Exam 1 Flashcards
Which component of a neuron has a fixed diameter over its length?
Axon
In a neuron with open potassium channels but no potassium ions flowing across the membrane, which measure is NOT zero?
Ionic conductance
If there are open potassium channels in a neuron’s membrane but no potassium ions are flowing across the membrane, which measures are at zero?
Driving force & ionic current
At lecture we noted that Fragile X syndrome and General intellectual impairment both are associated with abnormalities in which neuronal component?
Dendritic spine
What are shared characteristics between rabies and herpes simplex virus infections?
- Retrograde axoplasmic transport
- Replication at the soma
- Transmission from an infected person or animal
What is NOT a characteristic shared between rabies and herpes simplex virus infections?
Occasional recurrence of symptoms at times of stress (only occurs in HSV)
Which type of cell myelinates neurons in the central nervous system?
Oligodendroglial cell
Conformational changes to tau protein are a key part of which disease?
Alzheimer’s disease
Which type of ion is more concentrated inside the neuronal membrane than outside?
Potassium (K+)
What happens to the equilibrium potential of a positively charged ion when its extracellular concentration is increased?
If the extracellular concentration of a positively charged ion is increased, its equilibrium potential will become more positive.
A cheeky banana-hating monkey wants to mess up the potassium in neurons. What would happen to the equilibrium potential for potassium if he simultaneously doubled the inside concentration and cut the outside concentration in half?
Ek would become more negative
Suppose you use an electrode in the soma to depolarize a neuron above threshold. You then depolarize the neuron even more. How does the added depolarization (i.e. taking Vm even further above threshold) alter the neuron’s response from the first depolarization?
The neuron will fire action potentials at a higher rate when the soma depolarization is increased
Which ion channel plays the LEAST role in action potentials?
Na-leak (Sodium leak channels)
When NaV (voltage-gated) channel becomes inactivated, what happens to the pore in the ion channel?
The pore in the ion channel becomes blocked
When John Pemberton, inventor of Coca Cola, weaned himself off of morphine, he discovered the local anesthetic properties of cocaine. When lidocaine (or cocaine) is injected into the skin, what is the primary mechanism by which it works on pain fibers as a local anesthetic?
Blocks sodium channels
In the relatively refractory portion of the action potential, what is the best description of what is happening to the conductances of the voltage-gated ion channels?
gNa (sodium conductance) is decreasing and gK (potassium conductance) is decreasing
After a neuron is depolarized and the membrane potential at the axon hillock changes from the resting potential, which is the EARLIEST time period in which sodium enters through voltage-gated sodium channels?
Resting potential to threshold
In order to improve his ability to catch mice by running at a blazingly fast speed, a clever cat named Tashi modifies his neurons for maximally fast propagation of action potentials, thus becoming ULTRA CAT! If he wants to make the fastest conduction of action potentials, he should use all the following EXCEPT
a) Myelination
b) Saltatory conduction
c) Shunting inhibition
d) Large diameter axons
Shunting inhibition
