Insulin syringe

A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes it's actually a piston) that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the inside of the tube, allowing the syringe to take in and expel liquid or gas through a discharge at the front (open) end of the tube. The open end of the syringe may be fitted with a hypodermic needle, a nozzle or a tubing to help direct the flow into and out of the barrel. Syringes are frequently used in clinical medicine to administer injections, infuse intravenous therapy into the bloodstream, apply compounds such as glue or lubricant, and draw/measure liquids.

The word "syringe" is derived from the Greek σύριγξ (syrinx, meaning "tube") via back-formation of a new singular from its Greek-type plural "syringes" (σύριγγες).

Sectors in the syringe and needle market include disposable and safety syringes, injection pens, needleless injectors, insulin pumps, and specialty needles. Hypodermic syringes are used with hypodermic needles to inject liquid or gases into body tissues, or to remove from the body. Injecting of air into a blood vessel is hazardous, as it may cause an air embolism; preventing embolisms by removing air from the syringe is one of the reasons for the familiar image of holding a hypodermic syringe pointing upward, tapping it, and expelling a small amount of liquid before an injection into the bloodstream.

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