|
|
Every 10 seconds, a person in the United States goes to the emergency room complaining of head pain. About 1.2 million visits are for acute migraine attacks.
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 60,000 miles of blood vessels in every adult human.
During the twentieth century, a variant of the metric system was used in Russia and France in which the base unit of mass was the tonne. Instead of kilograms, this system used millitonnes (mt).
It is believed that the Incas used anesthesia. Evidence supports the theory that shamans chewed cocoa leaves and drilled holes into the heads of patients (letting evil spirits escape), spitting into the wounds they made. The mixture of cocaine, saliva, and resin numbed the site enough to allow hours of drilling.
![Glioma. (a) Illustration of a large glioma (colored area) within the left cerebral hemisphere in a s](https://biology-forums.com/gallery/47/medium_14755_14_10_12_6_48_57_94081413.jpeg)
![Endocarditis. The human heart has been sectioned to reveal the left ventricle and origin of the aort](https://biology-forums.com/gallery/47/medium_14755_11_11_12_7_14_26_100221543.jpeg)