|
|
Pubic lice (crabs) are usually spread through sexual contact. You cannot catch them by using a public toilet.
Your skin wrinkles if you stay in the bathtub a long time because the outermost layer of skin (which consists of dead keratin) swells when it absorbs water. It is tightly attached to the skin below it, so it compensates for the increased area by wrinkling. This happens to the hands and feet because they have the thickest layer of dead keratin cells.
Patients who cannot swallow may receive nutrition via a parenteral route—usually, a catheter is inserted through the chest into a large vein going into the heart.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.