THE BLOOD

• Every two seconds, someone in the U.S. needs a blood transfusion
• Blood


  Red, sticky, salty, and kind of metallic tasting
• Blood


  Accounts for about 8% of your body weight
• Blood


  • A type of connective tissue, made of living cells suspended in a nonliving matrix (plasma)
  • Transports and distributes oxygen, nutrients, waste products, and hormones around the body
  • Helps regulate and maintain body temperature, pH levels, and the volume of fluids in your body
  • Protects you from infection and from the loss of blood itself
• Blood is the one component of your body that we haven't figured out how to reproduce, synthesize, or imitate
• Blood donation process


  1. Get finger pricked

  2. Directed to lounge chair

  3. Inner elbow swabbed with alcohol

  4. Needle inserted to fill blood bag

  5. Unhooked and given cookie and juice
• Whole blood


  Mixture of cells and cell fragments (formed elements), water, and dissolved molecules
• Components of whole blood

  • Erythrocytes (red blood cells)
  • Leukocytes (white blood cells)
  • Platelets
  • Plasma
• Erythrocytes (red blood cells)

  Carry oxygen and carbon dioxide, make up about 45% of total blood volume
• Leukocytes (white blood cells)


  Defend the body from toxins and foreign microbes
• Platelets


  Cell fragments that help with blood clotting, make up less than 1% of blood volume
• Plasma


  Yellowish fluid that accounts for about 55% of blood volume, 90% water with 100 different solutes including proteins, electrolytes, gases, hormones, and waste products
• Electrolytes


  Positively-charged cations (calcium, sodium, potassium) and negatively-charged anions (phosphate, sulfate, bicarbonate) that help regulate blood chemistry
• Plasma proteins


  Most abundant solutes in plasma, including albumin, alpha and beta globulins, gamma globulin antibodies, and fibrinogen
• Hemostasis


  1. Blood vessel constricts to slow flow

  2. Platelets gather at injury site to form plug

  3. Fibrin threads reinforce clot and pull wound closed

  4. Blood vessel heals and clot dissolves
• Hemophilia


  Disorder where patient can't make effective fibrin clot, so they bleed longer
• Blood types


  • A, B, AB, O based on presence or absence of A and B antigens on red blood cells
  • Rh positive or negative based on presence or absence of Rh antigen
• Universal recipient


  AB blood type, has both A and B antigens so can accept any blood type
• Universal donor


  O blood type, has no A or B antigens so can donate to any blood type