The presence of a barrier between the blood stream and the brain is suggested by the observation that
A) all cells of the body are stained by a dye injected into the bloodstream.
B) injection of dye into the bloodstream stains all cells but those of the brain and spinal cord.
C) the gut is stained by a dye injected into the brain ventricles.
D) injection of dye into the ventricles stains all cells of the body.
E) most chemicals rapidly reach the brain after oral ingestion..
Answer: B
Rationale: The presence of a barrier between the blood stream and the brain is suggested by the observation that injection of dye into the bloodstream stains all cells but those of the brain and spinal cord.
You might also like to view...
Mrs. Hartley asked her second graders to draw a map of the school using their memory. The students' cognitive maps will probably
A) have an accurate arrangement. B) include landmarks. C) incorporate map symbols and a key. D) depict an organized route of travel.
Thirty-six subjects were used in a one-factor between-subjects experiment with three
levels of an independent variable. If the group sizes were equal, what is the value of N? a. 36 b. 12 c. 3 d. cannot tell from the information given