Question

why we yawn when we are sleepy or Drowsy. illustrate the point

Answer 1

When we are sleepy or feel drowsy, we yawn because our brain cells lack sufficient amount of oxygen. The deep breath associated with yawning helps us to drawn in more oxygen and supply the much needed oxygen to the tired body organs including the brain

Answer 2

When you feel sleepy..it is actually the brain cells which r 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. That is why we yawn when we r sleepy or drwzy

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