 |
 Insulin
is a naturally-occurring hormone
secreted by areas within the pancreas known as
Islets of Langerhans. It is required by cells in
order for them to remove and use glucose from the
blood; glucose is what cells use to produce the
energy necessary to performance of their
functions. |
 William
Harvey proved that the heart, by repeated contractions, produces a
continuous stream of blood throughout the body
which continually returns to its source (the
heart). He also showed that the valves in the
veins always direct blood back to the heart. |
 Hearing
Man hears sounds when any vibrating
object pushes air molecules at a rate between 15
and 15,000 vibrations per second. Sound waves are
turned into nerve impulses inside the cochlea. |
