Chapter 12
The events of an EPSP in order
-The excitatory neurotransmitter binds to the chemically gated cation channel -More Na+ enters the postsynaptic cell then K+ leaves -inside of a cell becomes more positive -The local current Na+ becomes weaker as it moves towards the axon hillock
Membrane pumps require ________ energy
A lot of
Action potentials are always propagated along an axon at the same _______ but ________ can vary depending on the strength of the stimulus
Amplitude; frequency
The nerve impulse causes ________ in the number of the calcium ions that enter the synaptic knob
An increase
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
Astrocytes
A synapse is a junction _________.
Between a neuron and another cell
Many excitatory neurotransmitters cause the opening of channels that allow for the flow of ______.
Both Na+ and K+
Which are components of the central nervous system?
Brain and spinal cord
The presence of __________ ions causes the synaptic vesicles to bind to the membrane, allowing neurotransmitters to be released
Calcium
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
Another way for the neurotransmitter to be removed from the synaptic cleft by _________ where there is uptake by surrounding glial cells
Diffusion
Glial cells __________ transmit electrical impulses
Do not
Creating and transmitting ___________ currents is central to the function of neuron physiology
Electrical
Synapses are classified as __________.
Electrical and chemical synapses
A difference in the number of charged particles between two sides of the membrane forms a(n) ______________
Electrical gradient
What are characteristics of neurons?
Excitability, extreme longevity, conductivity, secretion, amitotic
True or false: a neuromodulator is another name for a neurotransmitter
False
A larger axon transmits an impulse _______ than a smaller axon
Faster
A potential there is a temporary change in membrane potential which lasts only as long as the stimulus that causes it in can vary in size is called a ________ potential.
Graded potential
The electrical gradient in a resting neuron is such that the ________ of the cell is negative relative to the _________.
Inside/outside
Neuronal pools are made of _________
Interneurons
The myelin sheath is made of a high percentage of __________.
Lipids
The brain interprets the increased frequency of nerve signals as a _________ stimulus
More intense
If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron.
Multipolar
___________ neurons are most common
Multipolar
Which pumps can you find in the plasma membrane?
Na+, K+, Ca2+
Which of the following membrane transporters are present throughout the membrane of a neuron?
Na+/K+ Pumps, Potassium leak channels, sodium leak channels
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
The ability to alter the response of neurons to neurotransmitters is known as _______.
Neuromodulation
Neuronal pools are also called _________
Neuronal pathways and neuronal circuits
Nervous tissue is composed of glial cells and _________.
Neurons
_______________ are released from neurons in response to conductive activity
Neurotransmitters
A nerve is part of the ___________ nervous system
Peripheral
Na+ and K+ leak channels and Na+/K+ pumps on the neuron are responsible for establishing and maintaining the _______ membrane __________.
Resting membrane potential
The function of a neuron is dependent on __________.
Resting membrane potentials changing
Removal of neurotransmitters from the synaptic cleft
Reuptake
Glial cells are ________ than neurons
Smaller
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 amount of damage and the distance between the injury site and the effector organ
The myelin sheath covers ____________.
The axon
In retrograde transport, substances are moved _________ the cell body.
Toward
True or false: Graded potentials vary in size depending on the stimulus
True
The measure of the difference in electrical charge between two areas is called a _________.
Voltage
If a subthreshold value is reached on an axon membrane, an action potential __________.
Will not occur.
