Transport in humans

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  • - Recap digestive system
  • - Always return to these 3 main components of the circulatory system
  • - Students to read up pg 152
  • - Recap absorption of food in alimentary canal
  • - Explain the left and right
  • Another name for bicuspid valve is the mitral valve Do this after the lesson (given in summary sheet) with reference to notes and TB
  • Remind by spelling: Atria (a for all the things that are first) Ventricle (V after the a) For each slide, point out 1 thing about the picture
  • - Point out arrows
  • - Hole in the heart problem
  • Introduce ‘TB’ way of remembering (Semilunar valves named based on appearance; bicuspid and tricuspid based on the number of cusps) Tell students that these are simply ways of remembering , but do not need to be included in descriptions of the valves in essay/structure questions
  • Transport in humans

    1. 1. Transport in Humans
    2. 2. Learning outcomes • At the end of this topic, you should be able to Explain the importance of the circulatory system in linking all systems of the organism together Describe the structure and function of the heart in moving blood around the body Describe the structure and function of the blood vessels Describe the structure and function of the blood in supporting life
    3. 3. Lesson outline 1. What is a circulatory system? 2. Characteristics of our circulatory system 3. The heart 4. The blood vessels 5. The blood 6. Health problems in the circulatory system
    4. 4. 1. What is a circulatory system?
    5. 5. 1. What is a circulatory system? • Circulatory system = – A type of transport system, transporting substances around the body via the blood • Transport system = – Transports substances around the body – Can be via blood or lymph
    6. 6. 2. Characteristics of our circulatory system
    7. 7. 2. Characteristics of our circulatory system A. Why do we need a circulatory system? B. What are circulatory systems like? C. How is our circulatory system special?
    8. 8. 2. Characteristics of our circulatory system A. Why do we need a circulatory system? • Thinking time: – How are substances transported in simple, unicellular organisms? – We are complex, multicellular organisms Pg 139
    9. 9. 2. Characteristics of our circulatory system A. Why do we need a circulatory system? – All cells need to • Receive oxygen and nutrients • Remove waste products – Relying on diffusion alone to transport substances to all cells in multicellular organisms is • Not good enough • Not fast enough Pg 139
    10. 10. 2. Characteristics of our circulatory system A. Why do we need a circulatory system? – Cells in multicellular organisms are organized into systems • E.g. Digestive system • Cells  Tissues  Organs  Systems – A transport system is needed to carry substances from 1 part of the body to another Pg 139
    11. 11. 2. Characteristics of our circulatory system B. What are circulatory systems like? – Circulatory systems need 1. A transport fluid/medium 2. A pump to move the fluid along 3. A system of vessels in which the fluid moves = Heart = Blood vessels = Blood Pg 139
    12. 12. 2. Characteristics of our circulatory system B. What are circulatory systems like? – Our circulatory system consists of 1. The heart 2. Arteries 3. Arterioles 4. Blood capillaries 5. Venules 6. Veins The blood vessels (more later) Pg 152
    13. 13. 2. Characteristics of our circulatory system B. What are circulatory systems like? – Open circulatory systems • Blood (transport fluid) leaves blood vessels and comes into contact with body tissue • Found in arthropods e.g. insects, spiders and crabs • Nutrients obtained directly from blood surrounding organs • BUT, movement of blood is slow and poorly controlled • AND, blood supply is not regular or guaranteed, so organisms can only grow to limited size Pg 151
    14. 14. 2. Characteristics of our circulatory system B. What are circulatory systems like? – Closed circulatory systems • Blood does not leave blood vessels or come into contact with body tissues • Found in humans and all vertebrates (with backbone) • Better control of movement of blood (pump) • Regular and guaranteed supply of blood (pump) Pg 151
