The following questions will help you review concepts presented in this module.

1. Why are there are so many dendrites associated with each neuron cell body?
   1. The branch-like structure keeps the neurons from crowding together.
   2. 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.
   4. The more dendrites there are, the greater the chance of receiving information from neighboring neurons.
2. Why do neurons use both electrical and chemical signals to communicate with each other?
   1. Electrical signals can’t jump across the synaptic space.
   2. Neurons need fast and slow ways to pass information between them.
   3. Neurons need chemical signals to stop the electrical signals.
   4. Electrical signals can degrade over the distance of an axon.
3. 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.
   2. Alcohol increases electrical impulses in the hippocampus.
   3. Alcohol decreases electrical impulses in the hippocampus.
   4. Alcohol shrinks the hippocampus.
4. 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.
   2. Alcohol causes stem cell proliferation.
   3. Alcohol dehydrates the hippocampus.
   4. Alcohol decreases neurogenesis.
5. 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!
   2. Protons spin at the right frequency to be detected by the MRI scanner.
   3. Protons do not get destroyed by the magnetic field produced by the MRI scanner.
   4. Protons are charged particles that are easily detected by the magnet in the MRI scanner.

Now, check your answers here.