Week 3: Lectures 7-9 09/09/24-09/13/2024 Flashcards
What is the refractory period?
A period of time after the initiation of one action potential when it is impossible to initiate a second action potential no matter how much the cell is depolarized
What repolarizes a neuron?
A loss of positive charge
What does hyper polarize mean?
away from zero, more negative
What does depolarization mean?
more positive, toward zero
What can make a action potential faster?
If the length constant is large so threat the charge spreads far. It can increase the velocity and myelination.
What is the giant axon used for in the giant squid?
It is used for them to have a quicker reaction when being attacked. It sends the electrical impulses fast in order to send information for a faster reaction
What is something true about the membrane potential?
It does not change immediately when current flows because of the capacitative membrane
What determines the change in a membrane potential?
The time constant of the membrane will determine the time course for the change in membrane potential
What can make an action potential faster?
- If the length constant is large so that the charge spreads far
- Increase diameter in the axon
- Increase the membrane resistance
What are the node of ranvier?
the gaps between myelin that coats the axon
What is multiple sclerosis?
where your immune system attacks the myelin
What are ion channels?
Use concentration and electrical gradients. Are selective for specific ions K+, Na+, Ca2+, Cl-. Most are gated by specific signals. Chemical or electrical. Can be permeable to one or more ions but not common
What are some types of ligated ion-channels?
- neurotransmitters
- calcium activated potassium channels
- cyclic nucleotide gated channel
What are transporters?
Move ions or small molecules against their gradient. They require energy to move and pump solutes across membranes.
What is a function of transporters?
Critical for the creation and maintenance of ion concentration gradients
