A syringe consists of a plunger fitted to a tube with a small opening on one end used either to inject or suck out a liquid. There are different types of medical or surgical syringes, avaialble in different sizes , depending on the dose of medicine to be injected into the body of the patient.

Materials
The barrel of a syringe is either made of glass or plastic. It usually has graduated markings which indicate the volume of fluid/liquid medicine in the syringe, and is always transparent. Glass syringes were used traditionally and they can be sterilized in an autoclave. However, in most modern clinics and hospitals, syringes are plastic made with a rubber piston. Such modern syringes are very popular because these type of syringes seal much better between the piston and the barrel. Moreover they are cheap enough to be disposed or thrown away after being used only once, thereby reducing the risk of spreading blood-borne diseases. Most syringes are nowadays disposable. Disposable syringes are made using medical grade polypropylene. Using this syringe ensures the avoidance of blood spread infections like AIDS and Hepatitis C. Syringes that are commonly re-used are those that are used by diabetics and this is considered to be safe, if the syringe can only used by one person.

Types of syringes
Needle Syringes: They are used with hypodermic needles to inject liquid medications into body tissues; the process of giving medication into the body with a syringe and needle is called an injection. Syringes can also be used to suck out some liquid from a cavity.

Rectal and vaginal syringes: They are used for the administration of enemas or douches, there exist bulb syringes where a bulb is fitted with a nozzle, liquid is pumped into it, the nozzle is inserted into the rectum or vagina and the bulb is pressed upon for injection. There are fountain syringes where the liquid is in a bag or can and goes to the nozzle via a pipe.

Besides the above, there are certain specialized syringes like pen injections, jet injectors, pumps which are used as injections for special purpose or special treatments.

Hypodermic Needles
Insulin Syringes
Tuberculin Syringes