    15. 15. 2. Characteristics of our circulatory system C. How is our circulatory system special? – The transport system in mammals is divided into • Blood system carries blood • Lymphatic system carries lymph Pg 139
    16. 16. 2. Characteristics of our circulatory system C. How is our circulatory system special? – Double circulation • In all mammals • The blood passes through the heart twice in 1 complete circuit Pg 155, 156
    17. 17. 2. Characteristics of our circulatory system C. How is our circulatory system special? – Pulmonary circulation • Blood from heart to lungs and back • Pulmonary arteries: Heart  lungs • Pulmonary veins: Lungs  heart, oxygenated blood – Systemic circulation • Blood from heart to rest of body • Arteries: Heart  rest of body (except lungs), oxygenated blood • Veins: Body  Heart, deoxygenated blood Lungs Round the body Pg 155, 156 LR
    18. 18. 3. The Heart
    19. 19. 3. The Heart A. Structure and Function of the heart B. The Path blood takes through the heart C. The Cardiac Cycle D. Blood Pressure
    20. 20. 3. The Heart A. Structure and Function of the Heart – Size: About the same as a clenched fist – Shape: Roughly conical – Location: Behind the chest bone Between the two lungs • Inside pericardium (double membrane with fluid in between) Function: helps to reduce friction when heart is beating Pg 157
    21. 21. 3. The Heart A. Structure and Function of the Heart – You need to be able to label: Semi-lunar valve Semi-lunar valve Pg 157, 158
    22. 22. 3. The Heart A. Structure and Function of the Heart – 4 chambers – 2 on each side • Function: double circulation – Upper chambers: atria (singular: atrium) – Lower chambers: ventricles – Dividing wall: median septum • Function: prevent mixing of oxygenated and deoxygenated blood Pg 157
    23. 23. 3. The Heart A. Structure and Function of the Heart – Atria (Singular: atrium) • Blood moves from atria to ventricles • Relatively thinner muscular walls • Function: Forces blood into ventricles Pg 157
    24. 24. 3. The Heart A. Structure and Function of the Heart – Ventricles • Blood moves from ventricles out of the heart • Relatively thicker muscular walls • Function: Left ventricle (pumps blood around body) is thicker than right (pumps blood to lungs) Pg 157
    25. 25. 3. The Heart A. Structure and Function of the Heart – 2 sides separated by median septum – Left side: Oxygenated blood – Right side: Deoxygenated blood • ‘Hole in the heart’ Pg 157
    26. 26. 3. The Heart B. The Path blood takes through the heart – Blood passes from the atria to ventricles via the valves • Flaps of tissue • Function: Prevent backflow of blood • So that blood flow is unidirectional Pg 158
    27. 27. 3. The Heart B. The Path blood takes through the heart – Valves: 2 types in the heart 1. Atrioventricular = tricuspid [3 cusps] (right) + bicuspid [2]/mitral (left) 2. Semilunar (half-moon, see ) Pg 158
    28. 28. 3. The Heart B. The Path blood takes through the heart – Valves have chordae tendinae • Cord-like tendons • Function: To prevent valves from inverting Pg 158
    29. 29. 3. The Heart B. The Path blood takes through the heart – Label the parts of the heart in your handout – You will need to refer to it as we go through this section Pg 158
    30. 30. 3. The Heart B. The Path blood takes through the heart 1. We will start in the right atrium • This receives de-oxygenated blood from the rest of the body (except lungs) • Via the superior and inferior vena cava Pg 158
    31. 31. 3. The Heart B. The Path blood takes through the heart 1. The right atrium contracts • Tricuspid valves open 3. De-oxygenated blood flows into the right ventricle Pg 158
    32. 32. 3. The Heart B. The Path blood takes through the heart 4. The right ventricle contracts • Tricuspid valves close • Semilunar valves open • Closing and opening: due to blood pressure 5. The right ventricle relaxes • Semilunar valves close Pg 158
