Immune system

• Blood consists of 45% red blood cells, less than 1% white blood cells, and 55 % plasma.
• Red blood cells, or erythrocytes have a primary function of transporting oxygen.
• Each red blood cell has about 280 million Hemoglobin molecules.
• Hemoglobin consists of a heme (iron-containing pigment) and a globin (protein structure).
• Red blood cells are biconcave (concave on both sides), which provides a greater surface area for transporting oxygen.
• Red blood cells are enucleated (no nucleus), giving more room for hemoglobin.
• Red blood cell production starts in the marrow and begins as stem cells with a nucleus.
• Mature red blood cells that enter the blood stream have no nucleus.
• Red blood cells live 120 days.
• The outer membrane of red blood cells becomes brittle with age, causing them to rupture in the capillaries.
• Specialized white blood cells in the liver and spleen monitor the age of red blood cells.
• When oxygen levels get low, kidneys release REF (renal erythropoietic factor), which combines with liver globulins to make erythropoietin, starting red blood cell production.
• Individuals in high altitudes have higher counts of red blood cells to make up for the lack of oxygen.
• Anemia suffer from low energy levels due to low hemoglobin or red blood cells.
• Causes of anemia include hemorrhage, physical injury, bleeding ulcers or low iron.
• Leukocytes, or white blood cells, have a nucleus and are made in the bone marrow.
• There are two types of leukocytes: those with granules (granulocytes) and those without granules (agranulocytes), which are modified in the lymph nodes.
• Leukocytes' two main functions are to destroy invading microbes by phagocytosis and produce antibodies.
• Diapedesis is the process where white blood cells squeeze through gaps in capillaries.
• White blood cells engulf microbes and release enzymes to digest microbes and cells, remaining proteins, and dead cells, resulting in pus.
• Platelets?

  • Platelets do not contain a nucleus
  • Also called thrombocytes
  • Produced in the bone marrow
  • Play an important role in clotting
  • Platelets stick to injured sites.....forming a plug  (stops the bleeding)
  • platelets change shape (round to spiky)

  they release substances that trap more platelets
• Plasma 

  (~55 %)

  
  

  Structure

  • 90 % water
  • 10 % glucose, proteins, vitamins/minerals, wastes, gases

  Function

  • maintains blood volume
  • proteins for homeostasis

  Other

  • proteins – globulin, albumin, fibrinogen
• RBC’s (~45 %)Structure

  • contains hemoglobin…280 million on one RBC (heme is iron, globin is protein)
  • no nucleus
  • biconcave disks
  • live ~ 120 days
  • produced in bone marrow

  Function

  • carry oxygen
  • hemoglobin + O2 forms oxyhemoglobin
  • also carries CO2
  • hemoglobin + CO2 forms carbaminohemoglobin Other
  • anemia is a ↓ in RBC’s
  • injury ↓ RBC’s
  • high altitude – need more RBC’s because less O2
• WBC’s 

  (<1 %)

  Structure

  • do have a nucleus
  • larger than RBC’s
  • several types
  • produced in bone marrow Function
  • destroy foreign invaders
  • produce antibodies
  • produce pus
  • perform phagocytosis Other
  • AIDS
  • leukemia 
  • ↑ WBC’s during infection
• Platelets (<<1%)Structure

  • no nucleus
  • irregular shape, fragile
  • produced in bone marrow

  Function

  • initiate blood clotting reactions when ruptured Other
  • hemophilia
• Blood Clotting

  • Prevents blood loss

  Steps

  1. Platelets stick to injured site (They release thromboplastin)
  2. Thromboplastin activates a plasma protein prothrombin (produced in the liver)
  3. Prothrombin is transformed to thrombin
  4. Thrombin acts as an enzyme and slices a plasma protein fibrinogen (produced in the liver)
  5. Fibrinogen gets converted to fibrin threads
  6. These fibrin threads wrap around the damaged area
  7. Red blood cells and more platelets become trapped
• Blood clotting saves your life but it can also be life-threatening.
• Block clots can block blood vessels = Thrombus.
• If block clots occur in the brain = Stroke.
• Embolus: a dislodged clot can travel throughout and become lodged in a vital organ, this is life threatening.
• Examples of embolus include Cerebral embolism (brain), Coronary embolism (heart), Pulmonary embolism (lungs).
• Fluosol is an artificial blood that is a non-toxic liquid that contains fluorine.
• Advantages of Fluosol include that it requires no blood matching, can be stored for long periods of time, and does not need to be screened.
• Disadvantages of Fluosol include that it cannot form clots and it offers no immunity.
• Humans can have one of four distinct blood types: A, B, AB, O.
• Blood types are inherited.
• Glycoproteins attached to the cell membrane of red blood cells determine blood type.
• Type A has the A glycoprotein/marker/antigen.
• Type B has the B glycoprotein/marker/antigen.
• Type AB has both A marker & B marker and is the universal recipient.