Chapter 12 study questions
A nerve is part of the ____ nervous system.
peripheral
An inhibitory postsynaptic potential results from the opening of
potassium and/or chloride channels
Membrane molecules that use the energy of ATP to move ions against a concentration gradient are called
pumps
_____ is the return of polarity from positive back to negative (the RMP).
repolarization
The function of a neuron is dependent on
resting membrane potentials changing
glial cells are ______ than neurons
smaller
Normally, sodium and potassium leakage channels differ because ___________________.
sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell
A damaged axon within the PNS can regenerate if ______.
some neurilemma remains
Vesicles involved in retrograde transport are moving ______ the cell body.
toward
If a sub threshold value is reached on an axon membrane, an action potential
will not occur
Which of the following membrane transporters are present throughout the membrane of a neuron
-Sodium leak channels -Na+/K+ pumps -Potassium leak channels
Place the events of EPSP In order
1. The excitatory Neurotransmitter binds to the chemically gated cat ion channel 2. More Na+ enters the postsynaptic cell then k+ leaves 3. The inside of the cell becomes more positive 4. The local current of NA+ becomes weaker as it moves towards the axon hillock
If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result?
Acetylcholine would build up in the synaptic cleft.
Action potentials are always propagated along an axon at the same______ but ____ can vary depending on the strength of the frequency
Amplitude; frequency
At the synaptic knob, voltage-gated________ channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis
Calcium
The presence of _________ions cause the synaptic vessels a bind to the membrane allowing Neurotransmitters to be released
Calcium
resting membrane potential of -70 mV indicates that the_______.
Charges lining the inside of the plasma membrane are negative compared to the charges lining the outside.
Which of the following are characteristics of neurons
Conductivity amitotic secretions excitability extreme longevity
The electrical gradient in a resting neuron it's such that the_______ of the cell is negative relative to the_________.
Inside Outside
Repolarization is due to the opening of voltage-gated ________ And the subsequent movement of the _________ out of the cell
K+, K+
anterograde axonal transport
Movement of nutrients in a neuron away from the cell body distally to axon termination
retrograde axonal transport
Movement of used or worn out materials from distal areas to cell body
Many excitatory neurotransmitters caused the opening of channels that allow for the flow of
Na+ and k+
Which of the following pumps can you find in the plasma membrane?
Na+, K+, Ca2+
Voltage is a measure of relative_______ energy
Potential
Graded potentials are produced within the _____ segment or a neuron.
Receptive
Flow of the __________ ion is the most common cause of depolarization
Sodium
The two factors that affect PNS regeneration are
The amount of damage and the distance between injury and the effector organ
The myelin sheath covers_______.
The axon
If demyelination occurs, why don't action potentials occur at regions of the axon that were previously myelinated?
These regions lack the appropriate concentration of voltage-gated sodium channels.
In retrograde transport, substances are moved______ the cell body
Toward
A synapse is a junction between
a neuron and another cell
The nerve impulse causes _______ in the number of calcium ions that enter the synaptic knob
an increase
Which glial cell occupies the space of dying neurons
astrocytes
Cytoplasm within an axon is called
axoplasm
The central nervous system is made up of the
brain and spinal cord
components of the central nervous system
brain and spinal cord
Most synapses in the Human body are
chemical synapses
The total length of the axon is called the ______ segment
conductive
The main activity of the ______ is the propagation of an action potential along the axolemma.
conductive segment
demyelinating diseases cause a ______ And the conduction velocity of action potentials.
decrease
A positive change in the membrane potential is called
depolarization
Glial cells _____ transmit electrical impulses
do not
Creating and transmitting ___________ currents is central to the function of neuron physiology
electrical
A difference in the number of charged particles between two sides of the membrane forms a
electrical gradient
______ is responsiveness to stimuli.
excitability
Action potentials occur
in the unmyelinated regions of an axon
When voltage-gated sodium channels are open, sodium flows _____________ the neuron making the inside of the cell more _______________.
into; positive
graded potentials result from the opening of
ligand-gated channels
A myelin sheath is made of a high percentage of
lipids
If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron.
multipolar
Most motor neurons are
multipolar
The presence of a ______ sheath increases the rate of impulse conduction.
myelin
A cablelike bundle of axons in the peripheral nervous system is called a ______.
nerve
What is the primary tissue of the nervous system?
nervous tissue
Nervous tissue is composed of glial cells and
neurons
The functions of astrocytes are to
- help form the blood-brain barrier - assist neuronal development - regulate the composition of the interstitial fluid