chapter 12

The neuron cell body houses both the ______ and the cytoplasm.

nucleus

Which neuroglial cells insulate axons in the central nervous system?

oligodendrocytes

A nerve is part of the ______ nervous system.

peripheral

Which of the following membrane transporters are present throughout the membrane of a neuron?

potassium leak channels Na+/K+ pumps sodium leak channels

Voltage represents ______ energy.

potential

A return of the membrane potential towards the resting membrane potential immediately following depolarization is called ______.

repolarization

The function of a neuron is dependent on ______.

resting membrane potentials changing

Glial cells are ______ than neurons.

smaller

The flow of ______ ion is the most common cause of depolarization.

sodium

A damaged axon within the PNS can regenerate if ______.

some neurilemma remains

"An action potential either happens or it doesn't." This statement could also be called ______.

the all-or-none law

The two factors that affect PNS regeneration are ______.

the distance between the injury site and the effector organ the amount of damage

The all-or-none law refers to the fact that action potentials will only occur if the initial segment reaches

threshold or -55mV

The conductive segment of a neuron is/are the ______.

total length of the axon

Vesicles involved in retrograde transport are moving ______ the cell body.

towards

The measure of the difference in electrical charge between two areas is called a

voltage

Events of an EPSP in order

-excitatory neurotransmitter binds to receptor Na+ channel. -Na+ enters the postsynaptic cell. -The inside of the cell becomes more positive. -The local current of Na+ becomes weaker as it moves towards the axon hillock.

Which of the following pumps can you find in the plasma membrane?

Ca2+ Na+/K+

Repolarization is due to the opening of voltage-gated _______ and the subsequent movement of _____ out of the cell.

K+

The threshold is reached when the ______ ions flow into the cell.

Na+

are large cells that ensheath many different axons.

Oligodendrocytes

Membrane pumps require ______ energy.

a lot of

norepinephrine

a monoamine neurotransmitter involved in states of arousal and attention

A synapse is a junction between

a neuron and another cell

Glutamate

amino acid neurotransmitter that excites many different neurons, leading to action

Which of the following are characteristics of neurons?

amitotic conductivity excitability extreme longevity secretion

A substance synthesized at the cell body must undergo ______ transport to reach the synaptic knobs.

anterograde

Which glial cell occupies the space of dying neurons?

astrocytes

___ are star shaped cells

astrocytes

The myelin sheath covers ______.

axon

A nerve is a bundle of parallel

axons or fibers

Cytoplasm within an axon is called ______.

axoplasm

Soma is another name for

cell body

The brain and spinal cord are part of the ______

central nervous system

The ependymal cells help produce ______.

cerebrospinal fluid

Most synapses in the human body are ______ synapses.

chemical

Synapses are classified as ______.

chemical synapses and electrical synapses

The main activity of the ______ is the propagation of an action potential along the axolemma.

conductive segment

A positive change in the membrane potential is called ______.

depolarization

A difference in the number of charged particles between two sides of the membrane forms a(n) ______.

electrical gradient

The choroid plexus is made from capillaries and ______.

ependymal cells

The lining ventricles of the brain is a location of ______.

ependymal cells

______ is responsiveness to a stimuli.

excitability

A potential that is a temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size is called a

graded potential

Glial cells are found:

in both the central and peripheral nervous system

Neuronal pools are made of ______

interneurons

During an action potential, voltage-gated potassium channels open after voltage-gated sodium channels. The effect this has on the membrane potential is ______.

it becomes less positive and more negative

The myelin sheath is made of a high percentage of ______.

lipids

Which glial cells remove debris from damaged or dead nervous tissue?

microglia

Cells that wander through the CNS and replicate in response to infection are called

microglial or microglia

If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron.

multipolar

______ neurons are most common.

multipolar

Oligodendrocytes create the_____ sheath in the central nervous system.

myelin

What is the primary tissue of the nervous system?

nervous tissue

Soma is another name for

neuron cell body

Nervous tissue is composed of glial cells and

neurons

The voltage-gated sodium channels undergo changes in activity during the depolarization phase of an action potential. Place these in order from first to last.

-membrane potential is -70mv -sodium ions flow within the neuron -the membrane potential becomes more positive -voltage-gated sodium ion channels open