Final answer:
The gauge number of an IV needle inversely corresponds to its thickness, with higher gauges meaning thinner needles. The statement about vessel length and resistance is false; longer vessels equate to higher resistance and lower flow.
Step-by-step explanation:
The gauge number of an intravenous (IV) needle corresponds to the thickness of the needle. Contrary to what one might think, the higher the gauge number, the thinner the needle. This follows a similar principle as described for electrical wires, where a higher gauge number indicates a thinner wire. It is important to select the appropriate gauge size for IV needles based on the type of fluid being administered and the patient's vein size.
Regarding the statement 'The longer the vessel, the lower the resistance and the greater the flow,' this is false. In blood vessels and other fluid systems in general, the longer the vessel, the higher the resistance and the lower the flow. Resistance in a vessel is affected by factors such as length, diameter, and the viscosity of the fluid. For blood vessels, a longer vessel increases the distance over which friction occurs between the blood and vessel wall, thereby increasing resistance and reducing flow.