Transport in humans_blood vessels

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Transport in humans_blood vessels

  1. 1.
  2. 2. Chapter Overview<br />Transport in Mammals<br />8.2 The Blood & Blood vessels<br />8.1 The Circulatory System - Introduction & Anatomy<br />8.3 The Hear t & Cardiac Cycle<br />8.4 Heart Diseases<br />8.1.1 The need for transport<br />8.1.2 Double Circulation<br />8.3.1. Structure and Function of heart<br />8.3.2 Heart valves, Systole and Diastole<br />8.2.1 Components of the Tissue Fluid<br /> a) Blood Plasma<br /> b) Red Blood Cells<br /> c) White Blood Cells<br /> d) Platelets<br />8.2.2 Exchange of Substances and The Lymphatic System<br />8.2.3 Haemoglobin<br />8.2.4 Rejection and ABO Blood Group<br />8.2.5 Structure-function of blood vessels<br />8.4.1 Myocardial infarction<br />8.4.2 Causes of Heart Diseases<br />
  3. 3. Objectives<br /> Relate the structure of arteries, veins and capillaries to their functions.<br />(b) Describe the transfer of materials between capillaries and tissue fluid.<br />
  4. 4. TB PG 152<br />Organisation of Blood Vessels<br />Arteries  arterioles  capillaries venules veins<br />
  5. 5. TB PG 153<br />The Blood Vessels<br />There are 5 types of vessels in the mammalian circulatory system.<br />Arteries<br />Arterioles<br />Veins<br />Venules<br />Capillaries<br />
  6. 6. TB PG 153<br />The Blood Vessels<br />Arteries<br /><ul><li> Branches into smaller vessels called arterioles
  7. 7. Transports oxygenated bloodaway from the heart </li></ul>(except pulmonary artery)<br />Wavy elastic band<br />External layer(Loose connective tissue) <br />Middle layer (Smooth muscle & elastic fibres) <br />(Inner layer) Endothelium<br /> Lumen<br />
  8. 8. TB PG 153<br />Bigger Lumen<br />The Blood Vessels<br />Veins<br /><ul><li> Smaller vessels called venules come together to form vein
  9. 9. Carry deoxygenated bloodtowardsthe heart</li></ul>(except pulmonary vein)<br />External layer (loose connective tissue<br />Middle layer (Thinner smooth muscle and elastic fibre<br />Endothelium<br />
  10. 10. TB PG 164<br />Lumen<br />The Blood Vessels<br />Capillaries<br /><ul><li>Smallest vessels of all
  11. 11. Exchange of substances between blood and surrounding tissue (facilitated by one cell thick endothelium)</li></ul>One cell thick endothelium<br />
  12. 12. Types of blood vessels<br />arteries<br />capillaries<br />veins<br /><ul><li>Carry blood away from heart
  13. 13. Branches into smaller vessels called arterioles
  14. 14. Transports oxygenated bloodaway from the heart </li></ul>(except pulmonary artery)<br /><ul><li>return blood toheart
  15. 15. Smaller vessels called venules come together to form vein
  16. 16. Carry deoxygenated bloodtowardsthe heart</li></ul>(except pulmonary vein)<br /><ul><li>connect arteries to veins
  17. 17. Smallest vessels of all
  18. 18. Exchange of substances between blood and surrounding tissue (facilitated by one cell thick endothelium.</li></li></ul><li>TB PG 153<br />The Blood Vessels<br />Arteries Structure<br /><ul><li>3 layers of tissues
  19. 19. Endothelium </li></ul> (Tunica intima)<br /><ul><li>Smooth muscle & elastic fibres (Tunica media)
  20. 20. Loose connective tissue (Tunica externa)</li></li></ul><li>TB PG 153<br />The Blood Vessels<br />Arteries Structure<br /><ul><li>Thick elastic, muscular walls</li></ul> Arteries receive blood directly from the heart at high pressure<br /> To withstand high blood pressure, allowing them to receive blood from the heart.<br /><ul><li>Elasticitypermits stretching and recoiling of the artery wall. This helps to push the blood along
  21. 21. Smooth muscles contract or dilates </li></ul> lumen constrict or dilate thus controlling blood flow<br />
  22. 22. TB PG 153<br />The Blood Vessels<br />Constriction & dilation of an artery is brought about by the contraction& relaxationof the muscles in the arterial wall.<br />Arteries Structure<br /><ul><li> Round cross-sectional lumen
  23. 23. Smaller lumen than veins</li></ul> Due to presence of thicker layer of muscles<br />
  24. 24. TB PG 154<br />The Blood Vessels<br />VEIN<br />ARTERY<br />Veins Structure<br /><ul><li>3 layers of tissues
  25. 25. Less elastic, muscular walls
  26. 26. Presence of valves</li></ul>  prevent backflow of blood<br />
  27. 27. TB PG 154<br />The Blood Vessels<br />Veins Structure<br /><ul><li> Larger lumen compared to artery
  28. 28. Walls are less thick and muscular and contain less elastic tissue</li></ul> Blood is under lower pressure, so walls need not be as strong<br />
  29. 29. TB PG 154<br />The Blood Vessels<br />Veins Structure<br /><ul><li>Presence of semi-lunar valves</li></ul> Pressure in the veins is lower, so semi-lunar valves help prevent the backflow of blood<br />
  30. 30. MJR Biology Department<br />Vein<br />Semi-lunar valve<br />1. Muscles contract, push against the walls of the blood vessels<br />2. Narrowing of vein causes blood cells to be pushed forward<br />7/12/2010<br />16<br />
  31. 31. Varicose Vein<br /> Varicose veins are distended branches of the major veins in the leg. They become distended due to failure of the valves in the main veins which allows blood to fall back down the leg (reflux)<br />
