Syringe
From Wikipedia, the free encyclopedia
A syringe nowadays nearly always means a medical syringe, but it can mean any of these:
- A simple hand-powered piston pump consisting of a plunger that can be pulled and pushed along inside a cylindrical tube (the barrel), which has a small hole on one end, so it can suck liquid in and then squirt it out by the same hole. The word "syringe" came from the Greek συριγξ = "tube" (see also Syrinx).
- In former times the word "syringe" also meant big two-handed pumps of this type used e.g. as early firefighting water pumps.
- Nowadays the word "syringe" is restricted to smaller devices, used to transfer small amounts of liquids or gases to or from otherwise inaccessible areas, including particularly hypodermic syringes used with a needle for injection.
- As a result, jet injectors are sometimes called syringes.
- Distinguish from syrinx. Also, some people use "syringes" as the plural of "syrinx".
One medical survival of the word "syringe" for uses other than injection, is in "syringing an ear out", i.e. washing unwanted matter out of the external ear canal.
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[edit] Medical syringes
Hypodermic syringes are used with hypodermic needles to inject liquid or gases into body tissues, or to remove from the body. Injecting of air into a blood vessel is undesirable, as it may cause an air embolism; preventing embolisms by removing air from the syringe is the reason for the familiar image of holding a hypodermic syringe upside down, tapping it, and expelling a small amount of liquid before an injection into the bloodstream.
The barrel of a syringe is made of plastic or glass, and usually has graduated marks indicating the volume of fluid in the syringe. Glass syringes may be sterilized in an autoclave, however, modern medical syringes are made from plastic because it is cost-effective to dispose of them, which further reduces the risk of spreading blood-borne diseases. The re-use of needles and syringes has been associated with the spread of diseases, especially HIV and Hepatitis among IV drug users.
Disposable medical syringes are sometimes used without a needle for orally administering liquid medicines to young children or animals because the dose can be measured accurately, and it is easier to squirt the medicine into the subject's mouth instead of coaxing the subject to drink out of a measuring spoon.
[edit] Standard U-100 insulin syringes
Syringes for insulin users are designed for standard U-100 insulin. The dilution of insulin is such that 1ml of insulin fluid has 100 standard "units" of insulin. Since insulin vials are typically 10ml, each vial has 1000 units.
Insulin syringes are made specifically for self injections and have friendly features:
- shorter needles, as insulin injections are subcutaneous (under the skin) rather than intermuscular,
- finer gauge needles, for less pain, and
- markings in insulin units to simplify drawing a measured dose of insulin.
[edit] Multishot needle syringes
There are needle syringes designed to reload from a built-in tank (container) after each injection, so they can make several or many injections on a filling. These are not used much in human medicine because of the risk of cross-infection via the needle. An exception is the personal insulin autoinjector used by diabetic patients.
[edit] Controls
In certain jurisdictions, the sale or possession of hypodermic syringes may be controlled or prohibited without a prescription, due to its potential use with illegal intravenous drugs.
[edit] Non-medical laboratory uses
Medical-grade disposable hypodermic syringes are often used in chemistry laboratories for its convenience and low cost. They are often used for measuring and transferring solvents and reagents where a high precision is not required.
The polyethylene construction of these disposable syringes usually makes them rather chemically resistant. There is, however, a risk of the contents of the syringes leaching plasticizers from the syringe material. Non-disposable glass syringes may be preferred where this is a problem. Glass syringes may also be preferred where a very high degree of precision is important (i.e. quantitative chemical analysis), because their engineering tolerances are lower and the plungers move more smoothly. In these applications, the transfer of pathogens is usually not an issue.
Used with a long needle or cannula, syringes are also useful for transferring fluids through rubber septa when atmospheric oxygen or moisture are being excluded. Examples include the transfer of air-sensitive or pyrophoric reagents such as phenylmagnesium bromide and n-butyllithium respectively. Glass syringes are also used to inject small samples for gas chromatography (1 μl) and mass spectrometry (10 μl). Syringe drivers may be used with the syringe as well.
[edit] Cooking
Some culinary uses of syringes are injecting liquids (such as gravy) into other foods, or for the manufacture of candies, such as Fruit Gushers.
Syringes may also be used when cooking meat to enhance flavor and texture by injecting juices inside the meat, and in baking to inject filling inside a pastry.
[edit] Others
Syringes are used to refill ink cartridges with ink.
Sometimes a large hypodermic syringe is used without a needle for very small baby mammals to suckle from in artificial rearing.
To administer enemas or douches, there are 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. In earlier times, clyster syringes were used for that purpose.
[edit] Historical Timeline
- 9th century: The Iraqi/Egyptian surgeon Ammar ibn 'Ali al-Mawsili' technically invented the first such syringe in the 9th century using a hollow glass tube and suction to remove cataracts from patients' eyes, a practice that remained in use up until at least 1230 and which came into renewed use in the 20th century.
- About 1650: Blaise Pascal invented the syringe (not necessarily hypodermic) as an application of what is now called Pascal's law.
- 1760: Forms of intravenous injection and infusion began.
- 1853: Charles Gabriel Pravaz and Alexander Wood first developed a medical hypodermic syringe with a needle fine enough to pierce the skin.
- 1956: New Zealand pharmacist and inventor Colin Murdoch granted New Zealand and Australian patents for a disposable plastic syringe.
- 1974: First US patent for a plastic disposable syringe received by African American inventor, Phil Brooks, U.S. patent #3,802,434 received on April 9, 1974.
[edit] See also
- A jet injector injects without a needle, by squirting the injection fluid so fast that it makes a hole in the skin.
- A syrette is like a syringe except that it has a closed flexible tube (like that used for toothpaste) instead of a rigid tube and piston.
