Red blood cells in Blood


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Red blood cells in Blood

  1. 1. Transport in Human
  2. 2. At the end of the lesson, you should be able to  State the functions of blood:  Red blood cells – haemoglobin which aids in oxygen transport  White blood cells – phagocytosis, antibody formation and tissue rejection  Platelets – fibrinogen to fibrin, causing clotting  Plasma – transport of blood cells, ions, soluble food substances, hormones, carbon dioxide, urea, vitamins, plasma proteins 2
  3. 3. What is Blood? Blood3 types of cells present in thehuman blood cell:• red blood cells (erythrocytes)• white blood cells (leukocytes) plasma, 55%• platelets (thrombocytes)Plasma is a liquid consisting91% water which has blood cells, 45%inorganic ions, nutrients,waste products, hormonesand soluble proteins dissolvedin it. 3
  4. 4. Red Blood Cells Blood Formed in bone marrows of long bones. Formed from nucleated cells called erythroblasts. Exposed to maximum surface area for the exchange of oxygen and carbon dioxide. 95% of the protein in red blood cell is haemoglobin and 5% of the protein are enzymes that allow the cell to survive for about 120 days. cytoplasm containing haemoglobin plasma membrane 4
  5. 5. Red Blood Cells Blood The binding of oxygen to haemoglobin is reversible. In the lungs, where oxygen concentration is high, oxygen combines with haemoglobin to form oxyhaemoglobin. When blood arrives at cells where the oxygen concentration is low, it unloads and becomes maroon haemoglobin once again. high oxygen concentration Hb + 4O2 Hb(O2)4 (haemoglobin) low oxygen concentration (oxyhaemoglobin) 5
  6. 6. Red Blood Cells Blood  As red blood cells pass through tissues, they pick up carbon dioxide.  Most of the carbon dioxide combines with water to form carbonic acid. CO2 + H2O H2CO3 carbonic acid  The carbonic acid then ionises to form hydrogen ions and hydrogen carbonate ions. H2CO3 H+ + HCO¯ 3 carbonic acid hydrogen hydrogen ion carbonate ion  About 70% of the ions leave the red blood cells and remain in plasma.  When the blood reaches the lungs, carbon dioxide is released and diffuses out of the blood to enter the alveoli.  Carbon dioxide is then breathed out. 6
  7. 7. What is anaemia? Lower red blood cell count Caused by deficiency in iron in diet leading to less haemoglobin being producedSymptoms: Easily tired, looks pale, breathless Who’s vulnerable? Pregnant ladies, people who have lost large amounts of blood
  8. 8. Why do people living in highaltitudes have rosy cheeks? Concentration of oxygen in air is lower Absorb insufficient oxygen for respiration Acclimatisation  Body produces more red blood cells  increase amount of haemoglobin per unit volume of blood Hence more oxygen can be transported to cells
  9. 9. Blood group Red blood cells carry special protein called antigens on their cell surfaces. Blood plasma contains antibodies. Blood groups are classified according to the antibodies and antigens present in their blood. There are four groups of blood, named A, B, AB and O. Each group is named after the antigen present. 9
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