Ch. 11 Modules 11.4-11.5

A movement of ions that increases the negativity of the resting membrane potential causes __________.

hyperpolarization

Unmyelinated axons are __________.

only partially surrounded by myelin

Schwann cells are glial cells responsible for __________.

producing the myelination around peripheral axons

The voltage that exists across the plasma membrane of an unstimulated cell is called the _______.

resting membrane potential

The two ions that are primarily responsible for stabilizing the resting membrane potential are __________.

sodium and potassium

Which type of active channels in the plasma membrane open or close when they bind certain chemicals, such as neurotransmitters?

Chemically gated channels

Satellite cells are __________.

cells that surround neuron cell bodies in ganglia and regulate interstitial fluid around the neuron

Wallerian degeneration __________.

describes the breakdown on an axon distal to the site of injury

Which of the following is NOT a characteristic of a graded potential?

(x)Propagates along the entire membrane without a decrease in strength Amount of stimulation depends on the intensity of the stimulus Can be depolorizing or hyperpolarizing Passively spreads outward in all directions from the site of stimulation with a decrease in intensity

At which of the following membrane potentials would you expect the voltage-gated sodium channels to close and the voltage-gated potassium channels to open?

+30mV

Depolarization of a neuron cell membrane will shift the membrane potential toward __________.

0 mV

What happens when a barrier prevents the movement of opposite charges toward one another?

A potential difference exists.

What type of neuroglial cell participates in the production and circulation of cerebrospinal fluid?

Ependymal cells

Which of the following is true for the sodium-potassium (Na+/K+) exchange pump?

It helps maintain the resting membrane potential by exchanging three intracellular sodium ions for two extracellular potassium ions.

What type of gated channel opens or closes in response to distortion of the membrane?

Mechanically gated channel

Which type of neuroglial cell functions in the central nervous system to engulf cellular debris, waste products, and pathogens?

Microglia

Which cells produce myelin for neurons in the CNS?

Oligodendrocytes

Tyson decides to travel overseas, but he does not get all the needed vaccines before he goes on the trip. While on his trip, he contracts diphtheria. Which type of glial cells are particularly at risk from this disease?

Schwann cells

What type of neuroglial cell myelinates axons in the peripheral nervous system?

Schwann cells

Which of the following statements about the sodium-potassium pump is correct?

The activity of the sodium-potassium pump is needed after every action potential in order to maintain the resting potential.

What forces are involved in creating the electrochemical gradient for potassium?

The chemical gradient moves potassium out of the cell, while the electrical gradient keeps potassium in the cell.

The neuroglia cells that help supply neurons with nutrients are the __________.

astrocytes

If Cl- ions were to rush into a neuron, its membrane potential would __________.

become more negative (undergo hyperpolarization)