Question

Control of Breathing. Select the MOST CORRECT answer.

An increase in the partial pressure of carbon dioxide in plasma leads to a stimulation of medullary chemoreceptors.

A decrease in the partial pressure of oxygen in plasma leads to a stimulation of peripheral chemoreceptors.

An increase in ventilation leads to a decrease of the partial pressure of carbon dioxide in plasma which leads to an increase of CSF pH which leads to a decrease of respiratory drive.

Both a) and b) are correct and c) is incorrect.

a), b) and c) are all correct.

Regarding the regulation of plasma glucose levels in humans (select the MOST CORRECT statement):

		Although glucagon and insulin have opposing effects on blood glucose levels, both of these peptide hormones bind to a distinct subtype of G protein-coupled receptor on the surface of target cells.
		High plasma glucose levels lead to an increase in gluconeogenesis by the liver.
		Low levels of plasma glucose lead to an increase in glycogenolysis by the liver.
		Both a) and b) are correct and c) is incorrect
		a), b) and c) are all correct

Answer 1

Answer: Control of breathing

The right choice is: (a), (b) and (c) are all correct.

Explanation: Central chemoreceptors present on the Medullary surface detects increase in pCO2 and increases the ventilation due to which more CO2 is exhaled out and the pCO2 level comes to normal. Peripheral chemoreceptors present in aortic arch and carotid artery bodies detect low pO2 and then increases respiratory rate and tidal volume so that more oxygen enters the lungs and diffuses inside the blood and blood pO2 becomes normal. During Hyperventilation, exhalation is more than inhalation due to which more CO2 is exhaled out which results in decreased pCO2 in blood, this stimulates chemoreceptors which decreases the respiratory rate so that less CO2 is exhaled and pCO2 becomes normal.