Chapter 9 Nervous System

What receives information as electrochemical messages

Dendrite

T or F. A damaged phrenic nerve would heal more slowly than a severed spinal nerve.

False

T or F. All neurons have at least one dendrite but one or more axons.

False

T or F. Calcium channels open during synaptic transmission.

False

T or F. Drugs that hyperpolarize an axon would make the nerve less sensitive to stimulations.

False

T or F. Motor neurons receive impulses from the muscles in order to regulate glandular secretions.

False

T or F. Nodes of Ranvier are only found on motor axons.

False

T or F. Norepinephrine, epinephrine, dopamine and serotonin are classed as monoamine neurotransmitters.

False

T or F. Sub-threshold stimuli can never evoke an action potential.

False

T or F. The all-or-none response means that a subthreshold stimulus can never stimulate a nerve.

False

T or F. The nodes of Ranvier function in slowing the conduction of the impulse.

False

T or F. The oligodendrocytes are capable of producing the myelin sheath that will wrap around a spinal nerve.

False

T or F. There is a higher concentration of K+ outside of a resting neuron than Na+.

False

T or F. When a neuron is resting, the outside has more potassium ions than the inside.

False

T or F. Gray matter most significantly contains cell bodies and dendrites.

False Correct Answer: It is more significant that gray matter contains synapses and cell bodies.

T or F. A synapse is a junction between two dendrites.

False Correct Answer: A synapse usually occurs either between an axon and dendrite or axon and soma.

T or F. An effector is usually a muscle or motor nerve.

False Correct Answer: An effector is usually a muscle or gland.

T or F. Convergence is a way of amplifying a stimulus through a neuronal pool.

False Correct Answer: Divergence would be a better arrangement to spread out or amplify the significance of a stimulus.

T or F. Somatic afferent fibers would carry sensory impulses away from the brain, towards areas such as the eye.

False Correct Answer: Impulses are carried in these somatic afferent fibers, away from the eye.

T or F. Sodium moves out of an axon as it is depolarizing.

False Correct Answer: Sodium rushes in and potassium moves out during depolarization.

T or F. The axon nerve impulse is self-propagating and occurs in the direction towards the cell body.

False Correct Answer: The direction of conduction within a dendrite is towards the soma.

Which part of a neuron is directly involved with protein synthesis?

Nissl body

An automatic, unconscious response to a change inside or outside the body is a ___

reflex

The following belong together except which one? A) multipolar B) motor C) sensory D) efferent

sensory

The following belong together except which one? A) interneuron B) intercalated neuron C) association neuron D) sensory neuron

sensory neuron

The three general functions of the peripheral system are __, ___, and ___.

sensory, integrative, motor

Neurons may be classified functionally as ___, ___, and ____ neurons.

sensory, interneurons, and motor

Excessive sleeping is most likely due to the presence of too much of which neurotransmitter?

serotonin

When the nerve cell is at rest, the concentration of ___ ions is relatively greater on the outside of the cell membrane.

sodium

At resting potential, the ion distribution inside and outside of a neuron is such that __________ ions are most abundant on the outside of the cell, while __________ ions are most abundant on the inside of the cell.

sodium; potassium

The cell body of a neuron is the ___

soma

The central nervous system is comprised of the brain and _____.

spinal cord

Which items should not be grouped together? A) spinal nerve B) cranial nerve C) spinal cord D) PNS

spinal cord

Which term does not belong with the others? A) brain B) spinal cord C) CNS D) spinal nerve

spinal nerve

The PNS is comprised of cranial nerves and _____.

spinal nerves

Junction between two communicating neurons is called a ___

synapse

Which part of a neuron directly contacts another neuron at the synapse?

synaptic knob

The neurilemma is composed of ___

the cytoplasm and nuclei of Schwann cells

T or F. A damaged CNS nerve could not regenerate as easily as a PNS fiber.

True

T or F. A neuron will not respond to any stimulus during its absolute refractory period.

True

T or F. Having myelin increases the velocity of conduction.

True

T or F. Impulses within a neuron always travel from the dendrite towards the axons.

True

T or F. Local potential changes are graded.

True

T or F. Most brain tumors arise from neuroglial cell overgrowth.

True

T or F. Motor neurons usually have a more complex structure than sensory neurons.

True

T or F. Nervous tissue includes areas of connective tissue.

True

T or F. Oligodendrocytes can be found within the brain.

True

T or F. The enzyme acetylcholinesterase acts to inhibit the stimulation between neurons.

