The Heart Has Four Valves and All Are One-Way
A valve controls the flow of a fluid in one direction. The word once meant the leaf of a folding door.
A valve is a device that controls the flow of a liquid or gas, usually allowing it in only one direction. Latin *valva* meant the leaf of a folding door, which is exactly what a simple valve is — a flap that swings open one way and seals when pushed the other. The heart has four of them, and the sound of a heartbeat is those flaps snapping shut. In British English a *valve* was also the vacuum tube in early radios, called a *tube* in America.
- A flow control device. *A safety valve.*
- A heart valve. *The mitral valve.*
- A vacuum tube (UK). *A radio valve.*
- A shell half. *A bivalve.*
- Latin — *valva*, a door leaf. *The source.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | valve | A valve. |
| Plural | valves | Valves. |
| Compound | bivalve | A bivalve. |
| American | tube | A vacuum tube. |
| Latin | valva | A door leaf. |
- The valve controls the flow.Engineering.
- A heart valve had to be replaced.Medicine.
- Valva meant a folding door.Etymology.
The four heart valves
- Tricuspid — between the right atrium and ventricle
- Pulmonary — from the right ventricle to the lungs
- Mitral — between the left atrium and ventricle
- Aortic — from the left ventricle to the body
- The heartbeat sound is these valves snapping shut, not the muscle contracting
Latin *valva*, the leaf of a folding door, from a root meaning to turn.
What makes the sound of a heartbeat?
The valves snapping shut. The two sounds come from the two pairs of valves closing in sequence.
Why do the British call a vacuum tube a valve?
Because it allows current to flow in one direction only, exactly as a mechanical valve does with a fluid.