  32. 32. Varicose Vein<br />Varicose veins are more common in women than in men, and are linked with heredity[6]. Other related factors are pregnancy, obesity, menopause, aging, prolonged standing, leg injury and abdominal straining. Varicose veins are bulging veins that are larger than spider veins, typically 3 mm or more in diameter<br />
  33. 33. TB PG 152<br />The Blood Vessels<br />Capillaries Structure<br /><ul><li> Walls are made up of only a single layer of flattened cells called endothelium. </li></ul> Facilitate Rapid Exchange of substances between blood and surrounding tissue<br /> <br /> Endothelium is selectively permeable – allows small substances to diffuse but not large substances.<br /> <br /> Blood pressure in capillary is low thus there is more time for the exchange of substances.<br />
  34. 34. TB PG 152<br />The Blood Vessels<br />Capillaries Structure<br /><ul><li>Highly branched</li></ul>  increase SA/V ratio compared to arteriole from which the branches originate.<br /><ul><li>Lower blood flow and blood pressure
  35. 35. Allow for more time for exchange</li></li></ul><li> Exchange of materials between the blood and the body cells<br />capillary<br />oxyhaemoglobin<br />cell<br />TB PG 164<br />white blood cells<br />water<br />O2<br />nutrients<br />plasma<br />waste products<br />CO2<br />tissue fluid<br />Diffuse across the capillary wall <br />Diffuse across the capillary wall <br />Squeeze through the wall <br />
  36. 36. TB PG 164<br />Cell<br />Transport function<br />Cell<br />Cell<br />Cell<br />Cell<br />RBC<br />Cell<br />RBC<br />Cell<br />Cell<br />Cell<br />Cell<br />Arteriole<br />Capillaries<br />Venule<br />Cell<br />Cell<br />Cell<br />Exchange of substances<br />Useful materials such as glucose and oxygen are transported from plasma /RBC (higher concentration) to tissue fluid (lower concentration), down a concentration gradient, by diffusion. The useful materials in the tissue fluid will diffuse to the cells when concentration of these useful materials in the tissue fluid becomes higher than that in the cells. Osmosis will also occur.<br />Cell<br />Cell<br />Cell<br />Cell<br />Cell<br />
  37. 37. TB PG 164<br />Cell<br />Transport function<br />Cell<br />Cell<br />Cell<br />Cell<br />RBC<br />Cell<br />RBC<br />Cell<br />Cell<br />Cell<br />Cell<br />Arteriole<br />Capillaries<br />Venule<br />Cell<br />Cell<br />Cell<br />Exchange of substances<br />Cell<br />Waste products such as carbon dioxide and urea are transported from cells (higher concentration) to tissue fluid (lower concentration), down a concentration gradient, by diffusion. The waste products in the tissue fluid will diffuse to the plasma when concentration of the waste products in tissue fluid is higher than plasma.<br />Cell<br />Cell<br />Cell<br />Cell<br />
  38. 38. TB PG 164<br />Venule end<br />Arteriole end<br />Formation of tissue fluid<br />What are the small or elastic molecules in blood?<br />What is the structure of capillaries?<br />Partially permeable<br />- Plasma (water + small soluble molecules) - WBC<br />What does partially permeable mean?<br />Allows small molecules to move through. Elastic molecules maybe able to squeeze through as well.<br />What are the big or less elastic molecules in blood?<br />- RBC - Plasma proteins<br />
  39. 39. TB PG 164<br />Water, small soluble molecules<br />Water, small soluble molecules and WBC<br />Venule end<br />Arteriole end<br />Water, small soluble molecules<br />Water, small soluble molecules and WBC<br />Red blood cells and big plasma proteins continue to move in the capillaries. As blood flows from the arteriole to venule end, the blood becomes concentrated with solutes, such as plasma proteins.<br />Water from tissue fluid moves into the blood by osmosis at the venule end and small soluble molecules move into the blood by diffusion.<br />High pressure at the arteriole end forces water, small soluble molecules and white blood cells out of capillaries through the partially permeable endothelium into the tissue fluid.<br />Formation of tissue fluid<br />Remaining tissue fluid is collected by lymphatic vessels. The fluid in lymphatic system is known as lymph. Lymph will be emptied to blood circulation through a vein near heart.<br />
  40. 40. Blood pressure in different blood vessels<br />
  41. 41.
  42. 42. Comparing the Blood Vessels<br />
  43. 43. Comparing the Blood Vessels<br />
  44. 44. The figure below shows three types of blood vessels (not drawn to scale) in the human body. Which of the following is true?<br />
  45. 45. Lymphatic System<br />Movement of Blood Plasma into Body Tissues<br /><ul><li>Blood in arterioles  Higher pressure than capillaries
  46. 46. Blood plasma hence forced to leave capillaries
  47. 47. And enter body tissues
  48. 48. Soluble proteins cannot pass through capillaries.
  49. 49. Hence the fluid that enters the body tissues does not contain these proteins.
  50. 50. This fluid is known as interstitial fluid or tissue fluid.</li></li></ul><li>Lymphatic System<br />Where does interstitial fluid goes?<br /><ul><li>Collected in lymph vessels.
  51. 51. Part of the lymphatic system.</li></li></ul><li>Lymphatic System<br />Where does interstitial fluid goes?<br /><ul><li>Returned back to bloodstream via left subclavian vein</li></li></ul><li>Vein<br />Artery<br />Adapted from http://www.und.nodak.edu<br />

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