    33. 33. 3. The Heart B. The Path blood takes through the heart 6. Meanwhile, blood leaves for the lungs • Right ventricle walls thinner than left • Less force needed to pump blood to lungs • Via pulmonary artery • Blood travels more slowly than in aorta Pg 158
    34. 34. 3. The Heart B. The Path blood takes through the heart – Why is it good that blood travels more slowly in the pulmonary artery than in the aorta? Pg 158
    35. 35. 3. The Heart B. The Path blood takes through the heart 7. Blood from the lungs returns to the left atrium • Oxygenated blood • Via the pulmonary veins Pg 158
    36. 36. 3. The Heart B. The Path blood takes through the heart 8. The left atrium contracts • Bicuspid valves open 9. Oxygenated blood flows into the left ventricle Pg 158
    37. 37. 3. The Heart B. The Path blood takes through the heart 10.The left ventricle contracts • Bicuspid valves close • Semilunar valves open 11.The left ventricle relaxes • Semilunar valves close Pg 158
    38. 38. 3. The Heart B. The Path blood takes through the heart 12.Blood leaves for the rest of the body • Via the aorta • Thicker walls; more force needed to pump blood – Coronary arteries • Branch off from aorta • Bring O2 and nutrients to heart muscles Pg 158
    39. 39. 3. The Heart B. The Path blood takes through the heart – As blood travels along the aorta • Other arteries will branch off • Bring O2 and nutrients to other tissues Pg 158
    40. 40. 3. The Heart B. The Path blood takes through the heart – Steps 1 -6: • Right side of heart • De-oxygenated blood – Steps 7-12: • Left side of heart • Oxygenated blood Pg 158
    41. 41. 3. The Heart B. The Path blood takes through the heart – Steps 1-6 and 7-12 • Are happening simultaneously • Left and right atria contract together • Then left and right ventricles contract together Pg 158
    42. 42. 3. The Heart C. The Cardiac Cycle Pg 159
    43. 43. 3. The Heart C. The Cardiac Cycle – There are 4 stages • Corresponding to steps in the path of blood through the heart • Occurs in left and right sides simultaneously • Stage 1: (Step 1 / 7) • Stage 2: (Steps 2 and 3 / 8 and 9) • Stage 3: (Step 4 / 10) • Stage 4: (Step 5 and 6 / 11 and 12) – Stage 4 returns the heart to Stage 1 Pg 159
    44. 44. 3. The Heart C. The Cardiac Cycle 1. Both atria and ventricles relaxed – Blood flows into atria • Right side: from vena cavae • Left side: from pulmonary veins Pg 159
    45. 45. 3. The Heart C. The Cardiac Cycle 2. Atria contract; blood goes into ventricles – Atrioventricular (Tricuspid & bicuspid) valves are already open • Pressure in ventricles < pressure in atria Pg 159
    46. 46. 3. The Heart C. The Cardiac Cycle 1. Then ventricles contract (= ventricular systole) – Blood pressure in ventricles increases • Atrioventricular valves forced to close (‘lub’ sound) – Blood pressure in ventricles > Blood pressure in aorta • Semilunar valves forced open • Blood flows out of ventricles Pg 159
    47. 47. 3. The Heart C. The Cardiac Cycle 4. Ventricles relax (= ventricular diastole) – Blood pressure in ventricles decreases • Semilunar valves close (‘dub’ sound) • Atrioventricular valves open again Pg 159
    48. 48. 3. The Heart C. The Cardiac Cycle – Repeat stages 1-4! – Atria and ventricles work alternately Pg 159
    49. 49. 3. The Heart C. The Cardiac Cycle – Heartbeat – 1 Heartbeat = 1 Systole + 1 Diastole • (ventricular contraction and relaxation respectively) – Marked by the ‘lub’ and ‘dub’ sounds – 0.8 seconds – Short pause between heartbeats – Average: 72 times/min Pg 159
    50. 50. 3. The Heart C. The Cardiac Cycle – Heartbeat – What does your heartbeat rate depend on? – It varies with • Age • Size • Health Pg 159
    51. 51. 3. The Heart D. What is blood pressure? – It is the force that blood exerts on the walls of blood vessels – Unit: millimetres (mm) of mercury • mmHg – Instrument: sphygmomanometer
    52. 52. 3. The Heart D. What affects blood pressure? 1. Within the body a) Varies in different parts of the body • In the circulatory system, • Where is blood pressure highest? • Where is blood pressure lowest? b) Varies at different stages in the cardiac cycle • In the arteries, • When is blood pressure highest?
