Describe how the brain transports essential chemicals
What will be an ideal response?
The brain has several transport mechanisms. Small, uncharged molecules, including oxygen and carbon dioxide, cross freely. Water crosses through special protein channels in the wall of the endothelial cells. Also, molecules that dissolve in the fats of the membrane cross easily. Examples include vitamins A and D and all the drugs that affect the brain—from antidepressants and other psychiatric drugs to illegal drugs such as heroin. How fast a drug takes effect depends partly on how readily it dissolves in fats and therefore crosses the blood– brain barrier.
For a few other chemicals, the brain uses active transport, a protein-mediated process that expends energy to pump chemicals from the blood into the brain. Chemicals that are actively transported into the brain include glucose (the brain's main fuel), amino acids (the building blocks of proteins), purines, choline, a few vitamins, iron, and certain hormones.
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When a student does well on a test, she immediately takes the credit, saying that she did well because she studied hard or because she is a "brain."
When she does poorly, however, she blames the teacher for making up an "impossible" test or her roommates for interrupting her study. This student is demonstrating a. the fundamental attribution error. b. the Pygmalion effect. c. prejudice. d. the self-serving bias.
Being "in love" with someone as opposed to "loving" someone seems to require the experience of
a. passion. b. intimacy and commitment, but not passion. c. commitment only. d. intimacy only.