The humble syringe is really a tiny pump named after a flute
Strip away the needle and a syringe is simply a pump: a piston sliding inside a tube, pulling fluid in and pushing it out. Its name comes from the Greek syrinx, the panpipe. Versions of it have filled fountain pens, basted roasts, fought fires and, according to the Roman writer Celsus, treated patients 2,000 years ago.
The barrel is usually clear plastic or glass with printed volume marks. Glass versions can be sterilised in an autoclave, while plastic ones are cheap enough to throw away after a single use, which cuts the spread of blood-borne infections. Plastic designs come in two styles: three-part syringes use a rubber-tipped plunger, while two-part ones rely on a precisely fitted plastic piston, a style favoured in Europe because it avoids the silicone oil needed to lubricate rubber seals.
Details at the business end vary. A Luer lock twists a needle securely into place; a slip tip just pushes on; a longer tapered catheter tip can seal into tubing. Eccentric tips put the nozzle off to one side, letting the needle lie almost flat against the skin for reaching surface veins. Oral syringes, typically purple and without threaded tips, measure liquid medicines for squirting straight into a mouth.
Specialised designs abound. Insulin syringes are marked in units for standard U-100 insulin, meaning 100 units per millilitre, and have short needles because the injections go just under the skin. Dentists use breech-loading syringes that take sealed anaesthetic cartridges, a system Bayer Dental trademarked as the Carpule in 1928. During the COVID-19 pandemic, dose-sparing syringes that leave almost nothing in the barrel became popular because vaccine was scarce.
Outside medicine, laboratories use tiny glass syringes to inject a single microlitre into a gas chromatograph, or to move air-sensitive chemicals through rubber seals without exposure to oxygen. Cooks inject gravy or juices into meat and fillings into pastries, workshops squeeze glue into tight joints, and hand-reared baby mammals suckle from needleless ones. Large reciprocating pumps once used against fires were also called syringes.
Source: Syringe
