What are the Parts and Function of a Syringe?
A syringe is a simple yet vital medical instrument used for injecting or withdrawing fluids. It consists of several key parts working together to deliver a precise amount of liquid.
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Barrel: This is the cylindrical, hollow body of the syringe. It's usually transparent (made of glass or plastic) to allow for easy viewing of the fluid volume. The barrel holds the medication before injection. [Reference (1), (2), (4), (8), (9)]
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Plunger: A tightly fitting, cylindrical component within the barrel. The plunger is pushed to expel fluid or pulled to draw fluid into the barrel. It works in conjunction with the plunger seal/gasket to create an airtight seal. [Reference (1), (2), (4), (8), (9)]
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Plunger Seal/Gasket: This forms a seal between the plunger and the barrel, preventing leakage and ensuring accurate fluid delivery. [Reference (4)]
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Needle: A sharp, hollow tube usually made of stainless steel. It is attached to the syringe's tip and pierces the skin to allow fluid injection or withdrawal. [Reference (1), (2), (3), (9)]
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Needle Hub: The connector between the needle and the syringe. [Reference (3)]
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Needle Bevel: The slanted tip of the needle, which facilitates easier insertion into tissue. [Reference (3)]
Variations and Additional Components:
Some syringes may have additional components, depending on their design and intended use. These can include:
- Luer Lock: A threaded connection between the syringe and needle, providing a secure attachment.
- Needle Adaptor: Connects the syringe to different needles or other attachments. [Reference (3)]
- Cuff/Pilot Balloon (for specific applications): Used with endotracheal tubes for inflation. [Reference (5)]
- Stylet (for specific applications): A stiff wire that helps maintain the shape of a catheter or tube. [Reference (5)]
Practical Insights:
The design of a syringe ensures accurate fluid delivery. The airtight seal formed by the plunger and barrel allows for precise measurement and control over the injection or withdrawal process. The needle's bevel helps to minimize pain and trauma during insertion.
