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Nervous System I + II OBSR Part 1
Nervous System I + II OBSR Class 3 Part 1 (Neurons and Action Potentials)
119
Biology
Undergraduate 2
03/02/2011
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Term
__________ is when the nervous system identifies and response to a stimuli.
 Definition
1) Irritability
Term
The endocrine system uses __________ signals to coordinate a __________, __________-term response.
 Definition
1) Chemical
2) Slower
3) Long
Term
The four basic processes involved in neuronal signaling are:
 Definition
1) Reception
2) Transmission
3) Integration
4) Response
Term
__________ are specialized for receiving and transmitting electrical signals.
 Definition
1) Neurons
Term
__________ can be further classified by the direction in which they transfer information.
 Definition
1) Neurons
Term
The three primary neuron types are:
 Definition
1) Sensory (afferent) neurons
2) Inter neurons
3) Motor (efferent) neurons
Term
__________ can be classified by the number of extensions they have.
 Definition
1) Neurons
Term
__________ can also be classified by location, neurotransmitter used, etc.
 Definition
1) Neurons
Term
__________ __________ support and protect the neurons and carry out many regulatory functions.
 Definition
1) Glial cells
Term
The five different classifications glial cells can be grouped into are:
 Definition
1) Astrocytes
2) Microglia
3) Oligodendrocytes
4) Schwann cells
5) Ependymal cells
Term

Neural Pathway

1. __________ (comes from environment)

2. Receptor

3. __________ __________ (type of neuron)

4. __________ (type of neuron)

5. __________ __________ (type of neuron)

 6. __________ __________ (last place signal is brought)

