| |
| | Heart - Wikipedia, the free encyclopedia |
 | | Amphibians and reptiles have a three-chambered heart, in which oxygenated blood from the lungs and de-oxygenated blood from the respiring tissues enters by separate atria, and is directed via a spiral valve to the appropriate vessel—aorta for oxygenated blood and pulmonary vein for deoxygenated blood. |
 | | The heart (Latin cor) is a hollow, muscular organ in vertebrates that pumps blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods. |
 | | In the human body, the heart is normally situated slightly to the left of the middle of the thorax, underneath the sternum (breastbone). |
| en.wikipedia.org /wiki/Heart (1914 words) |
|