8 Transport in mammals
As animals become larger, more complex and more active, transport systems become essential to supply
nutrients to, and remove
... [Show More] waste from, individual cells. Mammals are far more active than plants and require
much greater supplies of oxygen. This is transported by haemoglobin inside red blood cells.
8.1 The circulatory system Learning outcomes
Candidates should be able to:
1 state that the mammalian circulatory system is a closed double
circulation consisting of a heart, blood and blood vessels
including arteries, arterioles, capillaries, venules and veins
2 describe the functions of the main blood vessels of the
pulmonary and systemic circulations, limited to pulmonary
artery, pulmonary vein, aorta and vena cava
3 recognise arteries, veins and capillaries from microscope
slides, photomicrographs and electron micrographs and make
plan diagrams showing the structure of arteries and veins in
transverse section (TS) and longitudinal section (LS)
4 explain how the structure of muscular arteries, elastic arteries,
veins and capillaries are each related to their functions
5 recognise and draw red blood cells, monocytes, neutrophils and
lymphocytes from microscope slides, photomicrographs and
electron micrographs
6 state that water is the main component of blood and tissue
fluid and relate the properties of water to its role in transport
in mammals, limited to solvent action and high specific heat
capacity
7 state the functions of tissue fluid and describe the formation of
tissue fluid in a capillary network
8.2 Transport of oxygen and carbon
dioxide
Learning outcomes
Candidates should be able to:
1 describe the role of red blood cells in transporting oxygen and
carbon dioxide with reference to the roles of:
• haemoglobin
• carbonic anhydrase
• the formation of haemoglobinic acid
• the formation of carbaminohaemoglobin
2 describe the chloride shift and explain the importance of the
chloride shift
3 describe the role of plasma in the transport of carbon dioxide
4 describe and explain the oxygen dissociation curve of adult
haemoglobin
5 explain the importance of the oxygen dissociation curve at
partial pressures of oxygen in the lungs and in respiring tissues
6 describe the Bohr shift and explain the importance of the Bohr
shift
Cambridge International AS & A Level Biology 9700 syllabus for 2022, 2023 and 2024. Subject content
Back to contents page www.cambridgeinternational.org/alevel 25
8.3 The heart Learning outcomes
Candidates should be able to:
1 describe the external and internal structure of the mammalian
heart
2 explain the differences in the thickness of the walls of the:
• atria and ventricles
• left ventricle and right ventricle
3 describe the cardiac cycle, with reference to the relationship
between blood pressure changes during systole and diastole and
the opening and closing of valves
4 explain the roles of the sinoatrial node, the atrioventricular
node and the Purkyne tissue in the cardiac cycle (knowledge of
nervous and hormonal control is not expected) [Show Less]