The syringe plunger works by creating a pressure difference that allows fluids to be drawn into or expelled from the syringe. The anatomy of a syringe plays a critical role in how the plunger functions.
Mechanism Explained
Here’s a breakdown of the plunger’s functionality:
-
Drawing Fluid (Suction):
- When the plunger is pulled back, it increases the volume inside the syringe barrel.
- This increase in volume decreases the pressure inside the syringe, creating a partial vacuum.
- The higher atmospheric pressure outside the syringe then forces fluid into the syringe through the needle to equalize the pressure.
-
Expelling Fluid (Injection):
- When the plunger is pushed in, it decreases the volume inside the syringe barrel.
- This decrease in volume increases the pressure inside the syringe.
- The higher pressure inside the syringe forces the fluid out through the needle into the injection site.
Key Components
- Plunger: The part you push or pull to create pressure changes.
- Barrel: The hollow tube that holds the fluid.
- Needle: The sharp, hollow tube used to pierce the skin.
- Rubber Stopper/Piston: The rubber tip on the plunger creates a tight seal against the barrel walls, essential for maintaining pressure.
Factors Affecting Syringe Functionality
- Volume Regulation: The syringe volume is typically regulated by ISO, the International Organization for Standardization (0:10).
- Light Sensitivity: Special syringes are sometimes used in light-sensitive applications or clinical trials (0:10).
- Tight Seal: A proper seal between the plunger's rubber stopper and the barrel is crucial for effective suction and injection.
