Respiratory System During Exercise

Question 1

Explain the process of inspiration during exercise (6 marks)

Answer 1

1) Diaphragm contracts and the external intercostals contract more than at rest
2) Sternocleidomastoid and pectoralis minor contract
3) Rib cage moves up and out more than at rest
4) So more volume of air in lungs than at rest
5) So less pressure in lungs than at rest
6) So more air enters the lungs than at rest

Question 2

Explain the process of expiration during exercise ( 6 marks)

Answer 2

1) Diaphragm relaxed and the external intercostals relax more than at rest
2) Internal intercostals and rectus abdominus contracts
3) The rib cage moved down and in more than at rest
4) So less volume of air in the lungs than at rest
5) So more pressure in the lungs than at rest
6) More air leaves the lungs than at rest

Question 3

What is the respiratory control centre

Answer 3

• Situated in the brain and controls breathing rate and depth

Question 4

What is the inspiratory centre

Answer 4

Part of the respiratory control centre that controls inspiration

Question 5

What is Expiratory centre

Answer 5

Part of the respiratory control centre that controls expiration

Question 6

What is the phrenic nerve

Answer 6

The nerve that stimulates the diaphragm to contract

Question 7

What is the intercostal nerve

Answer 7

The nerve that stimulates the external intercostals to contract

Question 8

Explain the neural control mechanism of Breathing regulation during exercise (3 marks)

Answer 8

-The inspiratory centre increases stimulation of the phrenic and intercostal nerves causing the diaphragm and external intercostal muscles to contract with more force
- It also stimulates the sternocleidomastoid and pectoralis minor
- Increases volume and decreases pressure in lungs more than at rest
- More air goes in the lungs

Question 9

Explain the chemical control mechanism of breathing regulation during exercise (5 marks)

Answer 9

• Specialised Baroreceptors in lungs monitor lung stretch
• Once stretch threshold is reached the baroreceptors send info to the expiratory centre
• The expiratory centre receives info from the baroreceptors and stimulate the internal intercostals and rectus abdominis to contract
• This decreases the volume in the lungs and increases the pressure more than at rest
• More air moves out of the lungs

Question 10

Explain the effects of exercise on gaseous exchange

Answer 10

02)-PP of 02 decrease in muscles
-leading to a steeper concentration gradient between blood and muscles
- More 02 disassociates from haemoglobin and diffuses into muscle

Question 11

What is the breathing frequency figure for a untrained and trained athlete working at maximal intensity

Answer 11

Untrained: 50 breaths per minute
Trained: 60 breaths per minute

Question 12

What is the Tidal Volume figure for a untrained and trained athlete working at maximal intensity

Answer 12

Untrained athlete: 2500ml
Trained athlete: 3000ml

Question 13

What is the minute ventilation figure for a untrained and trained athlete working at maximal intensity

Answer 13

Untrained: 125l/min
Trained: 180l/min