7. Response

 Definition
1) Stimulus 2) Sensory neuron 3) Interneuron 4) Motor neuron 5) Effector organ
Term
__________ neurons transmit information from the sensory organs to the CNS and are also known as __________ neurons.
 Definition
1) Sensory
2) Afferent
Term
__________ neurons transmit information from the CNS to the effector organs (muscles or glands) and are also known as __________ neurons.
 Definition
1) Motor 2) Efferent
Term
__________ neurons link between sensory and motor neurons and are found in the CNS are also known as __________ neurons.
 Definition
1) Interneurons
2) Assocation
Term
The __________ __________ contains the nucleus, bulk of the cytoplasm, most of the organelles, and integrates incoming signals.
 Definition
1) Cell body
Term
__________ are short, highly branched cytoplasmic extension specialized to receive stimuli and send signals to the cell body.
 Definition
1) Dendrites
Term
An __________ is a singly, thin but long cytoplasmic extension of the neuron projection from opposite ends of the dendrite which conducts nerve impulses away from the cell body to another neuron or an effector and ends in a synaptic terminal.
 Definition
1) Axon
Term
A __________ is a junction between a synaptic terminal of one axon and another neuron or effector.
 Definition
1) Synapse
Term
The cell body contains the __________, the bulk of the __________, most of the __________ and integrates incoming signals.
 Definition
1) Nucleus
2) Cytoplasm
3) Organelles
Term
Dendrites are __________, __________ branched cytoplasmic extensions specialized to receive __________ and send signals to the __________ __________.
 Definition
1) Short
2) Highly
3) Stimuli
4) Cell body
Term
The axon is a single, thin, but long cytoplasmic extension of the neuron projecting from the opposite end of the __________; conducts nerve impulses __________ (direction) from the cell body to another neuron or effector and ends in a __________ __________.
 Definition
1) Dendrite 2) Away 3) Synaptic terminal
Term
__________ __________ is an insulation which allows information to travel more efficiently, or faster, so that the material does not "leak out."
 Definition
1) Myelin sheath
Term
__________ __________ are a type of glial cells in the PNS that form an insulating covering called __________ __________ which is a white, fatty material.
 Definition
1) Schwann cells
2) Myelin sheath
Term
__________ are the glial cell in the CNS that form the myelin sheath.
 Definition
1) Oligodendrocytes
Term
Gaps in the myelin sheath are referred to as __________ __________ __________ where the __________ is not insulated with myelin.
 Definition
1) Nodes of Ranvier
2) Axon
Term
The primary difference between oligodendrytes and schwann cells is that oligodendrytes wrap around the neuron from a __________ __________ while the schwann cells utilize themselves to wrap around the cells.
 Definition
1) Remote area
Term
Looking at the structure of a neuron which part of the neuron do you believe needs to be myelinated?
a. Dendrites
b. Axon
c. Cell body
d. Synaptic terminals
 Definition
1) b. Axon
Term
Which type of glial cell is involved in memory and learning?
 Definition
1) Astrocytes
Term
Which type of glial cell physically supports neurons?
 Definition
1) Astrocytes
Term
Which type of glial cell provides neurons with nutrients?
 Definition
1) Astrocytes
Term
Which type of glial cell removes excess K+, which helps regulate composition of extracellular fluid in the CNS?
 Definition
1) Astrocytes
Term
Which type of glial cell induces blood vessels to form the blood-brain barrier?
 Definition
1) Astrocytes
Term
Which type of glial cell secretes growth factors?
 Definition
1) Microglia
Term
Which type of glial cell conducts phagocytosis of bacteria?
 Definition
1) Microglia
Term
Which type of glial cell forms the myelin sheath around neruons in the CNS?
 Definition
1) Oligodendrocytes
Term
Which type of glial cell lines the cavities of the CNS?
 Definition
1) Ependymal cells
Term
Which type of glial cell helps produce cerebrospianl fluid?
 Definition
1) Ependymal cells
Term
Which type of glial cell functions as neural stem cells?
 Definition
1) Ependymal cells
Term
Glial cells comprise __________ of the nerve tissue (only __________ of neurons).
 Definition
1) 90%
2) 10%
Term
__________ __________ is a neurological disorder which affects myelination and also results in muscular or motor retardation.
 Definition
1) Multiple sclerosis
Term
A nerve consists of bundles of axons held together by __________ tissue. The cell bodies belonging to the axons of a nerve are grouped in a __________.
 Definition
1) Connective
2) Ganglion
Term
What makes grey matter?
 Definition
1) Unmyelinated cell bodies, dendrites, etc.
Term
What makes white matter?
 Definition
1) Myelinated axons
Term
Dendrites are usually:
a. Long and unbranched
b. Long and highly branched
c. Short and unbranched
d. Short and highly branched
e. Myelinated
 Definition
1) d. Short and unbranched
Term
Most of the organelles in the neuron are in the:
a. Cell body
b. Dendrites
c. Axon
d. Myelin sheath
e. Synaptic terminals
 Definition
1) a. Cell body
Term
Myelination in the CNS is through __________ while in the PNS it is through __________ __________.
 Definition
1) Oligodendrocytes
2) Schwann cells
Term
TRUE or FALSE:
Interneurons are responsible for neural integration.
