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From digestion to transport

From digestion to transport. What is being transported by the circulation?. Water Mineral ions Plasma proteins Products of digestion Hormones Vitamins Excretory products Cells. What are the components of your transport system?. The heart The blood vessels Blood…

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From digestion to transport

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  1. From digestion to transport

  2. What is being transported by the circulation? • Water • Mineral ions • Plasma proteins • Products of digestion • Hormones • Vitamins • Excretory products • Cells

  3. What are the components of your transport system? • The heart • The blood vessels • Blood… Watch them work together…

  4. The transport system

  5. Blood is the transport medium

  6. The heart is the pump

  7. Mammalian 4-chambered hearts develop from 3-chambered hearts

  8. Open circulation

  9. Fish circulation

  10. Frog circulation

  11. Our mammalian cardiovascular system is a double circulation

  12. The cardiovascular system is a double circulation (2)

  13. Our mammalian system is a double circulation (3)

  14. Systemic circulation Transports oxygenated blood to all of our tissues Returns low-oxygen blood to the right side of the heart

  15. The systemic circulation The systemic circulation is HIGH PRESSURE

  16. The pulmonary circulation

  17. The pulmonary circulation The PULMONARY circulation is LOW PRESSURE

  18. Blood vessels Basic animation of blood vessels

  19. How does the heart work as a double-circulation pump?

  20. Let’s draw a heart! • Drawing a heart...

  21. The heart muscle is nourished by the coronary arteries

  22. Control of heart rate Think of some reasons why heart rate might increase or decrease

  23. Control of blood pressure • Think of some reasons why blood pressure might rise or fall?

  24. Some factors which increase blood pressure

  25. The sino-atrial node is the major pacemaker of the heart

  26. Heart rate and force of contraction are controlled by the medulla (brainstem) • Cardio-accelerator centre – cardiac nerve: increases heart rate (epinephrine) • Cardio-inhibotorycentre – vagus nerve – decreases heart rate (Ach)

  27. The medulla responds to many factors An increase in carbon dioxide tension in the blood is sensed by chemoreceptors in the heart and carotid artery, and sent to the medulla for processing…

  28. The sino-atrial node is affected by both sympathetic (adrenaline/noradrenaline) and parasympathetic (Ach) fibres

  29. Catecholamine receptors

  30. The heart beats regularly…all by itself! • control of the cardiac cycle • conducrtion system of the heart

  31. Explain the basic cardiac cycle… • Animation 1 • slightly more detailed cardiac cycle

  32. Cardiac output • Cardiac output = volume of blood pumped by the heart in L/minute. • Cardiac output is is the product of HEART RATE (BEATS/MINUTE) and STROKE VOLUME (ML/BEAT) • CO can be increased by means of increasing heart rate OR stroke volume

  33. Tissue oxygen delivery:‘the bottom line’ • depends on cardiac output (cardiac function and forward flow) and arterial oxygen content (CaO2) • Oxygen delivery (DO2) = cardiac output multiplied by the oxygen content of blood DO2= CO X [Hb] X SpO2 X 1.34 (each 1 g of haemoglobin can carry 1.34 g of oxygen)

  34. Veins often have valves Veins have thinner, less muscular walls than arteries • They have wider lumens, to make blood flow easier • They have valves in them to stop blood flowing backwards • The pumping action of leg muscles also helps drive venous blood back towards the heart

  35. Venous and arterial emboli • When venous return is impaired (e.g. long time spent sitting and not moving), blood flow can slow down in certain veins. • A clot may then form, called an embolus • If the clot breaks and moves to the lungs, it can block in the pulmonary arterioles – pulmonary embolism, which can cause death Serena Wiliams pulmonary embolism

  36. Each organ has its own blood supply (arterial and venous) [the liver has two] • how does blood enter and leave the liver? • The hepatic artery provides oxygen-rich blood • The portal vein supplies blood rich in nutrients, draining from the digestive tract and pancreas

  37. Blood is composed of cells and plasma

  38. Plasma • water • products of digestion – sugars, amino acids, glycerol, fatty acids • hormones • vitamins • antibodies

  39. Cellular components of blood • Red blood cells: 5 – 6 million/ml • Platelets – clotting • White cells (leukocytes): 2-3% of total blood volume Lymphocytes – immune response Neutrophils - phagocytes

  40. Red blood cells (erythrocytes) • No nucleus (pack in more oxygen!) • Short lifespan (4 months) • red cell colourfrom haemoglobin protein – oxidised iron • Biconcave disc shape optimises surface area • Tiny!- easy to squeeze • Old cells are broken down in the liver, spleen and bone marrow

  41. White cells fight infection • White cells are made in the bone marrow • They have nuclei • There are many different types • Key types are PHAGOCYTES (eaters) and lymphocytes (immune cells)

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