Blood Lab Overview

Lab 1: Blood

Readings

  • Pages: 415-433
  • Exercise: 29A Blood

Objectives:

  1. Composition of Blood: Distinguish between formed elements and plasma.
  2. Blood Smears: Identify different blood cells and platelets; know basic function(s) of each type.
  3. Hematocrit: Perform the test and understand normal/abnormal ranges; knowledge of buffy coat.
  4. Bleeding Time and Clotting Time: Read only, will not be performed in lab.
  5. ABO/Rh Blood Typing: Understand blood typing.
  6. Complete Review Sheet: Pages 429-433, answer all questions EXCEPT: 9 and 19-22, instructor will review answers.

Composition of Blood

  • Average Volume:

    • Adult Males: 5-6 L
    • Adult Females: 4-5 L

  • Blood Type: Connective tissue composed of:

    • A. Plasma (~ 55% of blood, also called Unformed Element):
    • Composed of Nutrients, gases, hormones, wastes, proteins, electrolytes, etc. (contains 90% water).
    • Note: Serum is Plasma minus blood clotting factors.
    • B. Formed Elements (~ 45%):
    • Erythrocytes (RBCs)
    • Leukocytes (WBCs)
    • Platelets (important for clotting).

Overview of Blood as Connective Tissue

  • Components:
    • Cell nuclei observed in different connective tissues (e.g., Fibrous, Loose, Adipose).
    • Red and white blood cells illustrated as types of blood cells.

Figure 29-1: Composition of Blood

  • Plasma (55%):

    • Constituents and Functions:
    • Water: Solvent for carrying other substances; absorbs heat.
    • Salts (Electrolytes):
      • Sodium, Potassium, Calcium, Magnesium, Chloride, Bicarbonate.
    • Plasma Proteins:
      • Albumin: Osmotic balance.
      • Fibrinogen: Clotting of blood.
      • Globulins: Defense (antibodies) and lipid transport.
    • Substances transported by blood: Nutrients (glucose, fatty acids, amino acids, vitamins), waste products of metabolism (urea, uric acid), respiratory gases (O2 and CO2), hormones.

  • Formed Elements (45%):

    • Cell Types: Number of cells per mm³ of blood and Functions:
    • Erythrocytes (RBCs): 4-6 million, Function: Transport oxygen and help transport carbon dioxide.
    • Leukocytes (WBCs): 4800-10,800, Function: Defense and immunity.
    • Platelets: 150,000-400,000, Function: Blood clotting.

Summary of Formed Elements of the Blood

Formed Elements (First part):

  • Erythrocytes:

    • Shape: Biconcave, anucleate disc, salmon-colored; diameter 7-8 µm.
    • Development: 15 days; Life Span: 100-120 days.
    • Function: Transport oxygen and carbon dioxide.

  • Leukocytes:

    • Spherical, nucleated cells; 4800-10,800 per µl.
    • Types of Granulocytes:
    • Neutrophil:
      • Nucleus: multilobed
      • Function: Phagocytize bacteria.
    • Eosinophil:
      • Nucleus: bilobed.
      • Function: Kill parasitic worms; complex role in allergy and asthma.
    • Basophil:
      • Nucleus: lobed; Function: Release histamine and mediators of inflammation; contains heparin (anticoagulant).

Summary of Formed Elements (Second part):

  • Agranulocytes:
    • Lymphocyte:
    • Shape: Spherical/indented nucleus; function: Mount immune response by direct cell attack or via antibodies.
    • Monocyte:
    • Shape: U or kidney-shaped nucleus; function: Phagocytosis; develop into macrophages in tissues.
  • Platelets:
    • Function: Seal small tears in blood vessels; instrumental in blood clotting.

Blood Pathologies

  1. Polycythemia: Abnormal excess of RBCs, increases blood viscosity causing sluggish blood flow.
  2. Anemia: Blood has abnormally low O2-carrying capacity due to too few RBCs or too low hemoglobin.
  3. Leukocytosis: WBC count over 11,000 per ml, increase is a normal response to infection.
  4. Leukopenia: Abnormally low WBC count.

Blood Smear Exercise (page 419)

Procedure Overview: