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;
44 Cards in this Set
- Front
- Back
|
What are the 2 categories of ion channels, and are they usually opened or closed?
|
nongated: usually open gated: open or closed |
|
|
What type of channel is a "Leak channel"? |
non-gated ex: sodium and potassium channels |
|
|
What is an allosteric channel, and which category is it? |
A channel that can exist in more than one open or closed state These are gated channels |
|
|
What provides the energy for gating? |
changes in electrical potential |
|
|
What are three types of gated channels? |
voltage gated ligand gated mechanically gated |
|
|
which type of channel opens/closes in response to changes in membrane potential? |
voltage-gated |
|
|
What are the 3 possible states of voltage-gated channels? |
resting- channel is closed but can be opened, inactivation gate is open active- channel is open refractory- inactivation gate is closed |
|
|
How many genes encode sodium channels? |
10 genes |
|
|
How many domains does a sodium channel have? |
4 domains |
|
|
How many alpha- helixes transverse the membrane in each domain of a sodium channel? |
6 alpha helices |
|
|
A pore loop in a sodium channel is formed between which two alpha helixes? |
S5 and S6 |
|
|
What is the voltage-dependent portion of the sodium channel? |
S4 |
|
|
What is membrane potential (Vm)? |
the electrical potential difference across the neuronal membrane at any time |
|
|
What does the Nernst equation tell you? |
The equilibrium potential of any ion present on the sides of the membrane that is permeable to that ion. |
|
|
What does the Goldman Equation tell you? |
Used to calculate the neuronal membrane potential when the membrane is permeable to more than one ion. |
|
|
Which side of the neuronal membrane is more negative during resting potential? |
the inside of the cell (cytosol side) |
|
|
What is the stage at which enough voltage-gated sodium channels are open and sodium permeability is greater than potassium? |
Threshold potential |
|
|
What is the name of a mini version of a voltage clamp? |
Patch clamp |
|
|
What is an EPSP? |
Excitatory post-synaptic potential depolarization of post synaptic membrane by the action of a synaptically released neurotransmitter |
|
|
What are two examples of neurotransmitters that cause EPSP? |
Acetylcholine and glutamate |
|
|
What is EPSP integration? |
EPSP's add together to produce significant postsynaptic depolarization |
|
|
What is spatial summation? |
EPSP is generated simultaneously at different spaces |
|
|
What is temporal summation? |
EPSP is generated at the same synapse in rapid succession. |
|
|
What is synaptic integration? |
The process by which multiple synaptic potentials combine with one post synaptic neuron. |
|
|
What causes hyper polarization? |
Slow closing of potassium channels, so excess potassium leaving the cell, or chloride entering. |
|
|
What is an IPSP? |
Inhibitory Postsynaptic potential: hyperpolarization in postsynaptic membrane potential by action of synaptically released neurotransmitter |
|
|
What are 2 examples of neurotransmitters that cause IPSP? |
Glycine and GABA |
|
|
What are 3 examples of things that can block sodium channels? |
1. tetradotoxin: clogs sodium pore 2. saxitoxin: 3. aconitine: (buttercups) inactivates channels |
|
|
Depolarization of presynaptic nerve causes what channel to open/ what to enter? |
calcium |
|
|
Increase in intracellular levels of calcium cause what to happen? |
Release of neurotransmitter |
|
|
Voltage gated calcium channels are blocked by what? |
several divalent ions: Mn2+, Ni2+, Cd2+... |
|
|
How many polypeptides does a potassium channel have? |
4 |
|
|
Which "S" is the activation gate for voltage- gated potassium channels? |
S4 |
|
|
What are 3 things that block voltage-gated potassium channels? |
tetraethylammonium (TEA) Cs2+ Ba2+ |
|
|
What are 2 ways that second messengers open channels? |
direct binding, causing a conformational change indirect phosphorylation of channel proteins |
|
|
What are TRP channels? What are they regulated by? |
Transient receptor potential channel Regulated by lipid messengers, protons, and temperature |
|
|
What do TRP channels do? |
Conduct calcium into cells in response to activated GPCR |
|
|
Increasing axon diameter causes what change to the resistance to flow of charge? |
less resistance to flow of charge |
|
|
What is saltatory conduction? |
The jumping of action potential from one node to the next. |
|
|
What is Lambert- Eaton Syndrome? What causes it and how is it treated? |
Loss of voltage-gated Ca2+ channels on presynaptic terminal, less Calcium enters, reduces neurotransmitter release, causing muscle weakness, dry mouth, and dizziness. Treated by steroids and plasmaphoresis |
|
|
What is myasthenia Gravis? How is it treated? |
decreased number of working nicotinic acetylcholine receptors on postsynaptic membrane due to T-cells binding to receptor. Causes muscle weakness, decreased muscle response to acetylcholine. Treated with Acetylcholinesterase, thymus removal |
|
|
What is Guillain-Barre Syndrome? |
axonal demyelination of PNS, slows conduction of action potential in CNS, causes muscle weakness, lack of coordination, speech and vision problems. |
|
|
What is the cause of multiple sclerosis and what are the symptoms? |
Demyelination of axons in CNS. Conduction of action potentials down the axon is slowed. Causes muscle weakness, lack of coordination, speech and vision disturbances. |
|
|
What is the cause of cystic fibrosis, and what are treatment options? |
A mutated CFTR gene, causing impaired chloride channels. Cl- can't be exported from lungs, causing thick mucous. Treatment options: antibiotics, bronchodilators, steroids |
