Nervous System

An inhibitory postsynaptic potential (IPSP) is associated with ________.

opening of voltage-regulated channels

hyperpolarization

a change in sodium ion permeability

lowering the threshold for an action potential to occur

hyperpolarization

Bacteria in the blood can be prevented entry to the fluids surrounding the brain. Which cells are most responsible for preventing bacteria from entering the fluids of the brain?

satellite cells

astrocytes

Schwann cells

oligodendrocytes

astrocytes

These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid ________.

oligodendrocytes

Schwann cells

astrocytes

ependymal cells

ependymal cells

Which of the following correctly describes a graded potential?

it can have amplitudes of various sizes

it travels long distances

it has a depolarization, repolarization and hyperpolarization phase

it is initiated by voltage changes in the membrane

it can have amplitudes of various sizes

Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?

norepinephrine

acetylcholine

gamma aminobutyric acid

cholinesterase

acetylcholine

When a neurotransmitter like GABA is acting in an inhibitory manner which of the following is likely a result of the GABA acting on the post synaptic cell?

influx of positively charged ions into the postsynaptic cell

opening of chemically gated sodium channels

hyperpolarization of the postsynaptic cell membrane

depolarization of the postsynaptic cell membrane

hyperpolarization of the postsynaptic cell membrane

Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane?

Specific sodium gates will open.

Sodium gates will open first, then close as potassium gates open.

Specific potassium gates will open.

A single type of channel will open, permitting simultaneous flow of sodium and potassium.

A single type of channel will open, permitting simultaneous flow of sodium and potassium.

Nerve impulses leading to the brain carry information about cool temperatures on the skin. The nerve fibers sending these signals will most likely belong to which division of the nervous system?

sensory (afferent) division

somatic nervous system

sympathetic division

parasympathetic division

sensory (afferent) division

Which of the following describes the excitatory postsynaptic potential?

moves membrane potential away from threshold

short distance depolarization

short distance hyperpolarization

opens K+ or Cl- channels

short distance depolarization

During the relative refractory period of an action potential, a larger than normal stimulus is needed to cause another action potential. This is due to the fact that ________.

the inactivation gates on voltage gated sodium ion channels are closed

the voltage gated potassium ion channels remain open long enough to hyperpolarize the axon membrane

the membrane is now impermeable to all ions

the sodium potassium pump will stop working during relative refractory

the voltage gated potassium ion channels remain open long enough to hyperpolarize the axon membrane

If a post synaptic neuron is stimulated to threshold by spatial summation this implies that ________.

the post synaptic cell has many voltage gated ion channels

the post synaptic cell is slow to repolarize

the postsynaptic cells has many synapses with many presynaptic neurons

the post synaptic cell has a lower than normal threshold

the post synaptic cells have many synapses with many presynaptic neurons

An action potential is regarded as an example of a positive feedback. Which of the following examples below best illustrates the positive feedback aspect of an action potential?

A threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarizing stimulus. This stimulus will open still more voltage gated sodium ion channels.

Voltage gated potassium ion channels open slowly and remain open long enough to cause hyperpolarization.

Potassium permeability is about 25 times greater than sodium ions.

The sodium potassium pump consistently moves ions as long as ATP is available, and regardless of membrane potential changes.

A threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarizing stimulus. This stimulus will open still more voltage gated sodium ion channels

The interior surface of a neuron's plasma membrane at resting membrane potential will have a ________.

negative charge and contains less sodium than outside of the cell

negative charge and contains more sodium than outside of the cell

positive charge and contains more sodium than outside of the cell

positive charge and contains less sodium than outside of the cell

negative charge and contains less sodium than outside of the cell

Schwann cells are functionally similar to ________.

astrocytes

ependymal cells

microglia

oligodendrocytes

oligodendrocytes

When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.

A.postsynaptic potential

B.excitatory potential

C.action potential

D.generator potential

Generator potential

When a neurotransmitter like acetylcholine is acting in an excitatory manner which of the following is likely a result of the acetylcholine acting on the post synaptic cell?

Chemically gated potassium channels will open.

Chemically gated chloride channels will open.

Chemically gated sodium channels will be closed.

Chemically gated sodium channels will open.

chemically gated sodium channels will open

Which of the following is not a chemical class of neurotransmitters?

nucleic acid

amino acid

ATP and other purines

biogenic amine

nucleic Acid

Collections of nerve cell bodies outside the central nervous system are called ________.

nerves

nuclei

ganglia

tracts

ganglia

Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone?

nitric oxide

endorphin

serotonin

acetylcholine

endorphin

The depolarization phase of an action potential is punctuated by the closing of inactivation gates in the voltage gated sodium ion channels. All of the following are consequences of this inactivation except one. Choose the statement below that is not a consequence of the closing of inactivating gates.

This allows for the one way transmission of action potential down the axon.

This limits the frequency of action potentials down the axon.

This stops the depolarization of the axon membrane.

This allows for the efflux (diffusion out) of potassium ions, resulting in the repolarization of the cell

This allows for the efflux (diffusion out) of potassium ions, resulting in the repolarization of the cell.

Like all cells, the neurons' internal organization dictates its function. Neurons have relatively many mitochondria, an extensive network of rough endoplasmic reticulum and many clusters of ribosomes. These cellular features indicate all of the following EXCEPT ________.

neurons have a relatively high consumption of oxygen

neurons must meet a high demand for ATP

neurons produce many proteins

neurons have stable, relatively unchanging internal environments

neurons have stable, relatively unchanging internal environments

Which of the following is true about the movement of ions across excitable living membranes?

Ions always move passively across membranes.

Ions always move actively across membranes through leakage channels.

Ions always move from an area of higher concentration to an area of lower concentration.

Sodium gates in the membrane can open in response to electrical potential changes.

Sodium gates in the membrane can open in response to electrical potential changes.

Which of the following is false or incorrect?

An excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold.

An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane.

A nerve impulse occurs if the excitatory and inhibitory effects are equal.

A nerve impulse occurs if the excitatory and inhibitory effects are equal.

The concentration neurotransmitters in the fluid of the synaptic cleft must be tightly regulated for neurons to function properly. Which of the following cells is most responsible for aiding in this regulation?

A) satellite cells

B) astrocytes

C) Schwann cells

D) oligodendrocytes

astrocytes

Immediately after an action potential has peaked, which of the following channels will open?

chemically gated chloride channels

voltage gated potassium channels

voltage gated sodium channels

voltage gated calcium channels

voltage gated potassium channels

If a post synaptic cell is stimulated to threshold by temporal summation this implies that ________.

the postsynaptic cell can be influenced by only one presynaptic cell

the presynaptic neuron is sending frequent IPSP

a presynaptic neuron is sending frequent EPSP

the postsynaptic cell is sending frequent action potential

a presynaptic neuron is sending frequent esps