Question

Respiratory centre of brain is stimulated by
A. Carbon dioxide content in venous blood
B. Carbon dioxide content in arterial blood
C. Oxygen content in venous blood
D. Oxygen content in arterial blood

Answer 1

Hint: The Respiratory centre of the brain is present in the medulla oblongata and pons. The respiratory centre is made up of three neurons in which two of them present in the medulla oblongata and one in the pons.

Complete answer:
Respiratory centre of the brain is stimulated by carbon dioxide content in arterial blood. When there is an increase in the carbon dioxide level in arterial blood, the respiratory centre receives signals from chemoreceptors, cerebral cortex and hypothalamus in order to maintain the carbon dioxide level in the arterial blood. The respiratory centre regulates the rate and depth of breathing and maintains the altered levels of oxygen, carbon dioxide and blood pH. This alteration in oxygen, carbon dioxide and pH caused by the hormonal changes related to stress and anxiety of hypothalamus. Respiratory centre also adjusts the homeostasis in response to physiological changes. The respiratory centre is also known as respiratory rhythm centre.
Medulla oblongata is the posterior most part that connects the various parts of the brain and spinal cord. It is small in size. The medulla contains centers responsible for controlling the processes such as respiration, cardiovascular reflexes and gastric secretions.

So, the correct answer is option B.

Note: Injury to the respiratory centre can cause severe breathing ailments. Respiratory centre is stimulated by drug amphetamine to produce faster and deeper breaths. The destruction of medulla oblongata brings about the immediate death of an organism.