Brent Cornell

     
Understandings:

• Arteries convey blood at high pressure from the ventricles to the tissues of the body
• Arteries have muscle cells and elastic fibres in their walls
• The muscle and elastic fibres assist in maintaining blood pressure between pump cycles
• Blood flows through tissues in capillaries
• Capillaries have permeable walls that allow exchange of material between cells in the tissue and the blood in the capillary
• Veins collect blood at low pressure from the tissues of the body and return it to the atria of the heart
• Valves in veins and the heart ensure circulation of blood by preventing backflow
• There is a separate circulation for the lungs
• The heart beat is initiated by a group of specialised muscle cells in the right atrium called the sinoatrial node
• The sinoatrial node acts as a pacemaker
• 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
• The heart rate can be increased or decreased by impulses brought to the heart through two nerves from the medulla of the brain
• Epinephrine increases the heart rate to prepare for vigorous physical activity

Applications:

• William Harvey’s discovery of the circulation of blood with the heart acting as a pump
• Pressure changes in the left atrium, left ventricle and aorta during the cardiac cycle
• Causes and consequences of occlusion of the coronary arteries

Skills:

• Identification of blood vessels as arteries, capillaries or veins from the structure of their walls
• Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure