For this telescope, the lenses are a concave convex (one side curved out and the other curved in) and a plano concave (one flat side and one side curved in). The plano concave lens is used as the eyepiece with the plano (flat) side facing the eye.
BUN redirects here. For other uses, see Bun (disambiguation). The liver produces urea in the urea cycle as a waste product of the digestion of protein. Normal human adult blood should contain between 6 and 20 mg of urea nitrogen per 100 ml (6â20 mg/dL) of blood.
What is Blood Urea Nitrogen (BUN)? Blood urea nitrogen (BUN) is a measure of the amount of urea in the blood . It provides useful information about your health. The liver produces urea as a waste product of the digestion of proteins (R, R). Urea is a safe vehicle to get rid of excess nitrogen from the body.