Question

Human beings have a significant ability to maintain and moderate the respiratory rhythm to suit the demands of the body. If :
Respiratory rhythm centre in medulla - R
Pneumotaxic centre in pons - PT
Chemosensitive area in medulla - C1
Peripheral chemoreceptors in aortic arch and carotid artery - C2

Find out the correct path for regulation of respiration.

• A. $C_2\to R\to PT\to C_1$
• B. $PT\to \underset{\underset{C_1}{\uparrow }}{R}\leftarrow C_2$
• C. $C_1\to \underset{\underset{R}{\uparrow }}{PT}\to C_2$
• D. $PT\to \underset{\underset{R}{\uparrow }}{C_2}\to C_1$

Answer 1

The correct option is B $PT\to \underset{\underset{C_1}{\uparrow }}{R}\leftarrow C_2$

Human beings have various mechanisms in order to regulate and maintain the respiratory rhythm in such a way that the demands of the various tissues present in the body are met. The medulla region of the brain contains the respiratory rhythm centre, which is a specialised centre that plays an important role in the above mentioned mechanism. The pneumotaxic centre which is present in the pons in the hindbrain, has the ability to alter the respiratory rate by altering the duration of inspiration. Hence, it is capable of moderating the functions of the respiratory rhythm centre. The medulla region of the brain also consists of a chemosensitive area. It is located near the rhythm centre. This area is highly sensitive to carbon dioxide and hydrogen ions. Hence, it can sense the increase of these substances. When there is a rise in these substances , the chemosensitive area gets activated and sends signals to the rhythm centre to regulate the respiratory process in order to counteract and bring the increase or decrease back to normal. The peripheral chemoreceptors that are present in the aortic arch and carotid artery also perform a similar function as the chemosensitive area which is present in the medulla. These receptors are also able to sense an increase in the concentrations of carbon dioxide and $H^{+}$ ions. Hence, they also are capable of sending signals to the rhythm centre to eliminate these substances from the body. Hence, the rhythm centre acts as a very specialised centre which receives signals from various other centres and controls the regulation of the respiratory process.