Answer :
Final answer:
The normal respiratory rate of an adult should be between 12-20 breaths per minute, and this rate decreases from infancy to adolescence. The rate is controlled by the medulla oblongata in the brain and is crucial for maintaining effective gas exchange in the lungs.
Explanation:
The normal respiratory rate of an adult should be between 12-20 breaths per minute. For children, this rate decreases from birth to adolescence. Infants under 1 year old typically have a respiratory rate between 30 and 60 breaths per minute, which gradually slows down as they grow. By around 10 years of age, the normal rate is closer to 18 to 30 breaths per minute. By the time they reach adolescence, their respiratory rate aligns with that of an adult, ranging from 12 to 18 breaths per minute.
Breathing is largely an involuntary process controlled by the respiratory center in the brain, specifically the medulla oblongata, which responds to the levels of carbon dioxide, oxygen, and pH in the blood. The respiratory rate, along with the tidal volume (the amount of air inhaled during a normal breath), is crucial for maintaining efficient gas exchange in the lungs. It helps to regulate the alveolar ventilation, which in turn prevents the buildup of carbon dioxide in the alveoli.