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.
You might also like to view...
Civil commitment is the reason Hannah was hospitalized against her will. Which criterion could have been used in her civil commitment hearing?
a. her parents' fear that she was about to lose emotional control b. her inability to care for herself c. her inability to consult rationally with her attorney d. her diagnosis of antisocial personality disorder
A person starts from one point and comes up
with many different ideas or possibilities based on that point. The person is engaging in ________. a) functional thinking b) circular thinking c) convergent thinking d) divergent thinking
The division of our visual system into a visual perception track and a visual action track illustrates the concept of:
A. inattentional blindness. B. blindsight. C. dual processing. D. altered consciousness.
According to some research, a newborn who smiles at a smiling adult is engaging in
A. deferred imitation. B. invisible imitation. C. visible imitation. D. circular reaction.