Lab 6

Which of the following statements about receptor potentials is FALSE? They can trigger an action potential. The receptor proteins respond to stimuli. The receptor potential is carried by neuroglia. Odor molecules can act as stimuli.

Which of the following is NOT a functional region of a neuron? conducting region secretory region medullary region receiving region

The conducting region of the neuron is the _______. dendrite axon axon terminal cell body

The typical concentration of sodium is _______. the same as potassium intracellularly. lower than potassium intracellularly. higher than potassium intracellularly. lower than potassium extracellularly.

Which of the following describes a change from the resting membrane potential? an action potential a receptor potential a receptor potential, a synaptic potential or an action potential a synaptic potential

What effect did increasing the extracellular potassium have on the resting membrane potential? The resting membrane potential did not change. The resting membrane potential became less negative. The resting membrane potential disappeared. The resting membrane potential became more negative.

What effect did decreasing the extracellular sodium have on the resting membrane potential? The resting membrane potential disappeared. The resting membrane potential became less negative. Only a small change occurred, because the resting neuron is not very permeable to sodium. Only a small change occurred, because the sodium channels were mostly open.

The channels that provide for the movement of potassium in the resting neuron are _______. chemically gated leakage and chemically gated. voltage gated leakage

Establishing the resting membrane potential requires energy through the use of the _______. sodium leakage channels sodium-potassium pump sodium-glucose pump potassium-glucose pump

The receptor potential is generated at the _______. receiving region secretory region output region conducting region

Sensory transduction is defined as _______. the conversion of a stimulus to a change in membrane potential the disappearance of the perception of a stimulus a change in the amplitude of a receptor potential the conversion of a light stimulus into pain

The receptor potential _______. requires the appropriate stimulus amplitude can vary with the stimulus intensity, requires the appropriate stimulus and can be graded with a stimulus intensity can be graded with stimulus intensity amplitude can vary with the stimulus intensity

Which of the following describes a depolarization? The membrane potential becomes more negative. The membrane becomes less polarized. The membrane potential becomes more polarized. The membrane, which was formerly not polarized, now is polarized.

Which of the following was able to detect pressure? Pacinian corpuscle olfactory receptor free nerve ending the Pacinian corpuscle and the free nerve ending

Which of the following does NOT describe graded potentials? They are always depolarizing. They are local changes. They are changes to the membrane potential. They vary with the intensity of the stimulus.

Which of the following responded to a chemical stimulus? free nerve ending olfactory receptor both the Pacinian corpuscle and the olfactory receptor Pacinian corpuscle

When the intensity of the appropriate stimulus was increased, the amplitude of the response _______. did not change decreased increased was zero

A nerve is _______. another term for a neuron another term for nerve fiber a cluster of cell bodies a bundle of axons

The region on the neuron where action potentials are generated is called the ______. stimulator zone trigger zone depolarization zone dendrite

In this simulation, ___________________ will be used to stimulate the axon. voltage light chemicals heat

We describe the regeneration of the action potential down the membrane of the axon of the neuron as _______. propagation hyperpolarization conduction conduction or propagation

The minimum voltage that is required to generate an action potential is called the _______. propagation voltage threshold voltage trigger voltage depolarization voltage

Increasing the voltage resulted in which of the following? a decrease in the rate of propagation of the action potential no change to the action potential an increase in the size of the action potential an increase in the rate of propagation of the action potenti

An axon that is more negative than the resting membrane potential is said to be _______. graded at threshold depolarized hyperpolarized

If an increase in extracellular potassium hyperpolarizes a neuron, which of the following would be correct? It would change the membrane potential to a less negative value. It would increase the flow of sodium out of the cell. It would decrease the flow of sodium out of the cell. It would change the membrane potential to a more negative value.

An action potential requires _______. sodium to flow with its electrochemical gradient voltage-gated sodium channels to open voltage-gated sodium channels to open and sodium to flow with its electrochemical gradient chemically gated sodium channels to open

To reach threshold, the amount of sodium _______. entering the cell must overcome the potassium exiting exiting the cell must overcome the potassium entering exiting the cell must overcome the potassium exiting entering the cell must overcome the potassium entering

Which of the following blocks voltage-gated sodium channels? potassium tetrodotoxin and lidocaine lidocaine tetrodotoxin

Which of the following is used to block pain? tetrodotoxin and lidocaine tetrodotoxin lidocaine potassium

Which of the following occurred in the presence of tetrodotoxin? The number of action potentials increased. The size of the action potential decreased. The size of the action potential increased. The number of action potentials decreased.

Which of the following occurred in the presence of tetrodotoxin? An action potential was always seen at R1. An action potential was always seen at R1 and R2. An action potential was always seen at R2. All action potentials were missing.