    53. 53. 3. The Heart D. What affects blood pressure?
    54. 54. 3. The Heart D. What affects blood pressure? 2. Between people – Varies with • Age • Physical activity • Emotion • Environment
    55. 55. 3. The Heart – Blood pressure D. Pressure changes in the heart – You need to remember the stages of the cardiac cycle, as pressure changes are due to • Contraction of atria/ventricles • Opening and closing of valves Left side –oxygenated blood Atria Ventricle Bicuspid valve Semilunar valve 1 Relaxed Relaxed Open Closed 2 Contracts Relaxed Open Closed 3 Relaxed Contracts Closed Open 4 Relaxed Relaxed Open Closed
    56. 56. 3. The Heart – Blood pressure D. Pressure changes in the heart Pg 161
    57. 57. 3. The Heart – Blood pressure D. Pressure changes in the heart – Let’s look at the left side (oxygenated blood) first – You can colour over the different lines in your notes Blue: Pressure in atrium Green: Pressure in ventricle Red: Pressure in aorta Pg 161
    58. 58. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart – You must know what the different graphs look like • You may get a question about only 1 of the graphs • Or you may be asked to label and describe the different graphs – Let’s look at the left side (oxygenated blood) first Pg 161
    59. 59. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 1. – Pressure in the left atrium increases slightly when it contracts – This causes ventricular pressure to also increase slightly as blood enters – Bicuspid valves are open Pg 161
    60. 60. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 2. – Pressure in the left ventricle increases sharply as it starts to contract – Once ventricular pressure > atrial pressure, bicuspid valve closes to prevent backflow of blood Pg 161
    61. 61. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 3. – When ventricle pressure > aorta pressure, semilunar valve opens – Aorta pressure increases, but later decreases as blood is moved away – Rate of increase of ventricular pressure slows Pg 161
    62. 62. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 1. – Ventricle begins to relax, causing semilunar valve to close to prevent backflow of blood – Atrial pressure begins to increase as blood starts flowing in again Pg 161
    63. 63. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 5. – Left ventricle remains relaxed – Ventricular pressure decreases further Pg 161
    64. 64. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 6. – Once ventricular pressure < atrial pressure, bicuspid valves open again Pg 161
    65. 65. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 7. – Both left atria and ventricle are relaxed – Blood flows into ventricle – Ventricular pressure gradually increases again Pg 161
    66. 66. 3. The Heart – Blood pressure D. Pressure changes in the LEFT side of the heart 8. – Cardiac cycle repeats itself Pg 161
    67. 67. 3. The Heart – Blood pressure D. Pressure changes in the heart – Let’s look at the right side (de-oxygenated blood) now – Pattern of pressure changes is similar (look at your handout) – BUT much smaller magnitude
    68. 68. 4. The Blood Vessels
    69. 69. 4. The Blood Vessels • We will be looking at 1. Arteries – Arteriole = small artery 1. Veins – Venule = small vein 1. Capillaries Pg 153
    70. 70. 4. The Blood Vessels • Function – To transport blood around the body • Structure of arteries and veins – Wall has 3 layers • Endothelium (innermost layer, 1 cell thick) • Middle layer (Smooth muscle + Elastic fibres) • External layer (Connective tissue) – Lumen • Space enclosed by the wall Pg 153, 154
    71. 71. 4. The Blood Vessels - Arteries • Definition: Blood vessels that carry blood AWAY from the heart • Structure – Thick, muscular and elastic walls – Elastic wall much thicker in arteries near the heart – No valves – Lumen smaller than that of vein with same diameter Pg 153, 155
    72. 72. Questions • What is the function of the smooth muscle? • What is the function of the elastic tissue? • What would happen if the arteries were less elastic?
