Did your pulse change when standing? why do you think a change did or did not occur?

Explanation:

The pulse of the bodies raises for the first 20 seconds after sitting for a prolonged period of time and then to a standing position. It should, however, return to normal afterwards. The heartbeat of the body decreases because as you travel the blood needs to flow to the active areas and the blood flows downward from gravity, however you still need to pump blood to your brain. The rise in blood demand makes the heart pump more rapidly.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation: