Breathing and gaseous exchange Flashcards
Process of inhalation
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
process of exhalation
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
how gaseous exchange takes place
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.
Transport of gases
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
oxygen plush haemoglobin
oxyhaemoglobin