    73. 73. 4. The Blood Vessels - Arteries • Function – To withstand immense pressure of blood as it is forced out of the heart – Elastic fibres enable artery wall to stretch and recoil (Recoil = spring back) so that blood is pushed along the artery in spurts – Smooth muscle contracts • Artery constricts (lumen narrower, less blood/unit time) – Smooth muscle relaxes • Artery dilates (lumen wider, more blood/unit time) Pg 153, 155
    74. 74. Thinking question • How does pulse come about?
    75. 75. 4. The Blood Vessels - Arteries • Related to heartbeat – When you feel your pulse, you are feeling the recoil of artery walls – Ventricular contraction (systole)  Arteries dilate – Ventricular relaxation (diastole)  Arteries recoil – Helps blood to move along arteries in a series of waves (Pulse wave) • Heart pumping is not the only mechanism Pg 153, 162
    76. 76. 4. The Blood Vessels - Arteries • Main arteries of the body – Pulmonary artery – Aorta/aortic arch • Arteries to the head, neck & arms • Dorsal aorta (continues on) • Hepatic artery (to liver) • Arteries to stomach & intestines • Renal arteries (1/kidney) • Arteries to legs Pg 162
    77. 77. What can happen if there is a fault to the veins?
    78. 78. 4. The Blood Vessels - Veins • Definition: Blood vessels that carry blood BACK to the heart • Structure – Middle wall layer much thinner • Less muscular • Less elastic tissue – Has semilunar valves – Skeletal muscles present around the veins – Lumen larger than that of artery with same diameter Pg 154, 155
    79. 79. Questions • Compare and contrast arteries and veins – In terms of wall thickness, presence of valves, lumen diameter (Past year O level qn) • How do these differences relate to their functions?
    80. 80. 4. The Blood Vessels - Veins • Function – Blood flow slower and smoother • Much lower blood pressure – Semilunar valves • Prevent backflow of blood – Skeletal muscles • Increase pressure exerted on the veins • Help move blood along more quickly Pg 154, 155
    81. 81. 4. The Blood Vessels - Veins • Main veins of the body – Pulmonary veins [to left atrium] – Superior vena cava [from head, neck and arms to right atrium] – Inferior vena cava [from rest of body to right atrium] • Hepatic veins (from liver) • Hepatic portal vein (from stomach and intestines, to liver) ‘Portal’ carries blood from 1 capillary network to another • Renal veins (from kidneys) Pg 163
    82. 82. 4. The Blood Vessels - Capillaries • Definition: Microscopic thin-walled blood vessels that carry blood from an arteriole to a venule • Structure – Walls have 1 layer • Endothelium only • 1-cell thick • Small gaps between cells – Extensive network Pg 153, 164
    83. 83. Questions • Why is an extensive network of capillaries required? • By what mode of transport do capillaries carry out their function? • What is diffusion?
