TEST 2

• Functions of Blood


  1. Transport of gases, nutrients and waste products.

  2. Transport of process molecules

  3. Transport of regulatory molecules

  4. Regulation of pH and osmosis

  5. Maintenance of body temperature

  6. Protection against foreign substances

  7. Clot formation
• Where does the vitamin D precursor get transported?

  From skin to liver and kidneys
• Normal blood pH


  7.35-7.45
• Composition of Blood


  - Plasma (55%)

  - Red blood cells (45%)

  - Buffy coat, composed of white blood cells and platelets
• Plasma


  - Liquid part of blood

  - Proteins: Albumins, Globulins, Fibrinogen
• Colloid


  Found in plasma, contains suspended substances, 91.5% H2O, 8.5% gases, proteins, ions, nutrients, waste, regulatory substances
• Albumins


  Plasma -

  
  

  Most abundant, 58%, Osmotic pressure, transports fatty acids, bilirubin, thyroid hormones
• Globulins


  38% of plasma proteins, antibodies, transports lipids, iron and hormones
• Fibrinogen


  4% of plasma proteins; blood clotting
• Red Blood Cells (erythrocytes)


  - 95% of formed elements

  - Biconcave discs, no nucleus or mitochondria

  - Contain hemoglobin (protein) transports oxygen and CO2

  - Converts CO2 and H2O to carbonic acid (H2CO3)
• Size of RBCs


  5.4 million/microlitre - adult men

  
  

  4.8 million/microlitre - adult women
• Components of RBCs


  - 1/3 hemoglobin

  - 2/3 lipase, ATP, carbonic anhydrase
• Transport functions of RBCs (oxygen)


  - 98.5% bound to hemoglobin

  - 1.5% dissolved in plasma
• Transport functions of RBCs (CO2)

  - 23% bound to hemoglobin

  -7% dissolved in plasma

  - 70% as bicarbonate
• Transport functions of RBCs (protons)

  Generated from carbonic anhydrase (CA) reaction
• White Blood Cells (leukocytes)

  - 5% of formed elements

  - Granulocytes

  - Agranulocytes
• Granulocytes


  Large granules; have multi-lobed nuclei

  
  

  Three types: neutrophils, eosinophils, basophils
• Agranulocytes


  Small granules and nuclei that are not lobed

  
  

  Two types: lymphocytes and monocytes
• Platelets (thrombocytes)


  - Cell fragment

  - Form platelet plugs, release chemicals necessary for blood clotting
• Hematopoiesis


  Process of blood cell production
• Post birth hematopoiesis


  Occurs in the red bone marrow, lymphatic system
• Stem cell hematopoiesis


  All formed elements derived from single population - Hemocytoblast
• Proerythroblasts become


  RBCs
• Myeloblasts become


  o Basophils

  o Neutrophils

  o Eosinophils
• Lymphoblasts become


  Lymphocytes
• Monoblasts become


  Monocytes
• Megakaryoblasts become


  Platelets
• Hemoglobin


  Four globin molecules (polypeptide chains). Four heme molecules, each containing one iron atom: transport oxygen; transport carbon dioxide.
• Erythropoiesis


  - Production of red blood cells

  - Takes approximately 4 days

  - 2 million RBCs degenerated per second

  - 25 trillion RBCs in circulation

  - RBCs last 120 days in circulation
• Erythropoietin


  A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow.
• RBC Recycling


  1. Natural degeneration of RBCs

  2. Separation of components
• Components of RBCs that are separated

  Globin, heme, iron-free heme
• Globin


  Protein - recycling amino acids
• Heme


  Iron removed and recycled (liver, spleen, bone marrow)
• Iron-free heme


  Converted to bilirubin
• WBCs protect the body against

  microorganisms and remove dead cells and debris
• Are WBCs nucleated?


  No
• Do WBCs have hemoglobin?

  No
• Movements of WBCs


  - Ameboid movement

  - Diapedesis (emigration)

  - Chemotaxis
• Diapedesis


  Cells become thin, elongate and move either between or through endothelial cells of capillaries... WBCs leave the CV system