What is a...

Cough

  There is excess mucus or other irritant matter from external sources – dirt, smoke, household cleaners – lying on the surface of the respiratory tract, and your body is trying to expel them by propelling it violently upwards. A cough is the sudden forced exhalation to clear the trachea and larynx of mucus that contains bacteria and dust.

Sneeze

Sneezing is a procedure of expelling the harmful bacteria and virus which has entered the body and multiply themselves during cold, allergic reactions or when dust blows on our face.

Yawn

A long inhalation of air due to a variety of causes which may have inncreased carbon dioxide concentration in the blood

Scientists speculate that the onset of a yawn is triggered either by fatigue, or by sheer boredom as, at those times, breathing is shallow, and little oxygen is carried to the lungs by the oxygen-toting cardiovascular system.

When one yawns, his or her alertness is heightened, as the sudden intake of oxygen increases the heart rate, rids the lungs and the bloodstream of the carbon dioxide buildup, and forces oxygen through blood vessels in the brain, while restoring normal breathing and ventilating the lungs.

Hiccup

A hiccup is a kind of forced intake of breath, caused by muscle spasms in your chest and throat.The "hic" noise comes when the breath is cut off by the snapping shut of your glottis