    84. 84. 4. The Blood Vessels - Capillaries • Function – Small gaps between cells • Allow white blood cells to squeeze through (more later) Pg 164, 165
    85. 85. 4. The Blood Vessels - Capillaries • Function – Transfer of substances to tissue cells – By diffusion – Down concentration gradient – Efficiency increased by 1. Extensive network 2. Narrow capillary lumen Pg 164
    86. 86. 4. The Blood Vessels - Capillaries • Function – Transfer of substances to tissue cells – Diffusion • From capillaries into tissue fluid to cells • Dissolved food substances • Dissolved oxygen Pg 164
    87. 87. 4. The Blood Vessels - Capillaries • Function – Transfer of substances to tissue cells – Diffusion • From cells into tissue fluid to capillaries • Dissolved waste products – Transported to excretory organs for removal Pg 164
    88. 88. 4. The Blood Vessels - Capillaries • Tissue fluid/intercellular fluid/interstitial fluid – Definition • Diluted blood plasma containing white blood cells, small solute molecules and ions – Formation • Blood plasma forced out of arterial end of capillaries – Function • Bathes the tissue cells, filling spaces between them • Carries substances in solution between tissue cells and blood capillaries Pg 164, 165
    89. 89. 4. The Blood Vessels - Capillaries • Tissue fluid/intercellular fluid/interstitial fluid – Is related to lymph • More tissue fluid is constantly leaving the capillaries • Forcing it into lymph capillaries • Forming lymph – Lymph vessels • Lymph capillaries join, forming larger and larger vessels • Empty contents into vena cava (to right atrium) • Contents return to blood plasma Pg 164, 165
    90. 90. 5. The Blood
    91. 91. 5. The Blood A. Structure and composition of blood – Plasma – Red Blood Cells – White Blood Cells – Platelets B. Blood groups C. Functions of blood – Transport – Protection – Organ transplant and tissue rejection
    92. 92. A. Structure and Composition of the blood • Microscope picture of blood smear – Different types of blood cells – Blood is a tissue because it contains cells (Cells make up a tissue. A tissue can contain different kinds of cells) Pg 140
    93. 93. A. Structure and Composition of the blood Blood 55% plasma 45% blood cells and platelets 90% water 10% dissolved substances Antibodies Digested food Mineral salts Proteins for blood clotting Excretory products (Pale yellowish liquid) Amounts kept relatively constant Pg 140
    94. 94. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Pg 141
    95. 95. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma = Erythrocytes = Leukocytes/leucocytes = Thrombocytes Pg 141-143
    96. 96. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Ave 5 million/cm3 of blood (varies with gender and health) - Produced by bone marrow - Each cell lives about 3-4 months - Destroyed in the ____________ - Haemoglobin broken down in the ______________ Pg 141
    97. 97. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Structure - What do you remember about its structure? (Recap: Cells, TB pg 25) Pg 141
    98. 98. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Structure - No nucleus (Function: more space for haemoglobin) - Haemoglobin pigment (Function: ) - Circular, flattened biconcave disc (Function: ) - Elastic, can become bell-shaped (Function: Squeeze through blood vessels) Pg 141
    99. 99. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Larger in size than erythrocytes, but fewer in number - Ave 5000-10000/cm3 of blood - Colourless (no haemoglobin) - Most are also produced by bone marrow Pg 142
    100. 100. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Structure - Irregular in shape - Has a nucleus - Can move and change shape (Function: ) Pg 142
    101. 101. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma 2 main types - Phagocytes (different types have different names) - Lymphocytes - Function: To help the body fight disease Pg 142
    102. 102. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Phagocytes - Structure: Nuclei have lobes and cytoplasm is granular - Function: Engulf, ingest and digest foreign particles - Lymphocytes - Structure: Nuclei are large and round (no lobes), cytoplasm is non-granular - Function: Produce antibodies Pg 142
