Chapter 12

The glial cell that helps to form the blood-brain barrier is the:

astrocyte.

In order to trigger the release of neurotransmitter from a neuron terminal, calcium ions:

bind to proteins on the surface of synaptic vesicles.

When a nerve impulse reaches the transmissive segment of a neuron:

calcium diffuses into the neuron and neurotransmitter is released by exocytosis

Which functional class of neurons lies entirely within the central nervous system?

Interneurons

The type of transport protein that moves a substance down its concentration gradient is a:

channel.

Receptors are parts of the nervous system that allow it to:

collect information.

The type of neuronal circuit in which several nerve impulses come together at a single postsynaptic neuron is a ______ circuit.

converging

The glial cell that helps to circulate cerebrospinal fluid is the:

ependymal cell.

The glial cell that myelinates and insulates axons in the peripheral nervous system is the:

neurolemmocyte.

Which division of the nervous system shows a greater capacity for regeneration?

PNS

Which part of the neuron contains the nucleus?

Soma

The glial cell that myelinates and insulated axons within the CNS is the:

oligodendrocyte.

A bipolar neuron has:

one axon and one dendrite extending form the cell body.

Arrival of an action potential at the synaptic knob results in:

opening of voltage-gated calcium channels and diffusion of calcium into the synaptic knob.

The type of neuronal circuit in which several process the same information at one time is a _________ circuit.

parallel-after-discharge

What type of circuit would you use to solve a high-order mathematical problem?

parallel-after-discharge

The connective tissue wrapping that surounds bundles (fascicles) of axons is the:

perineurium.

Billions of CNS interneurons are grouped in complex patterns called neuronal:

pools:

In neurophysiology, the term summation refers to the addition of:

postsynapatic potential at the initial segment.

When voltage-gated K+ channels open on the conductive segment of a neuron:

potassium exits, repolarizing the cell to a negative value.

Most commonly, a synapse is made between a:

presynaptic neuron's axon and a postsynaptic neuron's dendrite.

The function of myeline is to:

produce faster nerve impulse propagation.

One of the ways that neurotransmitter is removed from the synaptic cleft is:

reuptake by the presynaptic cell.

The type of neuronal circuit that we continue to breathe while asleep is a __________ circuit.

reverberating

The glial cell that protects neuron cell bodies located within ganglia is the:

satellite cell.

Following damage to axons nearby, oligodendrocytes:

secrete growth-inhibiting molecules.

A mixed nerve refers to one that contains both:

sensory and motor neurons.

The afferent division of the nervous system is also know as the _____ division.

sensory.

The monoamine that has functions related to sleep, appetite, cognition, and mood is:

serotonin.

Maintenance of appropriate ion concentrations (especially after nerve impulses that involves ion diffusion) is primarily the job of:

sodium-potassium pumps.

The portion of the nervous system that has voluntary control over skeletal muscles is the _______ division.

somatic motor

The portion of the nervous system that conducts impulses from the skin, joints, skeletal muscles, and special senses is the ________ division.

somatic sensory

As an axon approaches the cell onto which it will terminate, it generally branches repeatedly into several:

telodendria.

Which statement accurately compares the transmission speed of the different types of synapess

Transmission speed of the different types of synapses.

Which is not a function of the motor division of the nervous system ?

Transmits impulses from the viscera

Typically, the resting membrane potential of a neuron is:

-70mV.

What is the most abundant glial cell in the CNS?

Astrocyte

Smatic motor neuron axons fall into the category of:

A fibers.

Which occurs first? Absolute refraction period Relative refractory period

Absolute refraction period

Where are synaptic knobs located?

At the tips of telodenria

The slowest category of nerve fibers are the:

C fibers, and they conduct impulses at 1 meter per second.

Which is true regarding the action of a neurolemmocyte?

Each neurolemmocyte can wrap only a 1mm portion of a single axon.

Which statement is true regarding the action of an oligodendrocyte?

Each obligodendrocyte can form a myelin sheath around many axons simultaneously.

Channels require energy in order to function as transport proteins.

False

Transmission of nerve impulses along myelinated axons energy than transmission along unmyelinated axons.

False

The primary inhibitory neurotransmitter in the brain is:

GABA.

What do all glial cells have in common?

They assist neurons in their respective functions.

An action potential involves a temporary reversal of polarity across the plasma membrane (that is, the inside of the axon becomes relatively positive compared to the interstitial fluid).

True

Chemical synapses are more common than electrical synapses.

True

Neurotransmitter is released from the synaptic knob by exocytosis, and it then diffuses across the synaptic cleft.

True

One main category of neurotransmitters is amino acids.

True

Saltatory conduction of a nerve impulse occurs only along myelinated axons.

True

Substance P is a neuropeptide that functions in the transmission of plain information to the brain.

True

Typically, a multipolar neuron has many dendrites and one axon extending from the cell body.

True

The spinal cord is part of the central nervous system.

Ture

A neuron conducting an impulse form the stomach wall to the CNS would be classified as a(n) _______ neuron.

Visceral sensory

Glial cells differ from neurons in that they:

are smaller and capable of mitosis.

You walk into a restaurant and amidst the sights, sounds, and smells of food preparation, you notice that you have begun to salivate. This is evidence that a particular neuronal circuit has been activated. Which one?

converging

The main way acetylcholine is cleared from a synapse is by:

degradation by an enzyme.

The type of neuronal circuit that spreads information from one presynaptic neuron to several postsynaptic neurons is a ________ circuit.

diverging

What type of circuit is used to maintain body posture while walking?

diverging

The nervous system controls the activity of muscles and glands. Muscles and glands can generate changes and are therefore called:

effectors.

When a neuromodulator slows the reuptake of a of a neurotransmitter or causes expression of an increased number of receptors on postsynaptic neurons, the effect is called:

facilitaion.

Electrical synapses involve coupling of neurons by:

gap junctions.

Potassium has a higher concentration:

inside the cell versus outside the cell, whereas sodium has a higher concentration outside versus inside the cell.

Based on function, 99 percent of neurons are:

interneurons.

A nerve:

is a cablelike bundle of parallel axons.

A depolarization is when the inside of a neuron becomes ________ the resting membrane potential.

less negative than

The glial cell that defends the body against pathogens is the:

microglial cell.

Based on structure, the most common type of neuron is the ______ neuron.

multipolar

Saltatory conduction occurs in:

myelinated axons, where action potentials occur only at neurofibril nodes.

A nerve impulse travels fastest along_____ axons of _____diameter.

myelinated, large

In a myelinated axon, the greatest concentration of voltage-gated ion channels is in the:

neurofibril nodes.

The glossy-white appearance of most axons is due to:

the high lipid content of the myelin sheath.

Wallerian degeneration involves the breakdown of:

the segments of axons and myelin sheath between the site of damage and the peripheral effector.