Question

1)Why do we yawn when we feel sleepy?

2) How does sneezing help us ?

3) Is inhaling pure oxygen safe ? explain.

Answer 1

Hey, mate here is your answer✌✌》》

Ans.1) When you feel sleepy..it is actually the brain cells which are in a sense of saying..going to fall asleep for lack of oxygen (hypoxia or hypoxemia). Also when we feel drowsy, our respiratory rate being controlled by reflex centres in our brain falls. This is a vicious cycle. The yawn breaks this cycle.
Now if you go into details, the sum of the partial pressures of oxygen and carbon di oxide in blood tries to remain constant. So if there is less oxygen, it can imply more carbon di oxide and vice versa.
When you yawn, it is simply a big volume cycle of inspiration (of oxygen) and expiration (of carbon di oxide). This makes up for the defecient oxygen reaching the brain and washes out excess carbon di oxide. Brain gets more oxygen, the vicious cycle is broken and brain cells are happier.

Ans.2) "Sneezing is an important part of the immune process, helping to keep us healthy and sniffle-free" Kao says. Sneezes protect your body by clearing the nose of bacteria and viruses, Kao explains. ... As result, air -- along with saliva and mucus -- is forced out of your mouth and nose. Voila, you've sneezed.

Ans.3) Our blood has evolved to capture the oxygen we breathe in and bind it safely to the transport molecule called haemoglobin. If you breathe air with a much higher than normal O2 concentration, the oxygen in the lungs overwhelms the blood's ability to carry it away.

☆☆Hope these answers will help you..《《☆☆

Answer 2

this is given by nature , no reason is behind that.

when we sneeze , all the dust particles or waste of nose through .

Oxygen present in our surrounding is not idle the air consists greater concentration of poisonous gases and less concentration of oxygen