Syringe

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Syringe, device used to eject or collect fluids. A syringe consists of a hollow barrel made of glass, plastic, or metal with a close-fitting plunger or a rubber bulb on one end. The other end of the barrel has a nozzle which may be designed to accept a needle or other attachment. The barrel fills by suction when the plunger is pulled out, or when the bulb is compressed and subsequently allowed to inflate. Pushing in the plunger or squeezing the bulb forces the fluid out through the needle or nozzle.

Syringes come in many sizes and serve many purposes. The small syringe used in medicine to give hypodermic injections (forceful introduction of medication or fluid beneath the skin) has a plunger and a fine hollow needle. Its barrel is calibrated, featuring a set of equally spaced marks that measure the volume of its contents. The larger medical syringes used to cleanse wounds or body cavities, or to extract unwanted fluids from the body, have wider, flexible nozzles on one end and rubber bulbs on the other end.

Sharing unsterilized syringes can cause serious health problems. Human immunodeficiency virus (HIV), which may lead to acquired immunodeficiency syndrome (AIDS), has been spread by infected substance abusers who share the same syringe to inject intravenous drugs. The viruses that cause hepatitis A and hepatitis B, both of which inflame the liver, are also commonly transmitted through the use of shared needles and syringes.

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