Respiratory system and control centre

Question 1

Structure of the respiratory system:

• N P
• O C
• P
• L
• T
• L
• B

Answer 1

Nasal passage 
Oral cavity 
Pharynx 
Larynx
Trachea 
Lung 
Bronchi

Question 2

Name the seven components of bronchi

Answer 2

Pulmonary vein, alveolar duct, connective tissue, capillary beds, alveoli and pulmonary artery

Question 3

Why are alveoli efficient at gaseous exchange?

Answer 3

• Walls are only one cell thick
• Lined with fluid
• Surrounded by an extensive capillary bed
  (Large surface area)

Question 4

Define breathing rate

Answer 4

Number of inspirations or expirations in one minute (f) average 12-15

Question 5

Define tidal volume

Answer 5

Volume of air inspired or expired in one breath (TV) average 500ml

Question 6

Define minute ventilation

Answer 6

The volume of air expired per minute (VE)

Question 7

What is tidal volume dependent on?

Answer 7

Size of lungs, age, gender, fitness and respiratory conditions, approx. 350ml goes to the alveoli

Question 8

What’s the average breathing rate for a trained and untrained athlete?

Answer 8

Un - 12-15

Tr - 11-12

Question 9

What’s the average tidal volume for a trained and untrained athlete?

Answer 9

500ml for both

Question 10

What’s the average minute ventilation for a trained and untrained athlete?

Answer 10

Un - 6-7.5l/min

Tr - 5.5-6l/min

Question 11

What is a spirometer?

Answer 11

A medical test using a small machine attached by a cable to a mouthpiece to diagnose and monitor lung conditions by measuring how much air you can expire in a forced breath out

Question 12

What is external respiration?

Answer 12

Oxygen diffuses into the blood and carbon dioxide diffuses into alveoli, within the lungs

Question 13

What is internal respiration?

Answer 13

Occurs in the muscles where where oxygen diffuses out of the blood and CO2 diffuses out of cells

Question 14

How is oxygen transported?

Answer 14

• Haemoglobin in red blood cells as oxyhaemoglobin (97%)

- Blood plasma (3%)

Question 15

How is CO2 transported?

Answer 15

• Dissolved in water as carbonic acid (70%
• Carried in haemoglobin as carbaminohaemoglobin (23%)
• In the blood plasma (7%)

Question 16

For a trained athlete, what is their average f, TV and VE at maximal activity?

Answer 16

f - 50-60
TV - 3-3.5l
VE - 160-210l/min

Question 17

For an untrained athlete, what is their average f, TV and VE at maximal activity?

Answer 17

f - 40-50
TV - 2.5-3l
VE - 100-150l/min

Question 18

What is the function of the RCC and where is it located?

Answer 18

• Regulate breathing

- Medulla Oblongata

Question 19

What does the Inspiratory Centre do at rest?

Answer 19

• Sends impulse to respiratory muscles
• When stimulated, muscles contract which increases the volume of the thoracic cavity causing inspiration
• When stimulation stops, muscles relax which decreases the volume of the thoracic cavity causing expiration

Question 20

What does the Inspiratory Centre do during exercise?

Answer 20

• Increases stimulation of diaphragm and external intercostals
• Stimulates additional inspiratory muscles

Question 21

What does the Expiratory Centre do at rest and during exercise?

Answer 21

Rest - inactive

Exercise - Stimulates expiratory muscles to force expiration

Question 22

What supplies information to the inspiratory system?

Answer 22

• Proprioreceptors (motor activity)
• Chemoreceptors (acidity CO2 and O2 concentration)
• Thermoreceptors (blood temperature)

Question 23

What nerves and muscles do the inspiratory centre control?

Answer 23

Phrenic nerve to diaphragm

Intercostal nerve to external intercostal nerves

Question 24

What supplies information to the expiratory centre?

Answer 24

Baroreceptors (blood pressure)

Question 25

What does the expiratory centre send stimulus to?

Answer 25

Internal intercostals and abdominals