O Level Biology

Explain the role of the ribs, the internal and external intercostal muscles and the diaphragm in producing volume and pressure changes in the thorax, causing the movement of air into and out of the lungs (breathing)

Identify, on diagrams and images, the ribs, internal and external intercostal muscles and the diaphragm

Describe the characteristics of, and describe the role of, the exchange surface of the alveoli in gas exchange

Identify, on diagrams and images, the larynx, trachea, lungs, bronchi, bronchioles, alveoli and associated capillaries

Investigate and explain the differences between inspired and expired air

State the percentages of the gases in atmospheric air

Describe the features of gas exchange surfaces in humans, limited to: large surface area, thin surface, good blood and air supply

State the function of the hepatic portal vein as the route taken to the liver by most of the molecules and ions absorbed from the ileum

Understand that water is absorbed from the lumen of the small intestine and the colon, but that most absorption of water happens in the small intestine

Explain the significance of villi and microvilli in increasing the internal surface area of the ileum