Question

Breathing is controlled by
(A) Lungs
(B) Trachea
(C) Medulla oblongata
(D) Hypothalamus

Answer 1

Hint: The process of exchange of oxygen from the atmosphere and carbon dioxide by the cells is called Breathing. The functions of different organs or organ systems in our body are controlled and co-ordinated by the nervous/neural system and endocrine system together. Likewise, even the process of breathing is controlled by a specific part of the brain.

Complete answer:
Oxygen is required for all the living organisms, in order to derive energy from simpler food molecules. Carbon dioxide is by product produced during the formation of energy molecules (ATP). Thus, oxygen is needed for each and every cell of our body and thereby carbon dioxide has to be eliminated from our body. This process of exchange of oxygen and carbon dioxide by the cell is called breathing.
Mechanism of breathing in each organism varies according to their habitat and levels of organisation. Lungs are the respiratory organ for terrestrial organisms, especially highly vascularised bags are found in human beings. Human respiratory system consists of a pair of external nostrils, nasopharynx, trachea, primary bronchi, secondary bronchi, tertiary bronchi which gives rise to bronchioles and terminal bronchioles. Each terminal bronchiole gives rise to a number of thin, vascularised bag-like structures called alveoli. Alveoli is the site of exchange of gases.
Breathing involves two stages, namely inspiration and expiration. Inspiration and expiration are aided by muscles present between rib cages (external & internal intercostal muscles) and diaphragm which undergo rhythmic contraction and relaxation.

The rhythmic contraction and relaxation is brought about by the neural system. Medulla oblongata region of the brain contains a specialized respiratory centre which controls the rate of inspiration and expiration. Respiratory rhythm centre present in the medulla region is primarily responsible for regulation of breathing. Pneumotaxic centres present in the pons region moderates the function of the respiratory rhythm centre.

Hence the correct answer is OPTION(C)

Note: Each part of the brain is involved in control of some or the other activities. It is important to remember the specific part of the brain associated with the particular function. Breathing is controlled by centres present in medulla oblongata. Likewise, the other organs are controlled by different parts of the brain which needs to be understood and remembered well.