Respiratory System

Question 1

what is relaxed inhalation?

Answer 1

the thoracic cavity volume is increased following contraction of the diaphragm and external intercostal muscles;
a larger volume means air pressure decreases therefore it become lower than that in the atmosphere meaning air rushes into the lungs

Question 2

how does laboured inhalation differ from relaxed?

Answer 2

during laboured inhalation, as well as the diaphragm and intercostals, other accessory muscles must also contract;
include muscles of the neck; controlled by the respiratory centre in the medulla oblongata

Question 3

list four stimuli which increase the rate and depth of breathing:

Answer 3

increased carbon dioxide concentration; increased temperature; decrease in blood pressure; increased stimulation of proprioceptors

Question 4

where are the central chemoreceptors located?

Answer 4

the medulla oblongata

Question 5

where are the peripheral chemoreceptors located?

Answer 5

the carotid bodies

Question 6

what do the chemoreceptors detect?

Answer 6

increased CO2 levels in the blood

Question 7

what do the chemoreceptors stimulate?

Answer 7

the respiratory control centre in the medulla oblongata

Question 8

how does the respiratory control centre respond to increased CO2 in the blood?

Answer 8

increased activated on the inspiratory areas; increased nerve activity / impulses to the diaphragm and intercostals (breathing muscles); increased rate and depth of breathing; increased CO2 output; decreased CO2 in blood