What is syringe ? Explain essential use of it in our lives.

Syringe is a medical instrument used to take out blood from the body as well as to inject medicine inside the body. 

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 "Pan flute", "tube").Syringes are used in research labs for multiple tasks including injection of gases or liquids into chromatographs, chemical apparatus, or animals. Syringes can range from precision micro syringes to inexpensive disposable units.

The syringe works on the existence of atmospheric pressure. When the nozzle of a syringe is dipped in a liquid and its piston is withdrawn, the pressure inside the syringe is lower. The greater atmospheric pressure acting on the surface of the liquid pushes the liquid up into the syringe.The volume of gas sucked into a syringe during medication administration is orders of magnitude smaller than would be necessary to cause an air embolic stroke or embarrass your heart function. The real reason for the tapping practice is to accurately dose the medication we are giving.

These are regular-walled medical point needles. They are for intramuscular, subcutaneous, and other injections and are available in a wide range of gauges and lengths.The air pressure plays an important role in the filling of syringe as the liquid medicine rushes into the syringe when air pressure inside it decreases on pulling piston out.