In the presence of lidocaine, the action potential was NOT affected at R1 because _______. there are no voltage-gated sodium channels to be affected lidocaine was applied upstream of R1 lidocaine doesn't have an effect on the generation of action potentials lidocaine was applied downstream of R1

The effects of lidocaine and tetrodotoxin were _______. identical similar, but tetrodotoxin had a greater effect similar, but lidocaine had a greater effect very different, because lidocaine had no effect

Which of the following occurs first in the generation of an action potential? The membrane repolarizes. Voltage-gated sodium channels open. The membrane depolarizes. Voltage-gated potassium channels open.

Which of the following occurs during depolarization? Sodium flows into the cell. Both A and C occur. Voltage-gated potassium channels close. Voltage-gated sodium channels close. All of the above occur.

Which of the following occurs during repolarization? Voltage-gated potassium channels open and potassium flows into the cell. Voltage-gated potassium channels remain open and some voltage-gated sodium channels inactivate. Potassium flows into the cell. Voltage-gated sodium channels open. Sodium flows into the cell. Voltage-gated potassium channels open and some voltage-gated sodium channels inactivate. Potassium flows out of the cell. Voltage-gated sodium channels open and some voltage-gated potassium channels inactivate. Sodium flows out of the cell.

Which of the following allow the movement of potassium through the neuronal membrane? simple diffusion leakage channels voltage-gated potassium channels leakage channels and voltage-gated potassium channels

Why does the threshold increase when the interval between the stimuli decreases? Sodium is flowing out of the cell. Potassium is flowing into the cell. Calcium is flowing out the cell. Some sodium channels have been inactivated and cannot be reopened immediately.

During the relative refractory period, _______. another action potential can be generated provided the stimulus is large enough. another action potential can be generated provided the stimulus is relatively smaller than the original stimulus. a second action potential cannot be generated, no matter how strong the stimulus. the flow of potassium is also depolarizing the neuron.

When the interval between the stimuli decreases, _______. a second action potential is generated regardless of the stimulus and the interval a second action potential is generated as long as the stimulus is above threshold a second action potential is generated until the interval reaches the relative refractory period a second action potential is generated until the interval reaches the absolute refractory period

When the stimulus voltage is increased, _______. sodium permeability into the cell increases to overcome the potassium exiting a greater-than-threshold depolarization results sodium permeability into the cell decreases a greater-than-threshold depolarization results and sodium permeability into the cell increases to overcome the potassium exiting.

When the stimulus intensity increases, _______. the number of action potentials decreases the number of action potentials increases the size of the action potential increases the size of the action potential decreases

In this activity, which of the following will increase the stimulus intensity? increasing the relative refractory period decreasing the absolute refractory period increasing the duration of the stimulus increasing the absolute refractory period

At threshold, axons will _______. Usually be at the end of their absolute refractory period. Always generate an action potential. Begin to hyperpolarize the membrane potential. Likely generate an action potential if refractory periods have elapsed.

Longer stimuli will allow for _______. the relative refractory period to finish more action potentials to occur the absolute refractory period to finish more action potentials to occur, the absolute refractory period to finish and the relative refractory period to finish

The time interval between action potentials is called the _______. potential frequency threshold interval threshold frequency interspike interval

Increase in stimulus intensity _______. increases the frequency of action potentials has no effect on action potentials increases the size of the action potential increases the duration of the action potential

The frequency of action potentials is _______. measured in hertz, and the same as the relative refractory period the same as the relative refractory period the reciprocal of the interspike interval, and measured in hertz the reciprocal of the interspike interval measured in hertz

During the relative refractory period, _______. the stimulus must be above threshold to generate an action potential adaptation occurs the stimulus must be below threshold to generate an action potential no action potentials are generated

Which of the following is described correctly? Schwann cells provide the myelination in the peripheral nervous system. Oligodendrocytes provide the myelination in the peripheral nervous system. Schwann cells provide the myelination in the central nervous system. Astrocytes provide the myelination in the central nervous system.

The rate with which an action potential travels along an axon _______. is called the conduction velocity and is measured in volts/sec is measured in meters/sec is called the conduction velocity and is measured in meters/sec is called the conduction velocity is measured in volts/sec

Which of the following describes a B fiber? large diameter, lightly myelinated small diameter, lightly myelinated medium diameter, lightly myelinated small diameter, unmyelinated

The nodes of Ranvier are _______. locations on the axon where the myelin sheath is absent locations on the axon where the myelin sheath is very heavy trigger zones of an axon a type of glial cell

Which fibers generate the smallest value for conduction velocity? C fibers B fibers D fibers A fibers

The time interval for conduction would be shortest with the smallest unmyelinated axons the largest and most heavily myelinated axons the largest unmyelinated axons the smallest and most heavily myelinated axons

Increasing the amount of myelination _______. has no effect on the time between action potentials decreases the time between action potentials increases the time between action potentials increases the time between action potentials only for small-diameter axons

In this activity, the stimulus voltage used was _______. altered to accommodate the structural differences suprathreshold for all of the axons the same for all of the axons the same for all of the axons and suprathreshold for all of the axons

What are membrane potential and action potential?