Question

Respiratory centre of brain is sensitive to
(A) More \[{O_2}\] concentration in blood
(B) More \[C{O_2}\] concentration in blood
(C) Accumulation of blood in brain
(D) All of the above

Answer 1

Hint: The brain is the widest and uppermost part of the central nervous system which lies protected inside the cranial cavity of the skull and controls all activities of the nervous system. The brain is covered by three meninges- pia mater, arachnoid, and dura mater.

Complete answer: During respiration, the level of carbon dioxide in the blood acts on medulla oblongata which controls the mechanism of respiration. The respiratory centers contain chemoreceptors that detect pH levels in the blood. Injury to respiratory groups can cause various breathing disorders that may require mechanical ventilation. The respiratory center is located in the medulla oblongata and pons in the brain. The medulla oblongata is a cylindrical-conical hindermost part of the brain which has an internal cavity called the fourth ventricle. The latter is continuous with the other and central canal of the spinal cord. The anterior (proximal) region has intermixed grey and white matters while the remaining medulla has white matter on the exterior and grey matter internally. Part of the roof is non-nervous, fused with a pia meter to form a highly folded posterior choroid plexus. It is followed by two lateral apertures or foramina of luschka and a median aperture or foramen of Magendie. The apertures connect external and internal cerebrospinal fluids of the brain. The medulla oblongata is believed to cause a change of nervous tracts from left to right. And vice versa. Medulla oblongata has a respiratory centre, cardiac centre, reflex centres for swallowing, vomiting, peristalsis, secretion and activity of alimentary canal, salivation, coughing, sneezing, etc. Vasomotor centre (diameter of blood vessels). Pons is a broad cross-wise band of fibres found on the inferior broadside of the medulla oblongata that connects the cerebrum, cerebellum, medulla and spinal cord for functioning as a relay centre amongst different parts and sides of the brain.

So, the correct answer is option B i,e More \[C{O_2}\] concentration in blood.

Note: Central respiratory chemoreceptors are cells that are sensitive to changes in brain \[PC{O_2}\] or pH and contribute to the stimulation of breathing elicited by hypercapnia or metabolic acidosis. \[C{O_2}\] most likely works by lowering pH.