zoom Ch.5 blood/plasma/platletes

Overview of Blood Composition

  • Blood is comprised of two main components:

    • Plasma: 55% of blood, a straw-colored fluid containing nutrients, hormones, and waste products.

    • Formed Elements: 45% of blood, consisting of various blood cells.

Formed Elements of Blood

  • Erythrocytes (Red Blood Cells):

    • Definition: Cells that are red in color ("erythro" means red, "cytes" means cell).

    • Main Function: Transport oxygen via hemoglobin, the oxygen-carrying protein found in these cells.

  • Leukocytes (White Blood Cells):

    • Definition: Cells that are white ("leuko" means white, "cytes" means cell).

    • Function: Defend the body against infectious organisms and foreign substances.

    • Types of Leukocytes:

      • Neutrophils:

        • Function: Kill pathogens through phagocytosis; attack bacteria, viruses, and fungi.

        • Formation: Created in red bone marrow.

      • Basophils:

        • Function: Cause allergic symptoms, releasing histamines that lead to allergic reactions.

        • Formation: Also formed in red bone marrow.

      • Eosinophils:

        • Function: Destroy parasitic organisms and play a role in allergic reactions.

        • Formation: Formed in red bone marrow.

      • Monocytes:

        • Function: Carry out phagocytosis; migrate from red bone marrow to various body tissues.

        • Formation: Formed in red bone marrow and lymphatic tissue.

      • Lymphocytes:

        • Function: Identify foreign substances and produce antibodies; involve B cells and T cells.

        • Formation: Created in both red bone marrow and lymph nodes/spleen.

  • Thrombocytes (Platelets):

    • Definition: Smallest formed elements in the blood.

    • Function: Play a vital role in blood clotting and stopping bleeding.

Plasma and Serum

  • Plasma:

    • Composition: 92% water; 8% consists of proteins including clotting proteins.

    • Clotting Proteins:

      • Fibrinogen: A protein involved in blood clotting.

      • Prothrombin: Another essential protein for clotting.

  • Serum:

    • Definition: Plasma with clotting proteins removed.

    • Note: Both serum and plasma are similar, but serum lacks clotting proteins.

Blood Types and Antigens

  • Blood Type Classification:

    • Based on the presence or absence of antigens on the surface of red blood cells.

    • Types include A, B, AB, and O; determined by presence of A or B antigens.

    • Rh Factor:

      • Defines presence/absence of Rh antigen on red blood cells (Rh positive or Rh negative).

      • Approximately 85% of Americans are Rh positive.

  • Important Terms:

    • Antigen: Any substance the body may react against, which can provoke an immune response.

    • Tolerogen: Foreign substances that do not elicit an immune response.

Examples of Antigens

  • Common antigens include:

    • Pollen

    • Bacteria

    • Viruses

    • Foods (e.g., peanuts)

    • Medications

    • Transplanted tissues

Blood Transfusions

  • Matching Rules:

    • Patients must not receive antigens their blood does not have to avoid serious or fatal immune reactions.

    • Specific combinations of blood types are required for safe transfusions (e.g., type A can receive A and O; type O can only receive O).

Conclusion

  • Understanding blood components, their functions, and blood type classifications is critical for health and medical applications, including blood transfusions.

  • Following diagnostic and treatment protocols is essential to avoid immunological complications during transfusions.