Biopsychology Final

Which observation was not observed in Hodgkin and colleagues' voltage-clamp study of squid action potentials?

A sustained outward current as a result of hyperpolarization

Which statement best describes the action potential?

An action potential occurs when the cell's membrane potential reaches threshold.

From which part of the nervous system do cells that innervate neuromuscular junctions originate?

Central nervous system (CNS)

Which of Camillo Golgi's contributions enabled Santiago Ramón y Cajal to make observations that suggested that nerve cells are discrete entities?

Development of a staining method based on impregnation with silver salts

Which technique first produced unequivocal support for the neuron doctrine of the nervous system (as opposed to the reticular theory)?

Electron microscopy of nervous tissue

Which statement best describes the electrical properties of nerve cells?

In comparison to copper wires, they are relatively poor conductors of electricity.

Which statement about the ionic permeability of cell membranes is true?

In resting nerve cells, the membrane is quite permeable to potassium.

Which of the following is not an established role for glial cells?

Integrating information to assist neural computation

Which statement about a center-surround receptive field is false?

It is found only in primary sensory cortex.

A doctor taps the right knee in an individual who was in a car accident and has sustained damage to the right dorsal root of the lower spinal cord. Which motor response would you expect?

Right leg remains motionless

Which cell produces myelin in the nerves of the peripheral nervous system?

Schwann cell

Which statement about ionic distributions in nerve cells is true?

Sodium is higher outside cells than inside cells.

What would happen if the membrane became permeable to the Y + ions?

The Y+ ions would move into the top chamber, down their concentration gradient.

A neuron has received enough stimulation to fire an action potential; it also has been treated with TEA, a K + channel blocker. Which outcome is possible?

The cell will initially depolarize, but repolarization will take much longer because it relies only on ion pumps.

Which statement on the rising or overshoot phase of the action potential is true?

The degree of depolarization is limited in part by the inactivation time course for the sodium current.

A transgenic mouse animal model is created that expresses both the Cre recombinase gene, under control of a promoter for a gene expressed only in muscle fibers, and an androgen receptor with loxP sites around exon 2. How will expression of the androgen receptor protein be altered in the transgenic mouse?

The mouse will not express androgen receptor in muscle fibers.

Which statement regarding refractory periods is true?

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

Which statement best describes most neurons?

They are polarized.

Which statement about active ion transporters is true?

They move certain ions against the concentration gradient.

Which statement about astrocytes is true?

They play a role in the formation of the blood-brain barrier.

In a two-compartment model of a cell with a K +-permeable membrane and a 10-fold excess K + in the inside compartment, the membrane potential is experimentally made more negative than the K + equilibrium potential. How would K + ions flow across the membrane?

They would flow from the outside compartment to the inside compartment.

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

Transmits action potentials

Under which circumstances is the Goldman equation equivalent to the Nernst equation?

When a membrane is permeable to only one ion

Why is the white matter lighter than the gray matter?

White matter is richer in myelin, which reflects more light than gray matter.

Cognitive neuroscience is concerned with

all of the above perception emotion language memory

The amplitude of the action potential of a given neuron is

always the same

In the mature central nervous system, glial stem cells with the properties of astrocytes can give rise to

astrocytes, oligodendrocytes, and neurons.

An action potential occurs if current injected into a neuron _______ the neuron to reach _______ potential.

depolarizes; threshold

Neuroethology is the field devoted to studying complex behavior

in the native environment

In a two-compartment model of a cell with a K +- and Ca 2+-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 Ca 2+ ions?

it would be reduced by half

Which stimulus is most likely to evoke an action potential?

large depolarizing current pulse

Which experimental model did Hodgkin and Katz use in their studies of the resting membrane potential?

living squid neuron

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

The _______ most directly affects the rate of information processing within the central nervous system.

propagation speed of action potentials

The part of a synapse to which the contents of synaptic vesicles bind is called the

receptor

Which treatment was shown to eliminate the early inward current in squid giant axons?

removal of external sodium

Which state of the plasma membrane does not occur during an action potential?

resting phase

During which phase of an action potential does membrane permeability to Na + exceed membrane permeability to K +?

rising and overshoot phases

The technique that first revealed the tremendous diversity of neuronal cell types, by revealing different cell bodies along with their processes, is

the Golgi technique (stain).

The squid giant axon is useful in neuronal studies because

the cytoplasm in the axon can be extruded, thus allowing studies of its composition.

A dull probe stimulates a Pacinian corpuscle. An electrode is placed midway down the axon, and action potentials are recorded. After one second, the probe is pushed with greater force. What change will occur in the recording?

the frequency of action potentials will increase

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

transient inward current

The in situ hybridization method is based on

using nucleic acid probes to detect mRNAs that encode specific genes.

Which statement accurately describes the expression of genes in the nervous system?

Most of the genes in the human genome are expressed in the CNS.

Which cell type forms the structure labeled C?

Oligodendrocytes in the central nervous system

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

P K exceeds P Na at rest; P Na temporarily increases during the action potential.

Which type(s) of electrical signals occur(s) within the neural circuit for a spinal reflex?

Receptor potential, synaptic potential, and action potential