 Definition
1) True
Term
The voltage measured across the plasma membrane is called the __________ __________.
 Definition
1) Membrane potential
Term
Neurons are __________ cells and use __________ __________ to transmit information.
 Definition
1) Excitable
2) Electrical signals
Term
Two main factors determine the magnitude of membrane potential:
1. Differences in the concentrations between specific __________ inside the cells and those in the extracellular fluid.
2. Selective permeability of the __________ __________ to these ions.
 Definition
1) Ions
2) Plasma membrane
Term
The four primary states of a neuron are:
1. __________ (polarized)
2. __________ (action potential generation)
3. __________
4. __________
 Definition
1) Resting
2) Depolarizing
3) Repolarizing
4) Hyperpolarizing
Term
At rest, the membrane potential of Na+ is 10x greater __________ the cell than it is __________ the cell.
 Definition
1) Within
2) Outside
Term
At rest, the membrane potential of K+ is 10x greater __________ the cell than it is __________ the cell.
 Definition
1) Outside
2) Within
Term
At rest, the membrane potential of Cl is higher __________ the cell than it is __________ the cell.
 Definition
1) Within
2) Outside
Term
At rest, (not excited) the voltage difference across the plasma membrane is __________.
 Definition
1) -70mV
Term
At rest, the __________ concentration inside is greater than outside (about 10x).
 Definition
1) Potassium
Term
At rest, __________ concentration outside is greater than inside (10x)
 Definition
1) Sodium
Term
At rest, the plasma membrane is up to 100 times as permeable to __________ as to __________.
 Definition
1) K+
2) Na+
Term
At rest, __________ pumped out of the neuron cannot easily pass back into the cell while __________ pumped into the neuron can easily diffuse out.
 Definition
1) Na+
2) K+
Term
Concept of Equilibrium Potential
1. __________ diffuses out of cell.
2. Increase in __________ charge outside.
3. Results in electrical gradient
4. Forces some of __________ ions from outside to inside.
 Definition
1) K+
2) Positive
3) K+
Term
The __________ __________ __________ __________ is when the membrane potential at which the force of the electrical gradient equals the force of the chemical gradient (no net movement of ion)
 Definition
1) Equilibrium Potential for K+
Term
Na+ and K+ move through passive ion channels through __________ _________ (down the concentration gradient).
 Definition
1) Facilitated diffusion
Term
Sodium Channels
1. In the resting state, voltage-gated __________ channels are __________.
2. When the voltage reaches __________ __________, activation gates __________ quickly, allowing Na+ to pass into the cell.
3. After a certain time, inactivation gates __________, blocking the channels.
4. __________ gates are open when a neuron is in the resting state; they close __________ in response to depolarization.
5. The __________ channel is open only during the brief period when both activation and inactivation gates are __________.
 Definition
1) Na+
2) Closed
3) Threshold level
4) Open
5) Close
6) Inactivation
7) Slowly
8) Ion
9) Open
Term
Potassium Channels
1. Voltage-gated __________ channels have activation gates that __________ slowly in response to __________.
2. These channels have no __________ gates.
 Definition
1) K+
2) Open
3) Depolarization
4) Inactivation
Term
Na+ channels open __________ and close __________ after some delay.
 Definition
1) Fast
2) Slowly
Term
K+ channels open and close __________.
 Definition
1) Slowly
Term
A stimulus can alter the resting potential by increasing the membrane's permeability to __________ which moves into the cell by __________ __________ to increase the voltage (__________ negative)
 Definition
1) Na+
2) Facilitated diffusion
3) Less
Term
When voltage reaches a certain critical point (threshold potential - __________ mV) an __________ __________ is generated
 Definition
1) -55
2) Action potential
Term
At resting state, voltage-activated Na+ and K+ channels are __________.
 Definition
1) Closed
Term
At depolarization (threshold), the voltage-activated Na+ channels __________, and Na+ entering the neuron cause further __________.
The __________ __________ is generated.
 Definition
1) Open
2) Depolarization
3) Action potential
Term
At repolarization, voltage-activated Na+ channels __________; voltage-activated K+ channels are __________; __________ diffuses out of cell, restoring negative charge to inside of the cell.
 Definition
1) Close 2) Open 3) K+ 
Term
At the return to resting state, voltage-activated Na+ and K+ channels __________.
 Definition
1) Close
Term
In the beginning of depolarization, the voltage reaches __________mV.
 Definition
1) -55
Term
During depolarization, __________ voltage-gated ion channels __________ and __________ rush into the cell (__________ feedback mechanism).
 Definition
1) Na+
2) Open
3) Na+
4) Positive
Term
During depolarization, membrane permeability to Na+ __________.
 Definition
1) Increases
Term
During depolarization, inactivation gates that are __________ in the resting neuron __________ slowly in response to depolarization.
 Definition
1) Open
2) Close
Term
During depolarization, __________ can pass through the channel only during the brief period where both activation and inactivation gates are __________.
 Definition

