Nervous System I: Ion Channels - Self Test
NOTE: This quiz is designed to be completed using the InteractivePhysiology CD that you used in the Muscle Lab. However, you should be able to answer most of the questions without the CD by using your class notes and your textbook.
1. What kinds of structures in the cell membrane function as ion channels?
Integral Membrane Proteins form ion channels
2. Ion channels are selective for specific ions. What three
characteristics of
the ions are important for this selectivity?
a. Charge
b. Size
c. How much water the ion holds around it
3. Channels can be classified as either active or passive channels. A
sodium channel
that is always open would be classified as a/an ___passive
(leak)_______
channel.
4. Would sodium ions move into or out of the neuron through the channels in question 3? __into_____________
5. Voltage-gated potassium channels open at what voltage? __~ +30____ mV
6. Acetylcholine (ACh) and GABA are neurotransmitters that open
chemically-gated
channels. What ions pass into the cell when these channels are activated?
a. ACh: _______Na+_________________ ions
b. GABA: _______Cl-_________________ ions
7. Ion channels are regionally located and functionally unique. List all the areas on the neuron and the type of potential dependent on the following types of ion channels:
a. Passive (leak) channels - dendrites, cell body; resting membrane potential, action potential
b. Chemically-gated channels - dendrites, cell body; graded potentials, action potentials
c. Voltage-gated channels - axons; action potential
8. From the quiz, place an "X" by the characteristics of voltage-gated sodium channels.
Always open
X Found along the axon
X Important for action potential
X Opened and closed by gates
Found on the dendrites and cell bodies
Important for resting membrane potential
9. Name two types of channels (active or passive) through which chloride ions could pass into the cell.
a. Passive Cl- channels
b. Ligand-gated (GABA)