Exam 1 Flashcards
What is the Sodium-Potassium pump? What does it do, how, and why?
maintains the membrane potential
The specific function of the sodium potassium pump is to move potassium ions into the cell and sodium ions out of the cell to drive an action potential. This creates a fluctuating concentration inside and outside of the cell causing the cell to pump more sodium and potassium in and out of the cell, resulting in depolarization and repolarization.
What are the steps in generation of Action Potential?
a. Draw and label the phases
b. Describe what is occurring during each phase
i. What channels are opening/closing
ii. How are ions moving (in/out)
LOOK AT STUDY GUIDE
What are the two types of post-synaptic potentials (PSP)?
Excitatory and Inhibitory post synaptic potential
What is spatial summation of PSP’s?
Example: ?????
Two different nuerons simultaneous stimuli at different location cause PSP that add together.
Spatial Summation PSPs?
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When would an action potential be generated?
When they fire and add together to reach threshold
Spatial Summation of PSP’s
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Describe an example when an action potential would not be generated?
Change in membrane potential can cancel each other out
What is Temporal Summation of PSP’s?
Same cell Two excitatory stimuli close in time cause EPSP’s that add together
Temporal Summation of PSP’s?
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Describe an example when an action potential would be generated?
Fire close to the same time from one cell to reach threshold
Temporal Summation of PSP’s?
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Describe an example when an action potential would NOT be generated?
Doesn’t fire close close therefore it wont reach threshold
Draw parts of the neuron: Soma, Dendrites, Axon, Hillock, Axon Collateral, Synapse
Three general types of neurons and what they do
Afferent: Sensory - dorsal root - sends signal to peripheral to cns
Efferent: Motor - Ventral root - sends signal from cns to pns
Interneuron: In CNS between afferent + efferent
Why is it good to have an axon with a large diameter?
It decreases resistance, therefore signal will travel down faster
Why is it bad to have an axon with a large diameter?
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Takes more myelination and more energy
Has a higher chance of a leakier membrane
What does myelination do?
It allows the charge to maintain longer and allows the signal to travel faster down the axon
Describe and compare saltatory conduction and continuous conduction along an axon?
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Saltatory conduction: Occurs in myelinated axons aka faster (jumps from node of ranvier) (voltage gated channels only at these nodes)
Continuous conduction: Unmyelinated axons aka slower (travels down the entire length of axon) (voltage gated channels Na found along the whole axon)
What cells are responsible for myenlination of neurons in the CNS and PNS?
Schwann cell for PNS
Oligodendrocytes for CNS
How does a chemical synapse work? Describe the steps for signal transmission.
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Picture
How does an electrical synapse work?
Gap junctions which allows ion to move in both directions (bidirectional)
Has a passive current flow and is extremely fast
What neurotransmitter is necessary for muscle fiber contraction?
Acetlycholine
The synapse between an alpha motor neuron and a muscle fiber is called
Neuromuscular junction
What neurotransmitter is released to result in a contraction of a muscle fiber
Acetylcholine
True or False: Demyelination can result in a conduction block
True
True or False: Paresthesias is not a system of demyelination
False
What is an example of Paresthesias
Are action potential occurring when they shouldn’t be. an example is a tremor or tingling
True or False : One way to fix a conduction block is to add Na+ channels between Nodes of Ranvier
True
What is the CNS?
Central nervous system; brain and spinal cord
What is an afferent?
Signal from the periphery toward the CNS
sensory signals
What is an efferent?
Signal from the CNS toward the periphery
Motor signals
What are two ways signals can be propagated
between neurons?
- Chemical via neurotransmitters
- Electrical via Gap junctions
………….are the myelinating cells in the CNS
Oligodendrocytes
………….are the myelinating cells in the PNS.
Schwann cells
What does myelinating an axon do?
Insulates leaky membrane =>
saltatory conduction
What is Gray matter?
Gray = neuronal cell bodies
What is White matter?
white = bundles of myelinated axons
What is a bundle of axons
called in the CNS?
tract
What is a bundle of axons
called in the PNS?
nerve
What is a collection of nerve cell
bodies called in the CNS?
nucleus
What is a collection of nerve cell
bodies called in the PNS?
ganglion
What kind of neurons send information through the
dorsal root in the spinal cord?
Sensory
What is in the dorsal root ganglion?
Soma (cell bodies) of
sensory neurons
What kind of neurons send their information through
the ventral root in the spinal cord?
Motor
Where are the motor Nueron cell bodies located
Ventral Horn
What is the difference between active and passive
transport of ions across a membrane?
Active moves against
concentration/electrical
gradients and requires
energy
Draw an action potential and label its parts and what ion channels are involved.
- Resting Potential – maintained by Na +/K+ pump
- Depolarization phase - Voltage-gated Na + channels open
- Repolarization phase - Voltage-gated K+ channels open; Na + channels close
- Undershoot - Voltage-gated K+ channels close, K+ diffuses across membrane (conc. Gradient)
- Draw an action potential and label its parts and what ion channels are involved.
Label Spinal Cord, Brain
46 Spinal Cord
What are the two types of post synaptic potential’s?
Excitatory and inhibitory postsynaptic potential
