SL Content Statements

• B3.2.1

  Adaptations of capillaries for exchange of materials between blood and the internal or external environment
  

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  Adaptations should include a large surface area due to branching and narrow diameters, thin walls, and fenestrations in some capillaries where exchange needs to be particularly rapid.
  

• B3.2.2

  Structure of arteries and veins
  

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  AOS: Students should be able to distinguish arteries and veins in micrographs from the structure of a vessel wall and its thickness relative to the diameter of the lumen.

• B3.2.3

  Adaptations of arteries for the transport of blood away from the heart
  

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  Students should understand how the layers of muscle and elastic tissue in the walls of arteries help them to withstand and maintain high blood pressures.
  

• B3.2.4

  Measurement of pulse rates

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  AOS: Students should be able to determine heart rate by feeling the carotid or radial pulse with fingertips. Traditional methods could be compared with digital ones.

• B3.2.5

  Adaptations of veins for the return of blood to the heart

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  Include valves to prevent backflow and the flexibility of the wall to allow it to be compressed by muscle action.

• B3.2.6

  Causes and consequences of occlusion of the coronary arteries

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  AOS: Students should be able to evaluate epidemiological data relating to the incidence of coronary heart disease.
  NOS: Students should understand that correlation coefficients quantify correlations between variables and allow the strength of the relationship to be assessed. Low correlation coefficients or lack of any correlation could provide evidence against a hypothesis, but even strong correlations such as that between saturated fat intake and coronary heart disease do not prove a causal link.