Human: How does a syringe needle work? Assistant: 
A syringe needle is a hollow tube that is used to inject fluids into the body. It is typically made of plastic or glass and has a sharpened tip for piercing the skin. The syringe needle is inserted into the body through an incision in the skin, and then it is moved around inside the body to deliver the fluid. The needle is then removed from the body after the injection is complete.