1) Na+

2) Closed
Term
At the conclusion of depolarization, inactivation gates __________ completely, with a resulting membrane potential of about __________ mV.
 Definition
1) Close
2) +35
Term
During repolarization, voltage-gated K+ channels slowly __________ in response to depolarization and K+ rushes __________ (direction) the cell.
 Definition
1) Open 2) Out
Term
During repolarization, voltage-activated K+ channels remain __________ until the resting potential has been restored.
 Definition
1) Open
Term
During hyperpolarization, K+ channels remain __________ with Na+ channels __________ even as resting membrane potential is reached leading to an undershoot until K+ channels are __________ and membrane potential returns to rest.
This undershoot allows the __________ channels to return to their resting state.
 Definition
1) Open
2) Closed
3) Closed
4) Na+
Term
At the conclusion of hyperpolarization, voltage-gated Na+ channels are __________; however, Na+ inactivation gates are __________ and Na+ channels are available if another stimulus is applied.
 Definition
1) Closed 2) Open
Term
At the conclusion of an action potential, __________ prevents the neuron from receiving another stimulus during this time (or at least raises the threshold for any new stimulus).
 Definition
1) Hyperpolarization
Term
Part of the importance of __________ is in preventing any stimulus already sent up an axon from triggering another action potential in the opposite direction.
 Definition
1) Hyperpolarization
Term
__________ assures that the action potential is proceeding in one direction.
 Definition
1) Hyperpolarization
Term
A __________ __________ permits the measurement of the flow of ions through a single channel.
 Definition
1) Patch clamp
Term
Which of the following best explains a change in voltage in an axon from +25mV to 0mV?
a. Facilitated diffusion of sodium ions out of the axon
b. Facilitated diffusion of sodium ions into the axon
c. Facilitated diffusion of potassium ions out of the axon
d. Facilitated diffusion of potassium ions into the axon
e. Pumping of sodium and potassium ions
 Definition
1) c. Facilitated diffusion of potassium ions out of the axon (review repolarization).
Term
The size of the stimulus determines
a. The size of the action potential
b. The frequency of the action potential
 Definition
1) b. The frequency of the action potential
Term
TRUE or FALSE:
In order to maintain a resting membrane potential you need a continuous supply of ATP.
 Definition
1) True
Term
At resting state, the membrane is most permeable to which ion:
a. Na+
b. K+
c. Cl-
 Definition
1) b. K+
Term
At resting state, this ion has a higher intracellular concentration to extracellular concentration
a. Na+
b. K+
c. Cl-
 Definition
1) b. K+
Term
TRUE or FALSE:
At action potential peak there is a slight excess of negative ions on the inside compared to the outside of the cell.
 Definition
1) False
Term
TRUE or FALSE:
Is a nerve impulse faster than electrical transmission in a wire?
 Definition
1) False
Term
YES or NO:
During an action potential, do you expect the concentration of large anions to change?
 Definition
1) Yes
Term
YES or NO:
Maintenance of resting potential requires a continuous supply of ATP.
 Definition
1) Yes
Term
An action potential is best classified as an __________ __________ __________ response.
Action potentials can also be classified as __________-__________.
 Definition
1) All-or-nothing
2) Self-propagating
Term
An __________ __________ __________ is when a second response is not possible regardless of strength or duration of a stimulus due to unrecovered state of Na+ channels.
 Definition
1) Absolute refractory period
Term
A __________ __________ __________ is when a second response can be elicited but at a greater "cost;" since some Na+ channels are now in a resting state and K+ channels are still open, it provides the opportunity for a second response (membrane is __________).
 Definition
1) Relative refractory period
2) Hyperpolarized
Term
A __________ conduction of an action potential occurs in unmyelinated axons.
 Definition
1) Continous
Term
A __________ conduction of an action potential often exhibits smooth propagation.
 Definition
1) Continous
Term
A __________ conduction of an action potential has speed proportional to the diameter of the axon (1-10m/s).
 Definition
1) Continous
Term
A __________ conduction of an action potential occurs in myelinated axons.
 Definition
1) Saltatory
Term
A __________ conduction of an action potential jumps from one Node of Ranvier to the next.
 Definition
1) Saltatory
Term
A __________ conduction of an action potential occurs only in vertebrates and has a speed of about 120m/s.
 Definition
1) Saltatory
Term
A __________ __________ is a local response that functions as a signal only over a very short distance, because it fades out within a few millimeters of its point of origin.
 Definition
1) Graded potential
Term
A graded potential varies in __________; that is, the potential charge varies depending on the __________ of the stimulus applied.
 Definition
1) Magnitude
2) Strength
Term
In a __________ __________, the larger the stimulus is, the larger the change in permeability and the greater the change in membrane potential.
 Definition

1) Graded potential

2) Permeability
Term
A __________ __________ is a gap between two cells.
 Definition
1) Gap junction
Term
Neurons communicating through __________ __________ utilize ions and small molecules through gap junctions to reach one another.
 Definition
1) Electrical synapses
Term
Neurons communicating through __________ __________ utilizes chemical messengers from a secretory cell to reach the target cell.
 Definition
1) Chemical synapses
Term

Neural Impulses Transmitted Across a Synapse

1. Action potential reaches synaptic terminals at the end of the presynaptic neuron.

2. __________ channels open in the membrane, all __________ from extracellular fluid to enter the synaptic terminal.

3. Ca2+ cause __________ __________ to fuse with plasma membrane and release neurotransmitters into synaptic cleft.

4. __________ binds with receptors on membrane of postsynaptic neuron.

5. In response to these actions, specific ion channels open or close, resulting in either depolarization or hyperpolarization. When __________ reaches threshold level, action potential is generated in postsynaptic neuron.

 Definition
1) Ca2+ 2) Ca2+ 3) Synaptic vesicles 4) Neurotransmitter 5) Depolarization
Term
__________ __________-__________ __________ (EPSP) bring the neuron closer to firing.
 Definition
1) Excitatory post-synaptic potential
Term
__________ __________-__________ __________ (IPSP) move the neuron farther away from its firing level.
 Definition
1) Inhibitory post-synaptic potential
Term
EPSPs and IPSPs are produced continuously in all __________ neurons and are __________ __________.
 Definition
1) Post-synaptic
2) Graded responses
Term
__________ __________ is the process of summing or integrating incoming signals.
 Definition
1) Neural integration
Term
Summation can be either __________ or __________.
 Definition
1) Temporal
2) Spatial
Term
In __________ of neural input, several presynaptic neurons synapse with one postsynaptic neuron.
 Definition
1) Convergence
Term
In __________ of neural output, a single presynaptic neuron synapses with many postsynaptic neurons.
 Definition
1) Divergence 
Term
Trends in Nervous System Evolution
1. Increased number of __________ __________
2. Concentration of nerve cells
3. Specialization of function
4. Increased number of __________ and more complex synapses
5. __________
 Definition
1) Nerve cells
2) Interneurons
3) Cephalization
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