Blood unit

• Blood


  Transports everything that must be carried from one place to another
• Things blood transports


  • Nutrients
  • Wastes
  • Hormones
  • Body heat
• Blood


  The only fluid tissue in the human body
• Blood


  • Classified as a connective tissue
• Components of blood


  • Living cells
  • Formed elements
  • Nonliving matrix
  • Plasma
• If blood is centrifuged

  1. Erythrocytes sink to the bottom (45 percent of blood, a percentage known as the hematocrit)

  2. Buffy coat contains leukocytes and platelets (less than 1 percent of blood)

  3. Plasma rises to the top (55 percent of blood)
• Buffy coat


  A thin, whitish layer between the erythrocytes and plasma
• Oxygen-rich blood


  Scarlet red
• Oxygen-poor blood


  Dull red
• Blood pH


  Must remain between 7.35 and 7.45
• Blood temperature


  Slightly higher than body temperature, at 100.4°F
• Healthy man's blood volume

  About 5-6 liters, or about 6 quarts
• Blood volume


  Makes up 8 percent of body weight
• Blood plasma


  Composed of approximately 90 percent water
• Before a blood transfusion, compatibility testing is done to ensure the recipient receives the correct blood type.
• Transfusions are crucial for various medical conditions like severe anemia, surgery, and trauma.
• The ABO system has four major blood types: A, B, AB, and O.
• Antigens are substances that cause an immune response when introduced into the body.
• Blood plasma

  • composed of approximately 90 percent water
  • Includes many dissolved substances: Nutrients, Salts (electrolytes), Respiratory gases, Hormones, Plasma proteins
• Blood Plasma


  Plasma proteins are the most abundant solutes in plasma, most of which are made by the liver
• Plasma proteins


  • Albumin-regulates osmotic pressure
  • Clotting proteins-help to stem blood loss when a blood vessel is injured
  • Antibodies-help protect the body from pathogens
• Acidosis


  Blood pH becomes too acidic
• Alkalosis


  Blood pH becomes too basic
• Restoring blood pH to normal

  Respiratory system and kidneys help
• Formed Elements


  • Erythrocytes (red blood cells, or RBCs)
  • Leukocytes (white blood cells, or WBCs)
  • Platelets (cell fragments)
• Erythrocytes (red blood cells, or RBCs)

  • Main function is to carry oxygen
  • Biconcave disks
  • Essentially bags of hemoglobin
  • Anucleate (no nucleus)
  • Contain very few organelles
  • Normal count is 5 million RBCs per cubic millimeter of blood
• Hemoglobin


  Iron-containing protein that binds strongly, but reversibly, to oxygen
• Formed Elements

  • Hemoglobin
  • Iron-containing protein
  • Binds strongly, but reversibly, to oxygen
  • Each hemoglobin molecule has four oxygen binding sites
  • Each erythrocyte has 250 million hemoglobin molecules
  • Normal blood contains 12-18 g of hemoglobin per 100 mL of blood
• Red blood cells (RBCs)

  • Carry oxygen
  • Abnormal shapes can lead to anemia
• Formed Elements


  The cellular components of blood
• Anemia


  • Decrease in the oxygen-carrying ability of the blood
• Sickle cell anemia (SCA)

  Results from abnormally shaped hemoglobin
• Polycythemia


  Excessive or abnormal increase in the number of RBCs
• Polycythemia


  • Caused by bone marrow cancer (polycythemia vera)
  • Caused by life at higher altitudes (secondary polycythemia)
  • Increases blood viscosity and slows blood flow
• Leukocytes (white blood cells, or WBCs)


  • Crucial in body's defense against disease
  • Complete cells, with nucleus and organelles
  • Able to move into and out of blood vessels (diapedesis)
  • Move by amoeboid motion
  • Respond to chemicals released by damaged tissues (known as positive chemotaxis)
• Normal WBC count is 4,800 to 10,800 per cubic millimeter of blood
• Leukocytosis


  WBC count above 11,000 cells/mm³, generally indicates an infection
• Leukopenia


  Abnormally low leukocyte level, commonly caused by certain drugs
• Leukemia


  Bone marrow becomes cancerous, turns out excess WBCs
• Types of leukocytes


  • Granulocytes
  • Agranulocytes