle in the hindbrain. Which area is NOT a part of the hindbrain? A. Pons B. Cerebellum C. Medulla Oblongata D. Insula

D. Insula (NOT part of hindbrain)

Which of the following neurons has the lowest divergence? Click on the neuron below.

D.) Retinal anacrine cell (has a few dendrites)

Which statement about voltage-gated ion channels is TRUE? A. Without sodium channels, no current flows out B. Without potassium channels, no current flows in C. Na+ channels open after a short delay D. K+ channels close after a short delay E. Na+ and K+ channels can work independently of one another

E. Na+ and K+ channels can work independently of one another

Which statement about active ion transporters is TRUE? A. Which statement about active ion transporters is true? B. They are functionally similar to ion channels C. They allow ion movement down the concentration gradient D. They move all ions against the concentration gradient E. They move certain ions against the concentration gradient

E. They move certain ions against the concentration gradient

Which statement regarding membrane potential and equilibrium potential is true?

Equilibrium potential is affected by the concentration and electrical gradients of one ion; membrane potential is affected by gradients of all ions

Which property is characteristic of Na+ channels but not K+ channels?

Inability to inactivate slowly

Layers 5 and 6

Infragranular= sends output from cortex to the brainstem or spinal cord

Subthalamus

Integration of somatic motor function

How will a neuron transmitter respond if an experimenter injects negative current into the intracellular space? (injection of -ve current is the same as outward +ive current)

It will become hyper polarized

How will a neuron respond to an injection of negative current?

It will become hyperpolarized

In a two-compartment model of a cell with a K+-permeable membrane and a 10-fold excess of K+ in the inside compartment, how would the membrane potential change if all K+ ions were replaced by Na+ ions?

It would Not change, and NO potential would be generated

Concentrations of which ion, inside and outside of a neuron, have the greatest effect on the resting membrane potential?

K+

Which glial cell type serves as a resident immune cell in the central nervous system?

Microglia

Basal ganglia function

Motor control, reward, and cognition

Voltage-gated ions

Na+ and K+ channels can work independently of one another

How does membrane permeability to K+ (PK) and Na+ (PNa) change during an action potential?

PK exceeds PNa at rest; PNa temporarily increases during the action potential

In the figure below, the relationship between resting membrane potential and external concentration of K+ is shown. The straight black line represents a slope of 58 mV per ten-fold change in concentration of K+ in extracellular space. Why is that different from the red line observed in real experiments conducted with giant squid axons?

Resting membrane potential depends on multiple ions

Which region of the brain would be involved in planning and execution of complex movement? Ex: a B-ball free throw

Telencephalon

Telencephalon= ___ nerve Diencephalon=___ nerve

Telencephalon= olfactory nerve Diencephalon= optic nerve

Which statement correctly differentiates between the passive and active current in a myelinated axon?

The active current flows only in the nodes of Ranvier, unlike the passive current

Which statement does the graph illustrate?

The behavior of Na+ channels is voltage dependent

Which consequence of Na+ channels staying open, instead of closing after membrane depolarization, is most plausible?

The membrane would not repolarize (return to a negative value of membrane potential) following depolarization

The central sulcus divides the ___ and ____ lobes

frontal, parietal

Regions of cells are called ___ matter

gray matter

sulci/sulcus

grooves/ spaces that divide gyri

During the knee jerk reflex, the role of the spinal interneuron is to ___ the ___ muscle, allowing the leg to ___.

inhibit, flexor, extend

Primary function of corpus callosum

integrate and transfer information from both cerebral hemispheres to process sensory, motor, and cognitive signals

In the phase labeled B, the voltage-gated sodium channels are ____ and the voltage-gated potassium channels are ____.

open, closed

sensory afferents are ___ neurons

peripheral

Nodes in ranvier represent

points where 2 axons connect

Cell body (soma)

produces all the proteins for the dendrites, axons, and synaptic terminals

An action potential travels in only one direction along the axon because of its ___ property.

refractory

Watch the video uploaded on Canvas for Lesson 2b and answer the following question. Which state of the plasma membrane does not occur during an action potential?

resting phase

In the phase labeled B, ___ ions are moving ___ the cell.

sodium, into

parietal lobe

somatosensory

Relative to the spinal neuraxis, a rostral location is more___ than a caudal location.

superior

Relative to the forebrain neuraxis, dorsal refers to ___, while ventral refers to ___.

superior, inferior

Layers 1-3

supragranular= communication

Lateral fissure divides the ____ lobe from the ___ and ___ lobes

temporal; frontal, parietal

Which of the following is the key event when the membrane potential is depolarized to 0 mV? Refer to the figure below.

the early inward current is at its maximum

Which of the following is the key event when the membrane potential is depolarized from 26 mV to 52 mV? Refer to the figure below.

the late outward current increases I magnitude and the early inward current reverses its polarity

Nerst potential for Ca2+ ions is 100+mv, much more depolarized than the peak of the action potential. This means that

When Ca2+ channels open, Ca2+ ions will enter the cell with great driving force

The proteins that establish ionic gradients are called

active transporters

Ion channels

allow ions to move across the membrane quickly work with the electrochemical gradients to pass ions exist in distinct variants, allowing different types of ions to pass respond to changes in the membrane potential

Relative to the forebrain neuraxis, a rostral location is more _ than a caudal location.

anterior

The resting potential of a cell is negative because

at rest there is an excess of K+ inside the cell, and the membrane is permeable chiefly to K+ and many of the molecules needed for life - nucleic acids, amino acids, and proteins - are negatively charged molecules or anions. Most of these are too large to leave the cell.

Cerebellum

balance and posture

Ventral telencephalon becomes the ____

basal ganglia

Studies of the ionic basis of the action potential has shown that

decreasing sodium outside the cell decreases the size of the action potential

Studies of the ionic basis of the action potential in squid giant axon found that

decreasing sodium outside the cell decreases the size of the action potential

Which function is a characteristic primarily of neurons only, and not glia?

Transmits action potentials

Which feature do the three transporters shown in the figure share?

Transport of some ions down their concentration gradient and others up their gradient

The three cardinal spatial planes through the brain are (select ALL correct answers)

Transverse/horizontal/axial, coronal/frontal, and sagittal

True or False: The internal capsule has white mater tracts that connect the thalamus with the cerebral cortex. In addition, the internal capsule has axons which descend from the cortex to the brain stem.

True

How does the resting membrane potential of a typical neuron compare to the equilibrium potential (calculated by the Nernst equation) for potassium?

The resting membrane potential is not exactly equal to the equilibrium potential for potassium because the membrane has some resting permeability to species other than potassium

Which process(es) underlie(s) the refractory period?

The slow time course of turning off K+ conductance activation and the persistence of Na+ conductance inactivation

On which body part would the two-point discrimination threshold be shortest?

Thumb

Which current corresponds to a flow of Na+ in response to a depolarizing stimulus in a giant axon of a squid?

Transient inward current