What did I learn? Score Your Quiz (Module 3) – The Alcohol Pharmacology Education Partnership

Why are there are so many dendrites associated with each neuron cell body?
1. The branch-like structure keeps the neurons from crowding together.
  Sorry, try again. It’s OK if neurons are crowded together. The branch-like structure increases the surface area for synapses and communication between neurons.
2. The branch-like structure increases the surface area for synapses and communication between neurons.
  That’s right! The branch-like structure increases the surface area for synapses and communication between neurons.
3. The more dendrites there are, the more surface area for myelin to cover.
  Sorry, that is incorrect. Myelin only surrounds the axon, where the major electrical impulse (action potential) travels. The branch-like structure increases the surface area for synapses and communication between neurons.
4. The more dendrites there are, the greater the chance of receiving information from neighboring neurons.
  You’re close, but that’s not quite right. The branch-like structure increases the surface area for synapses and communication between neurons.
Why do neurons use both electrical and chemical signals to communicate with each other?
1. Electrical signals can’t jump across the synaptic space.
  Great! Electrical signals travel down the axon to the terminal, but can’t cross the synaptic space. Instead, the electrical impulse triggers a chemical to be released and carry the message across to another neuron.
2. Neurons need fast and slow ways to pass information between them.
  Not quite. There are fast and slow ways for neurons to communicate, but that is not the reason. Electrical signals travel down the axon to the terminal, but can’t cross the synaptic space. Instead, the electrical impulse triggers a chemical to be released and carry the message across to another neuron.
3. Neurons need chemical signals to stop the electrical signals.
  Incorrect. The chemical signals cause new electrical signals in the receiving neuron. The problem is that the electrical signals that reach the terminal can’t jump cross the synaptic space.
4. Electrical signals can degrade over the distance of an axon.
  Sorry, that is incorrect. The electrical signal doesn’t degrade. Once it reaches the axon’s terminal it stops because it can’t cross the synaptic space. Instead, the electrical impulse triggers a chemical to be released and carry the message across to another neuron.
Alcohol causes blackouts or inability to recall certain events that occurred earlier when one was drinking alcohol. What could explain the production of the blackout?
1. Alcohol damages cells in the hippocampus.
  Not quite right. Alcohol does damage the hippocampus, but this occurs over a period of time. The memory loss during a blackout is immediate.
2. Alcohol increases electrical impulses in the hippocampus.
  Sorry, try again. Alcohol reduces electrical firing of neurons in the hippocampus responsible for setting the initial stages of memory. So, events can’t be recalled later.
3. Alcohol decreases electrical impulses in the hippocampus.
  That’s right! Alcohol reduces electrical firing of neurons in the hippocampus responsible for setting the initial stages of memory. So, events can’t be recalled later.
4. Alcohol shrinks the hippocampus.
  Sorry, try again. Alcohol can shrink the hippocampus, but this occurs over a period of time. The memory loss during a blackout is immediate.
Alcohol can damage the hippocampus, an area of the brain involved in learning and memory. It actually causes the hippocampus to shrink. What could explain this?
1. Alcohol accelerates the stem cell cycle.
  Incorrect. Alcohol actually interrupts the cell cycle in phase G1 of neural stem cell growth, thereby decreasing neurogenesis.
2. Alcohol causes stem cell proliferation.
  Sorry, try again. Alcohol actually interrupts the cell cycle of neural stem cell growth, thereby decreasing proliferation of neural stem cells and neurogenesis.
3. Alcohol dehydrates the hippocampus.
  No. Alcohol can dehydrate the body in general by promoting “peeing,” but this doesn’t explain why the hippocampus shrinks. Alcohol interrupts the cell cycle of neural stem cell growth, thereby decreasing proliferation of neural stem cells and neurogenesis.
4. Alcohol decreases neurogenesis.
  Great! Alcohol decreases neurogenesis in the hippocampus either by preventing neural stem cell proliferation or promoting neural stem cell death.
Magnetic resonance imaging (MRI) is a technique that measures energy released when protons, the nucleus of H atoms, spin in an electromagnetic field. Why does the MRI focus in on protons?
1. Protons are abundant in the body; they are found in water and fat, which is most of us!
  Great! H atoms make up about 63% of the atoms in our bodies; they are abundant in water and fat. The sheer number provides an excellent signal for the MRI scanner to detect when they spin.
2. Protons spin at the right frequency to be detected by the MRI scanner.
  Incorrect. There’s a lot more to it! The reason is that H atoms make up about 63% of the atoms in our bodies; they are abundant in water and fat. The sheer number provides an excellent signal for the MRI scanner to detect when they spin.
3. Protons do not get destroyed by the magnetic field produced by the MRI scanner.
  Wrong answer. Protons don’t get destroyed by the scanner, but that’s not the reason. H atoms make up about 63% of the atoms in our bodies; they are abundant in water and fat. The sheer number provides an excellent signal for the MRI scanner to detect when they spin.
4. Protons are charged particles that are easily detected by the magnet in the MRI scanner.
  Sorry, you’re wrong. The magnet is not detecting the charge of the proton. The reason is that H atoms make up about 63% of the atoms in our bodies; they are abundant in water and fat. The sheer number provides an excellent signal for the MRI scanner to detect when they spin.