    103. 103. A. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Not true cells - But classified with cells when talking about composition of blood - Membrane-bound fragments of cytoplasm - Produced by bone marrow - Function: Involved in blood clotting Pg 143
    104. 104. B. Blood groups • There are 4 possible blood groups – A – B – AB – O • It is important to know your blood group for blood transfusions – Needed when a lot of blood is lost due to injury or surgery – Require compatible blood groups to be successful Pg 143, 144
    105. 105. B. Blood groups - Antigens • Blood group is determined by erythrocytes – By proteins embedded in the erythrocyte cell membrane – Antigens • They are found on all red blood cells Pg 143, 144
    106. 106. B. Blood groups - Antigens • Antigens correspond to the blood groups – Antigens are represented by capital letters – There are only 2 antigens, A and B – There are 4 possible combinations - A and B B A O AB B A AntigenBlood group Pg 143, 144
    107. 107. B. Blood groups - Antibodies – Antigens are found on erythrocytes • Other components of blood respond to these antigens (compatibility) – Lymphocytes produce antibodies • Help to protect us against foreign particles • Recognize what ‘belongs to us’ • Antibodies are part of the 10% dissolved substances in plasma – Antibodies react with what is foreign to cause clumping/agglutination of foreign particles or cells Pg 143, 144
    108. 108. B. Blood groups - Antibodies • Antibodies – Are represented with small letters a and b – There are only 2 antibodies, but 4 possible combinations – Antibodies are able to recognize antigens of the same letter to cause clumping/agglutination Pg 143, 144
    109. 109. – People with blood group AB have no antibodies against antigens A and B (NOT that they have no antibodies at all) B. Blood groups - Antibodies a and b - a b - A and B B A O AB B A AntibodyAntigenBlood group Pg 143, 144
    110. 110. B. Blood groups – Blood transfusions • What about blood cells donated in blood transfusion? – Antibodies are able to recognize their own blood cells as ‘self’ – Donated blood cells are ‘foreign’
    111. 111. B. Blood groups – Blood transfusions a and bO -AB aB bA O (no antigens) AB (antigens A and B) B (antigen B) A (antigen A) Donor’s blood groupRecipient’s antibodies Recipient’s blood group
    112. 112. B. Blood groups – Blood transfusions • How come antibodies in the donor’s blood do not cause clumping of the recipient’s red blood cells? – It depends on the volume of blood Vol of blood from donor << Total vol of blood in recipient – Donor’s blood is greatly diluted so antibodies in the donor’s plasma will not have an effect on recipient’s erythrocytes Pg 145
    113. 113. Question • Mr. Tan had an accident and lost a lot of blood. He requires a blood transfusion. His blood group is A. Several people have come forward to offer to donate blood to him. His wife is blood group AB, his father is blood group B, while his brother is blood group O. • Who can he accept blood from and why? Use the table given to determine the answer • If Mr. Tan’s wife had been in the accident as well, could she have accepted blood from any of the other 2 donors? Why?
    114. 114. C. Functions of the blood • 3 functions – Transport – Protection • Protection against disease-causing organisms(phagocyctosis & blood clotting) • Antibody production Pg 146-150
    115. 115. C. Functions of the blood – 1. transport • Transport medium – plasma Blood 55% plasma 45% blood cells and platelets 90% water 10% dissolved substances Antibodies Digested food Mineral salts Proteins for blood clotting Excretory products (Pale yellowish liquid)
    116. 116. C. Functions of the blood – 1. transport • Transport medium – red blood cells – O₂ is carried by red blood cells • Red pigment haemoglobin (NOT an enzyme) has high affinity for O₂ • O₂ is released as blood passes tissues containing little oxygen. It then diffuses into tissue fluid to the tissue cells • As blood returns to lungs, haemoglobin combines with O₂ in oxygen-rich environment again Haemoglobin Oxyhaemoglobin O₂ from lungs O₂ to body tissues Pg 146-150
    117. 117. C. Functions of the blood – 2a. protection • Protection against disease-causing organisms – white blood cells – Phagocytes • Engulf, ingest and digest bacteria • Can also ingest dead body cells Pg 146-150
