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.
22 Helpful Votes. A. For females, the reference range for BUN is 7-24 mg/dL. For Creatinine the reference range is 0.5-1.0 mg/dL. The opinions expressed here are solely those of the User. The opinions expressed here are solely those of the User.User-generated content areas are not reviewed by a WebMD physician.