Syringes and Lungs
A syringe is a device used for taking in or expelling fluids (typically liquids). Syringes work because, whenever possible, fluids will flow from regions of higher pressure to those of lower pressure.
To take a fluid into a syringe, the operator increases the volume of the interior of the syringe by pulling back the stopper. The increase in volume decreases the pressure inside of the syringe, and the fluid at a higher pressure on the outside of the syringe flows to the inside with a lower pressure. Fluid flow continues until the pressure inside of the syringe is equal to the pressure outside of the syringe.
When ejecting a fluid from a syringe, the opposite occurs. The operator decreases the volume of the syringe interior by depressing the stopper. The decrease in volume increases the pressure inside of the syringe, and the fluid at the higher pressure inside the syringe flows to the outside with a lower pressure. Fluid flow continues until the pressure inside of the syringe is equal to that outside of the syringe.
In simple terms, the lungs work like a syringe. When a person inhales, he increases the volume inside of his lungs. This increase in volume decreases the pressure inside the lungs, and the air at a higher pressure outside of the body flows into the lungs with a lower pressure. When a person exhales, he decreases the volume of his lungs. This decrease in volume increases the pressure inside of the lungs, and the air inside of the lungs moves from higher pressure inside of the lungs to lower pressure outside of the body.
To take a fluid into a syringe, the operator increases the volume of the interior of the syringe by pulling back the stopper. The increase in volume decreases the pressure inside of the syringe, and the fluid at a higher pressure on the outside of the syringe flows to the inside with a lower pressure. Fluid flow continues until the pressure inside of the syringe is equal to the pressure outside of the syringe.
When ejecting a fluid from a syringe, the opposite occurs. The operator decreases the volume of the syringe interior by depressing the stopper. The decrease in volume increases the pressure inside of the syringe, and the fluid at the higher pressure inside the syringe flows to the outside with a lower pressure. Fluid flow continues until the pressure inside of the syringe is equal to that outside of the syringe.
In simple terms, the lungs work like a syringe. When a person inhales, he increases the volume inside of his lungs. This increase in volume decreases the pressure inside the lungs, and the air at a higher pressure outside of the body flows into the lungs with a lower pressure. When a person exhales, he decreases the volume of his lungs. This decrease in volume increases the pressure inside of the lungs, and the air inside of the lungs moves from higher pressure inside of the lungs to lower pressure outside of the body.