The blood system
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 materials 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.
• 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 materials 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.
Skill: 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.
There is a separate circulation for the lungs - the pulmonary circuit (right side of heart, blue or deoxygenated) The systemic circuit send blood to the rest of the body organs and systems (left side of heart, red or oxygenated) Aim 6: A heart dissection is suggested as a means of studying heart structure. Understanding of the structure of the cardiovascular system has allowed the development of heart surgery. |
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Application: Causes and consequences of occlusion of the coronary arteries. Aim 8: The social implications of coronary heart disease could be discussed. |
The Intrinsic conduction system • The heart beat is initiated by a group of specialized 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. |
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Dr. Daniel Hale Williams (1856 - 1931) was the first cardiologist to successfully perform a tricky open heart surgery — the repair of the pericardium, the thin sac that encases the heart. His pioneering surgery occurred in the summer of 1893. James Cornish, who had been stabbed in the chest, was brought to Provident Hospital. In a room crammed with other doctors who were observing, he cut open the cartilage between Cornish's ribs and opened a "trapdoor" to the heart, according to Columbia's Department of Surgery. From there, he sutured a punctured artery and sewed the pericardium. Williams had no option for blood transfusion, so he rinsed the wound with salt solution and held the wound together with forceps. Cornish walked out of the hospital 51 days later, and he would live another 20 years. LiveScience, June 2020
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Theory of knowledge:
Our current understanding is that emotions are the product of activity in the brain rather than the heart.
Is knowledge based on science more valid than knowledge based on intuition?
Our current understanding is that emotions are the product of activity in the brain rather than the heart.
Is knowledge based on science more valid than knowledge based on intuition?