IB Biology: C3.1-Feedback Control of Ventilation Rate

Front

Where is the ventilation rate of the lungs controlled?

Back

The ventilation rate of the lungs is controlled by a group of cells located in the medulla oblongata of the brain called the respiratory centres.

Front

What do the respiratory centres in the medulla receive?

Back

The respiratory centres in the medulla receive sensory impulses from chemoreceptors in the aorta and carotid arteries that monitor blood pH, CO2 and O2 levels.

Front

How is an increase in CO2 concentration in the blood detected?

Back

An increase in the CO2 concentration in the blood is detected by chemoreceptors, which then send impulses to the respiratory centre.

Front

What happens when the respiratory centre receives impulses about increased CO2?

Back

The respiratory centre sends impulses to the diaphragm and intercostal muscles to increase the rate of ventilation.

Front

How does increasing CO2 concentration affect blood pH?

Back

Increasing CO2 concentration lowers blood pH as CO2 dissolves in the blood plasma to form carbonic acid.

Front

What role do chemoreceptors play in response to lowered blood pH?

Back

Chemoreceptors in the aorta and carotid arteries detect the lowering of blood pH and send impulses to the respiratory structures to increase the ventilation rate.