Breathing and gaseous exchange

Question 1

Process of inhalation

Answer 1

1 - diaphragm contracts and flattens
2 - intercostal muscles contract pulling the rib cage upwards and outwards
3 - The volume of the chest cavity increases and the elastic lungs expand
4 - oxygen rich air outside rushes down the trachea and bronchi to fill the expanded lungs

Question 2

process of exhalation

Answer 2

1 - The diaphragm relaxes and becomes dome shaped
2 - The intercostal muscles relax and the rib cage moves inwards and downwards
3 - The volume of the chest cavity decreases and the elastic lungs are squashed
4 - The carbon dioxide Rich air in the lungs is pushed through the air passages to the exterior

Question 3

how gaseous exchange takes place

Answer 3

When fresh air is drawn into the lungs, an exchange of gases
takes place in the alveoli.
• Oxygen diffuses from the alveoli, where it is in a high
concentration in the inhaled air, into the blood which transports the
gas to the cells of the body for cellular respiration.
• Carbon dioxide (a waste product from cell respiration) diffuses
from the blood into the alveoli (where it is in a lower concentration
in the inhaled air than in the blood) to be exhaled.

Question 4

Transport of gases

Answer 4

5% of carbon dioxide is carried in solution in the blood plasma
10% of the carbon dioxide combines with haemoglobin to form carbaminohaemoglobin
majority of carbon dioxide about 85% is transported as bicarbonate irons in the blood plasma

Question 5

oxygen plush haemoglobin

Answer 5

oxyhaemoglobin