C4 - Control of breathing

Question 1

What are the two ways breathing is controlled?

Answer 1

• Neutral control
• Chemical control

Question 2

Neutral control is …

Answer 2

• Breathing is under involuntary control
• Controlled by respiratory centres of the brain
• Controlled by neurons found in the brain stem
• Key area of the brain controlling involuntary functions (respiration/ breathing) is the medulla oblongata

Question 3

What is expiration?

Answer 3

• A passive process, as the diaphragm simply relaxes allowing air to leave the lungs

Question 4

What is inspiration?

Answer 4

• An active process, as the diaphragm actively contracts which causes air to be drawn into the lungs

Question 5

What are neurons?

Answer 5

• Cells that conduct nerve impulses

Question 6

What is the medulla oblongata?

Answer 6

• Located in the middle of the brain, essential for involuntary functions like heart beat, breathing and sneezing

Question 7

What are the two areas essential for respiration?

Answer 7

• Dorsal respiratory group (DRG)
• Ventral respiratory group (VRG)

Question 8

What is the VRG responsible for?

Answer 8

• The rhythm generation that allows rhythmic and continuous breathing

Question 9

Chemical control is …

Answer 9

• Continually changing levels of oxygen and carbon dioxide in the blood which impacts on breathing control
• These are chemicals that respond to fluctuation in the gas levels known as chemoreceptors
• As a result of this they will send signals to the medulla that will then regulate and make changes to the breathing rate

Question 10

Where are chemoreceptors found and what do they do?

Answer 10

• Found in the medulla, the aortic arch and the carotid arteries
• Detect minute changes in blood carbon dioxide levels as well as changes in blood acidity (pH levels of lactic acid)