EXTRA: Curiosities

Some curiosities about the respiratory system are: 

• The hiccup is caused by a suddenly contraction of the diaphragm. Then, the air enters very fast and the vocal cords get close, and this cause the hiccup sound.

• The American farmer Charles Osborne have a hiccup attack that start in 1922 and finish in 1990 (68 years of hiccup). 

• When we cough, the air can exit with a speed of 140 km/h.