The structure of the respiratory system

Question 1

What are the two main functions of the respiratory system?

Answer 1

1. Pulmonary ventilation: the inspiration and expiration of air
2. Gaseous exchange:
   -external respiration: the movement of oxygen into the bloodstream and carbon dioxide into the lungs
   -internal respiration: the release of oxygen to respiring cells for energy production and collection of waste products

Question 2

What is the pathway of air?

Answer 2

1. Air is drawn into the nasal cavity through the nose and travels down into the pharynx, larynx and trachea
2. Trachea divides into the left and right bronchi
3. Bronchi divide into smaller bronchioles and end in alveolar ducts where air moves into the alveoli

Question 3

Label this gaseous exchange system

Answer 3

Question 4

Define gaseous exchange

Answer 4

The movement of oxygen from the alveoli into the bloodstream and carbon dioxide from the blood stream into the alveoli

Question 5

What percentage of blood is plasma?

Answer 5

About 55%

Question 6

In what ways can oxygen be transported?

Answer 6

1. Carried with haemoglobin in the red blood cells (97%)
   Hb + O2 = HbO2
2. Carried within blood plasma (3%)

Question 7

In what ways can carbon dioxide be transported?

Answer 7

1. Dissolved in water and carried as carbonic acid (70%)
2. Carried with haemoglobin (23%)
   Hb + CO2 = HbCO2
3. Dissolved in blood plasma (7%)