The familiar sounds of your heart are made by the heart's valves as they open and close.
Did you know?
According to the CDC, approximately 31.7% of the U.S. population has high low-density lipoprotein (LDL) or "bad cholesterol" levels.
Did you know?
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Did you know?
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
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In 1864, the first barbiturate (barbituric acid) was synthesized.
Elephants in use by Indian cavalry
cell signaling cytoplasmic response
Spatial and Response Strategies
Major Indian Cultures, AD 1–1500
Frequency distribution curve: interpatient variability in drug response.
Regulatory effects of the vascular endothelium in normal and pathologic states