    118. 118. C. Functions of the blood – 2a. protection • Protection against disease-causing organisms – white blood cells – Lymphocytes • Produce antibodies when stimulated by bacteria entering the bloodstream, which can – Cause clumping/agglutination – Cause bacterial cell membranes to rupture – Neutralize toxins – Make viruses unable to bind to their host cells • Antibodies have long-term protection: they remain in the blood long after the infection is over Pg 146-150
    119. 119. C. Functions of the blood – 2b. protection • Blood clotting – Stopping of blood flow at a wound is due to clotting • Important to a) Seal the wound b) Prevent entry of bacteria – Is the 1st line of defence • If bacteria does enter the bloodstream, phagocytes and lymphocytes are the 2nd line of defence – Involves platelets, proteins and enzymes Pg 146-150
    120. 120. C. Functions of the blood – 2b. protection • Blood clotting – A multi-step process involving enzymes – Like in Nutrition, • There are inactive proteins that have to be activated • They have similar names e.g. prothrombin (enzyme) fibrinogen (NOT an enzyme) Pg 146-150
    121. 121. C. Functions of the blood – 2b. protection • Blood clotting Platelets and damaged tissue Thrombokinase Produce Inactive prothrombin Active enzyme Active prothrombin Converts Soluble fibrinogen Insoluble fibrin threads Converts Clot Entangle red blood cells at the wound, forming Pg 146-150
    122. 122. C. Functions of the blood – 2b. protection • Blood clotting – Does not normally occur in our blood vessels • Due to presence of heparin which prevents clotting • Heparin is produced in the liver – Thrombokinase released by platelets neutralizes the effect of heparin – Haemophilia • Condition where ≥1 parts of the clotting process are defective, so blood clotting cannot occur • Haemophiliacs can lose a lot of blood from simple injuries Pg 146-150
    123. 123. 6. Heart Disease
    124. 124. 6. Heart Disease • Heart disease = cardiovascular disease – cardio = heart – vascular = related to the vessels around the heart • Types of heart disease – Coronary heart disease • includes coronary artery disease, myocardial infarction (heart attack), thrombosis and angina – Irregular heart beat (arrhythmias) • Includes cardiac arrest
    125. 125. 6. Coronary Heart Disease (CHD) • While there are different kinds, they are all caused by blockage or narrowing of coronary arteries • Angina: (a feeling) – Chest pains due to lack of oxygen to cardiac muscle • Heart attack: (an event) – Blood flow to parts of the heart are blocked – Cardiac muscle does not receive oxygen and nutrients – Cardiac muscle dies (this is irreversible) – This can be fatal
    126. 126. 6. Causes of CHD • Cholesterol and saturated fats deposited on the inner surface (endothelium) of the arteries – Narrows the lumen – Increases blood pressure – Increases risk of blood clots (as inner surface of arteries is now rough, not smooth) • Thrombus = blood clot in the blood vessels • Thrombosis = having a blood clot in a blood vessel • Embolus = blood clot that is able to move within blood vessels and cause a blockage away from the original site
    127. 127. 6. Causes of CHD • Atherosclerosis – The hardening of arteries – Due to the response of the white blood cells to fatty deposits – One type of arteriosclerosis (hardening of any arteries, for many different reasons) – There is also arteriolosclerosis (hardening of arterioles)
    128. 128. 6. Causes of CHD • Blocked coronary arteries can start as early as childhood! – Unhealthy diet • High in cholesterol • High in fat – Smoking • Carbon monoxide and nicotine increase risk of heart disease – Lack of exercise
    129. 129. 6. Causes of CHD • Other factors can increase your risk of CHD – Gender – Age – Family history – Emotional stress – Lifestyle
    130. 130. 6. Risk of CHD • Doctors assess your risk by looking at your – Gender – Age – Family history – Cholesterol level – Blood pressure level – Weight (or height/weight ratio) – (See Risk Prediction chart)
    131. 131. 6. Risk of CHD Blood pressure/ Cholesterol Risk of heart disease
    132. 132. Preventing CHD • Healthy diet – Balanced – Low in cholesterol (LDL only, not HDL) – Low in saturated fats – Rich in fibre • Stress management • Stop smoking • Exercise • If already at risk – Medication e.g. statins lower cholesterol levels

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