Respiratory systems

Question 1

What is external respiration?

Answer 1

O2 and CO2 exchange between the lungs and the blood

Question 2

What is internal respiration?

Answer 2

O2 and CO2 exchange between the blood and muscle tissues

Question 3

How is O2 transported through the body?

Answer 3

• 97% within haemoglobin
• 3% within blood plasma

Question 4

How is CO2 transported through the body?

Answer 4

• 70% dissolved in water as carbonic acid
• 23% within haemoglobin
• 7% dissolved in blood plasma

Question 5

What are the values for an untrained performer at resting levels?

Answer 5

Breathing rate = 12-15
Tidal volume = 500ml
Minute ventilation = 6-7.5L/min

Question 6

What are the values for an untrained performer during maximal exercise levels?

Answer 6

Breathing rate = 40-50
Tidal volume = 2.5-3L
Minute ventilation = 100-150L/min

Question 7

Describe inspiration at rest?

Answer 7

• external intercostals contact pulling the rib cage up and out
• diaphragm contracts and flattens
• volume of the thoracic cavity increases
• pressure of the thoracic cavity decreases
• air diffuses into the lungs

Question 8

Describe expiration at rest?

Answer 8

• external intercostals relax moving the rib cage down and in
• the diaphragm relaxes and domes
• volume of the thoracic cavity decreases
• pressure of the thoracic cavity increases
• air diffuses out of the lungs

Question 9

What muscles are recruited during inspiration during excersie?

Answer 9

• sternocleidomastoid
• scalene
• pectoralis minor

Question 10

What muscles are recruited during expiration during exercise?

Answer 10

• internal intercostals
• rectus abdominus

Question 11

Where is the respiratory control centre located and what are it’s 2 subdivisions?

Answer 11

Located in the medulla oblongata

• inspiratory centre
• expiratory centre

Question 12

How does the inspiratory control centre regulate breathing rate?

Answer 12

Nerve impulses are generated and stimulate inspiratory muscles via

• intercostal nerve to external intercostals
• phrenic nerve to diaphragm

Question 13

Describe what happens during external respiration?

Answer 13

Gas exchange at the lungs between deoxygenated blood in the capillaries and oxygenated blood in the alveoli

O2 moves from a high PO2 in the alveoli (105) to a low PO2 in the capillaries (40-65) via diffusion

Question 14

What happens during external respiration during excercise?

Answer 14

• O2 diffusion gradient steepens and O2 continues to diffuse from the alveoli into the blood
• CO2 diffusion gradient steepens and CO2 diffuses from a high PCO2 in capillaries to a low PCO2 in alveoli

Question 15

What happens during internal respiration?

Answer 15

Gas exchange between oxygenated blood in the capillaries and CO2 producing muscle cells

O2 moves from a high PO2 in the capillary (100) to a low PO2 in the muscles (40) via diffusion

CO2 moves from a high PCO2 (46) in the muscle cell to a low PCO2 in the capillaries

Question 16

What happens during internal respiration during exercise?

Answer 16

• O2 diffusion gradient steepens ad O2 diffuses from capillary to muscles
• CO2 diffusion gradient steepens and CO2 diffuses from muscles to capillary

Question 17

What is the Bohr shift?

Answer 17

movement of oxyhaemoglobin dissociation curve to the right caused by increased blood acidity

Question 18

What effect does the Bohr shift have?

Answer 18

• increased blood and muscle temperature
• increased PP of CO2
• increased lactic acid and carbonic acid production lowering PH

Question 19

What impact does the Bohr shift have on the performer?

Answer 19

O2 saturation is lower and so O2 dissociation to respiring tissues is greater

enhances volume of O2 available for diffusion