Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
10 Cards in this Set
- Front
- Back
|
Increasing the diameter of an axon would increase or decrease the speed of conductance? Why?
|
Increase - bc increasing the diameter decreases the resistance.
|
|
|
How is the resistance of the membrane increased?
|
Myelination
|
|
|
A higher length constant = faster conduction. What two ways can the length constant be increased:
|
1. Increasing diameter of neuron
2. Increasing the axon membrane resistance via myelination. |
|
|
What are the 5 channels that he wants us to know:
|
1. Leaky K+ channel
2. Voltage gated Na+ channel 3. Voltage gated Ca2+ channel 4. Voltage gated K+ channel 5. Ca2+ dependent K+ channel |
|
|
What are the symptoms of Hyperkalemic period paralysis?
What causes it from a physiochemical perspective? What causes it genetically? |
1. Weakness and decreased muscle tone
2. Exercise or K-rich food result in muscle fibers unable to fire APs (cells are depolarized by 30-40 mV) 3. Mutation of muscle voltage-gated Na channels prevents some % from being completely inactive after depolarization resulting in small but constant inward current...inactivating normal Na channel and rendering muscle inexecitable (bc repolarization occurs v slowly). |
|
|
What is myotonia?
|
Difficulty getting muscle to relax once they have contracted.
|
|
|
What are symptoms of Thomsen's and Becker's disease?
|
Muscles of affected individuals relax unusually slowly following sudden contraction.
|
|
|
What is the problem in myotonic goats? Does it affect them in the CNS?
|
Mutation in Cl channel resulting in decreased conductance. It does not affect their CNS bc Cl channels are involved only in skeletal muscle.
|
|
|
Does Cl make it easier or harder to induce an action potential? Why?
|
Easier and action potential is maintained. Normally, Cl- will rush in to return the resting membrane potential but when channel is mutated or blocked, the elevated potential is left high and more APs are generated - i.e. myotonia.
|
|
|
Puffer fish block Na channels - does this result in a atonia or myotonia?
|
Atonia
|
