|
|
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
There are 20 feet of blood vessels in each square inch of human skin.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
Chronic necrotizing aspergillosis has a slowly progressive process that, unlike invasive aspergillosis, does not spread to other organ systems or the blood vessels. It most often affects middle-aged and elderly individuals, spreading to surrounding tissue in the lungs. The disease often does not respond to conventionally successful treatments, and requires individualized therapies in order to keep it from becoming life-threatening.
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.