What connects the throat and the trachea?

Whats the difference between epinephrine and norepinephrine?

Which statement best illustrates that problem solving can create new medical devices? robert hooke was in charge of verifying the information that was sent to the royal academy. william harvey did experiments with apes to learn about the circulatory system. the stethoscope was invented because the physician did not want to put his head on women's chests to listen to their heart and lungs. anton van leeuwenhoek was a very curious man and looked at just about everything under this microscope.

Why would one lymph node in the neck be swollen and not the other? what causes them to swell?