Chapter 8 HW - Nervous System

The ________ division of the nervous system brings sensory information to the central nervous system.

afferent

Interneurons

are only found in the central nervous system

In adults, the spinal cord usually extends to which level?

first or second lumbar vertebra

If the dorsal root of a spinal nerve is severed,

incoming sensory information would be disrupted

Effects produced by the parasympathetic branch of the autonomic nervous system include

increased secretion by digestive glands

Which ion is needed to trigger the release of acetylcholine, via exocytosis, into the synaptic cleft?

calcium

Which of the following is the correct order of meninges from outside to in?

dura mater, arachnoid, pia mater

Binding of a neurotransmitter to its receptors opens _______ on the _______ membrane.

ion channels; postsynaptic

The myelin sheaths that surround the axons of some of the neurons in the CNS are formed by

oligodendrocytes

The depolarization phase of an action potential results from which of the following?

opening of Na+ channels

The arrival of an action potential at the end of an axon results in the ________.

release of a neurotransmitter fom the axon terminal

Hyperpolarization results from _______.

slow closing of K+ channels

Which of the following systems is responsible for the "fight or flight" response?

sympathetic nervous system

The repolarization phase of an action potential results from _______.

the opening of K+ channels

Head injuries that damage cerebral blood vessels are serious conditions because

these spaces compress and distort the relatively soft tissues of the brain

What is the magnitude (amplitude) of an action potential?

100 mV

The resting potential of a neuron is ________.

-70mV

1. Sodium enters the cell. 2. Cell is repolarized. 3. Voltage-gated sodium channels close as voltage-gated potassium channels open. 4. Cell is depolarized. 5. A stimulus arrives. 6. Potassium leaves the cell. 7. Voltage-gated sodium channels open

5-7-1-4-3-6-2

Which of the following is NOT an effect of activation of the sympathetic division?

constriction of the pupils

During the action potential, the inside of the cell becomes more ____ than the outside of the cell.

positive

Oligodendrocytes are to CNS as ________ are to PNS.

schwann cells

An action potential releases neurotransmitter from a neuron by opening which of the following channels?

Ca2+ channels

When the Na+ channels open, Na+ rushes into the cell causing

depolarization

If the binding of the neurotransmitter to its receptor results in the opening of Na+ channels, it will cause the membrane of the postsynaptic neuron to _______.

depolarize

In a synapse, neurotransmitters are stored in vesicles located in the _______.

axon terminals of the presynaptic neuron

The slow closing of the K+ channels means that more K+ is leaving the cell, making it more ____ inside

negative

As the K+ channels open, K+ rushed out of the cell, causing the cell to become more _____ on the inside, thus _____ the cell.

negative, repolarzing

Enlargements of the spinal cord occur

in the cervical and lumbar regions

The neurilemma of axons in the peripheral nervous system is the outer layer of

schwann cells

Where in the neuron is an action potential initially generated?

axon hillock

Which neuroglial cells produce CSF in some regions of the brain?

ependymal cells

The projections of gray matter extending through the white matter toward the outer surface of the spinal cord are called

horns

Small phagocytic glial cells, which are derived from white blood cells, are called

microglia

The ventral root carries ____ information ____ the spinal cord

motor, from

Innermost meningeal layer and is attached directly to the spinal cord

pia mater

The entire spinal cord is divided into ________ segments.

31

The ________ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity.

autonomic

The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned?

acetylcholine

Which of the following neurotransmitters usually depolarizes postsynaptic neurons?

acetylcholine

The all-or-none principle states that

all stimuli great enough to bring the membrane to threshold will produce identical action potentials.