The blood system

Topics 6.2

Essential idea: Continued availability of carbon in ecosystems depends on carbon cycling.

Understandings

6.2.U1 Arteries convey blood at high pressure from the ventricles to the tissues of the body

Pressure graph for blood vessels

6.2.U2 Arteries have muscle cells and elastic fibers in their walls

Artery wall diagram

6.2.U3 The muscle and elastic fibers assist in maintaining blood pressure between pump cycles

Muscle and elastic fibres in artery wall

6.2.U4 Blood flows through tissues in capillaries. Capillaries have permeable walls that allow exchange of materials                   between cells of the tissue and the blood in the capillary

Capillary blood pressure

6.2.U5 Veins collect blood at low pressure from the tissues of the body and return it to the atria of the heart

Pressure graph for blood vessels

6.2.U6 Valves in veins and the heart ensure circulation of blood by preventing backflow

Valves in the heart and veins

6.2.U7 There is a separate circulation to the lungs

Blood circulation to the lungs

6.2.U8 The heart is initiated by a group of specialized muscle cells in the right atrium called the sinoatrial node

Valves in the heart and veins

6.2.U9 The sinoatrial node acts as a pacemaker

SA node is the pacemaker

6.2.U10 The sinoatrial node sends out an electrical signal that stimulates contraction as it is propagated through the walls                   of the atria and then the walls of the ventricles

heart electrical system link heart electrical system animation
Heart contractions

6.2.U11 The heart can be increased or decreased by impulses brought to the heart through the two nerves from                   the medula of the brain

Valves in the heart and veins

6.2.U12 Epinephrine increases the heart rate to prepare for vigorous physical activity

Epinephrine affects on heart rate

Applications

6.2.A1 William Harvey's discovery of circulation of the blood with the heart acting as a pump

Harvey's discovery of circulation of the blood

6.2.A2 Pressure changes in the left atrium, left ventricles and aorta during the cardiac cycle

Pressures changes in the heart diagram

6.2.A3 Causes and consequences of occlusion of the coronary arteries

Formation of an occlusion in a coronary artery

Skills

6.1.S1 Identification of the blood vessels as arteries, capillaries or veins from the structure of the walls

Identify all the blood vessels shown in the diagram below

Place your mouse on the diagram to view the identity of the vessels

Identify the different vessels

6.1.A2 Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts                   or in a diagram of heart structure

Identify all the structures shown in the diagram below

Place your mouse on the diagram to view the labels of the structures

Structures of the heart: blank and labelled
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