|
|
The familiar sounds of your heart are made by the heart's valves as they open and close.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
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.
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
Blood is approximately twice as thick as water because of the cells and other components found in it.