Blood formation

• What type of tissue is blood classified as?

  Specialised connective tissue
• How is blood distributed throughout the body?

  It circulates through the heart, arteries, veins, and capillaries
• What percentage of body weight does blood constitute?

  1. 8%
• How much blood does a 70 kg man have approximately?

  ~5.6 liters
• What is the normal temperature of blood?

  38C
• What is the normal pH range of blood?

  1. 35–7.45 (slightly alkaline)
• What are the main components of blood?

  • Plasma (55% of blood)
  • Cellular/formed elements (45%)
  • Red blood cells (erythrocytes; 99%)
  • White blood cells (leukocytes; 1%)
  • Platelets (<1%)
• What is serum and how is it formed?

  Serum is the fluid remaining after blood clots and does not contain coagulation factors
• How many times more red blood cells are there compared to white blood cells in circulation?

  More than 500 times
• What are the types of blood cell production processes?

  • Erythropoiesis: Red blood cell production
  • Leukopoiesis: White blood cell production
  • Thrombopoiesis: Platelet production

  
• What stimulates erythropoiesis?

  Erythropoietin (EPO)

  
• What is the role of multipotent stem cells in haemopoiesis?

  They differentiate into different types of blood cells

  
• What are the primary sites of haemopoiesis during different life stages?

  • Prenatal: yolk sac, liver, spleen, lymph nodes
  • Children: marrow of long bones (femur, tibia)
  • Adults: pelvis, vertebrae, sternum, ribs
• How long do mature erythrocytes survive?

  ~120 days

  
• What vitamins and minerals are required for erythropoiesis?

  Vitamins B12, folate, amino acids, and iron
• What hormone increases platelet production?

  Thrombopoietin
• What happens to platelets after their average lifespan of 10 days?

  They are removed from circulation by tissue macrophages
• What determines a person's blood type?

  The presence of specific cell surface antigens on erythrocytes

  
• What are the two major groups of blood group antigens?

  • ABO antigens
  • Rhesus (Rh) antigens

  
• What happens if a person with Type A blood receives Type B blood?

  It can cause agglutination or hemolysis of red blood cells
• What is the process of blood grouping/typing before a transfusion?

  1. Determine blood types by identifying antigens
  2. Expose blood to anti-sera containing different antibodies
  3. Observe for agglutination
• What is cross-matching in blood transfusion?

  Mixing donor and recipient blood samples to check for agglutination
• What are the universal donor and recipient blood types?

  • Universal donor: Type O-
  • Universal recipient: Type AB+

  
• What is Rh incompatibility and its consequence?

  It occurs when an Rh- mother has an Rh+ fetus, leading to hemolytic disease of the newborn
• How can Rh incompatibility be treated during pregnancy?

  By administering anti-D antibodies to the mother
• What is the impact of treating Rh incompatibility with anti-D antibodies?

  • Reduces incidence of hemolytic disease by over 90%
• Antibodies (agglutinins) are specialised molecules produced by the immune system to attack foreign antigens
• Agglutination is the clumping together of cells or particles due to their interaction with specific antibodies
• Hemolysis is the destruction of red blood cells