Construction
A syringe is a large tube with a plunger inserted in one end and the other end resulting in a smaller tube (the needle). Older syringes used to be made mainly of glass and metal, but modern syringes are constructed of lighter plastic and only have metal in the needle portion.
Filling
Filling an empty syringe is accomplished by inserting the needle into a bottle or reservoir of liquids and pulling the plunger back, causing suction. This draws the liquid into the syringe and readies it for injection into the body.
Injection
The needle's point is sharp enough to penetrate the skin easily and acts as a conduit for the liquid inside the syringe to be inserted (or "injected") into the body. The liquid is forced from the syringe by pushing the plunger toward the needle end of the syringe.
Uses
Syringes are most widely used in the medical community (physicians, hospitals and clinics) to introduce medicine into the body quickly and efficiently. There are two types in injection: subcutaneous and intravenous. Subcutaneous injections aim to deposit medicine immediately under the skin, either in a muscle or a layer of fat. Intravenous injections target a blood vessel (such as a vein) in order to introduce medicines into the bloodstream.
Measurement
Hospitals have a long-standing measurement of liquids dispensed in syringes based upon the metric system. Liquids are measured as "milliliters" or 1000th of a liter but, oddly, are called "CCs" by medical staff which refers to "cubic centimeters" which is close to a milliliter (.9746 of a milliliter).
Other Types of Syringes
Some syringes do not have needle portions at all. Irrigation syringes are used by dentists, for example, to irrigate the gums after oral surgery. These syringes end in a fixed plastic tip and are used to squirt water or a saline solution into a sensitive area in order to remove debris and detritus.
