11. Gas Exchange

11.1 Gas exchange in humans

Core

• List the features of gas exchange surfaces in humans, limited to large surface area, thin surface, good blood supply and good ventilation with air

• Name and identify the lungs, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries

• State the differences in composition between inspired and expired air, limited to oxygen, carbon dioxide and water vapour

• Use limewater as a test for carbon dioxide to investigate the differences in composition between inspired and expired air

• Investigate and describe the effects of physical activity on rate and depth of breathing

Supplement

• Name and identify the internal and external intercostal muscles

• State the functions of the cartilage in the trachea

• Explain the role of the ribs, the internal and external intercostal muscles and the diaphragm in producing volume and pressure changes in the thorax leading to the ventilation of the lungs

• Explain the differences in composition between inspired and expired air

• Explain the link between physical activity and rate and depth of breathing in terms of the increased carbon dioxide concentration in the blood, detected by the brain, causing an increased rate of breathing

• Explain the role of goblet cells, mucus and ciliated cells in protecting the gas exchange system from pathogens and particles