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