True

T or F. The ion that always moves in a membrane direction opposite to sodium is K+.

True

T or F. The nucleus of a neuron is always located within the cell body region.

True

T or F. Vesicles are intracellular accumulation of neurotransmitter.

True

Which type of short neuron is found in the retina?

bipolar

Fibers that originate from different parts of the nervous system and lead to the same neuron are exhibiting _____________.

convergence

A drug, which prevents over-stimulation by the PNS neurons, is _____.

curare

The______of a neuron carries the impulse towards the nucleus.

dendrite

Branched nerve fibers that convey impulses toward the cell body of a neuron are called _____________.

dendrites

Which of the following does not belong with the rest? A) summation B) facilitation C) divergence D) convergence

divergence

Which type of neuroglial cells help regulate the composition of cerebrospinal fluid?

ependyma

The nucleus of a sensory neuron can be found within the _____.

ganglia

Nerves with ___ diameters conduct impulses faster than those with ___ diameters.

greater, smaller

In response to a stimulus, if the membrane potential becomes more negative than the resting potential, we say the membrane is _______________.

hyperpolarized

The minimal stimulus needed to cause a neuron to transmit an impulse is called the _____.

threshold

The _____ cells are capable of removing a blood clot from the brain.

microglia

The phagocytic cells in the CNS are the ______.

microglia

When a neuron reaches action potential, it depolarizes and repolarizes in an amount of time on the order of ________________.

milliseconds

Gross nerves that contain sensory impulses are referred to as _____.

mixed

The following could be grouped together except which one? A) association B) motor C) internuncial D) interneuron

motor

A neuron with many nerve fibers arising from its cell body and that carries impulses away from the brain would be classified as __________________.

multipolar and motor

List the major groups of neurons classified on the basis of structure

multipolar, bipolar, unipolar

A bundle of nerve fibers held together by connective tissue is a ___

nerve

What is the extension of a neuron cell body?

nerve fiber

What is the information transmitted in the form of electrical and chemical changes?

nerve impulse

The supporting cells of the central nervous system are the ___ cells

neuroglia

The cells of the nervous system that divide throughout life are the ___

neuroglia cells

Which of these cells does not belong with the others? A) microglia B) neuron C) astrocyte D) oligodendroglia

neuron

Transmission of nerve impulses from one neuron to another is controlled by substances called ___

neurotransmitter

Saltatory conduction occurs when an impulse jumps from _____.

node to node

The levels of which neurotransmitter are affected by the mood-elevator, cocaine?

norepinephrine

The _______________ are the types of neuroglial cells that provide myelin in the central nervous system.

oligodendrocytes

When the threshold potential is reached, the region of the cell membrane being stimulated undergoes a change in ___.

permeability

The resting potential of a neuron is _____mv.

-70

A change in a dendrite which lessens the probability of a conduction is the _____.

IPSP

Cut neurons possess limited capabilities for regeneration. The type of neuroglial cell that aids regeneration by forming a regeneration tube to help reestablish the former connection is the _______________.

Schwann cell

The cells that conduct messages towards the brain are the:

Schwann cell

Myelin sheaths on the outsides of many axons are contributed by ______________.

Schwann cells

The cells that produce myelin in the PNS are the ______.

Schwann cells

Select the incorrect statement about nerve impulse conduction.

The strength of impulses carried along a single nerve fiber can vary with the strength of their stimulus.

Which types of neurons are likely to increase muscular activities?

accelerator neurons

Myasthenia gravis reflects a deficiency in communication by _______________ because receptors for this neurotransmitter have been destroyed.

acetylcholine

The following belong together except which one? A) norepinephrine B) acetylcholine C) epinephrine D) adrenalin

acetylcholine

The most common neurotransmitter in the body is _____.

acetylcholine

Acetylcholine is decomposed by _____almost as fast as it is released.

acetylcholinesterase

The rapid sequence of depolarization and depolarization in the nerve cell is known as ___ ____

action potential

The ______cells play a role in the establishment of a blood-brain chemical barrier.

astrocyte

The _____cells provide a means of acquiring nutrients in the brain.

astrocyte

Collaterals are fibers arising from the ____of neurons.

axon

What sends information?

axon

Axons arise from a part of the cell body known as the ___ ___

axonal hillock

A morphine-like pain suppressing brain substance is _____.

beta-endorphin

Nerves that carry impulses from the heart to the brain could be classed as _____fibers.

visceral afferent