Blood Cells & Blood Typing

Blood Cells & Blood Typing

  • Overview of blood components and their significance in anatomy and physiology.

Blood Composition

  • Blood is composed of:

    • Plasma: 55% of blood

      • Water: 92%

      • Plasma Proteins: 7%

      • Other Solutes: 1%

    • Formed Elements: 45%

      • Red Blood Cells (RBC): 37-54%

      • White Blood Cells (WBC): <.1%

      • Platelets: <.1%

Blood Cells

  • Classification of blood cells:

    • Leukocytes (White Blood Cells):

      • Granulocytes:

        • Neutrophils

        • Eosinophils

        • Basophils

      • Mononuclear Cells:

        • Lymphocytes (T cells, B cells, NK cells)

        • Monocytes

    • Platelets: involved in clotting

    • Red Blood Cells: transport oxygen

Characteristics of Different Cell Types

  • Mast Cell:

    • Function: Inflammation via histamines; recruitment of macrophages/neutrophils.

    • Location: Connective tissues, mucous membranes.

  • Macrophage:

    • Function: Phagocytosis of pathogens and cancer; stimulates immune responses.

    • Location: Migrates from blood to tissues.

  • Natural Killer (NK) Cell:

    • Function: Kills tumor and virus-infected cells.

    • Location: Circulates in blood, migrates to tissues.

  • Dendritic Cell:

    • Function: Presents antigens; triggers adaptive immunity.

    • Location: Present in skin, lung, digestive tract; migrates to lymph nodes upon activation.

  • Neutrophil:

    • Function: First responders to infection; phagocytic.

    • Characteristics: Releases toxins to kill bacteria, migrates from blood to tissues.

Progenitor Cells and Differentiation

  • Common Myeloid Progenitor: Leads to different blood cells like granulocytes and erythrocytes.

  • Common Lymphoid Progenitor: Leads to lymphocytes (T, B, NK cells).

Components of Blood

  • Whole Blood: 8% of body weight; consists of plasma and formed elements.

  • Plasma: 55% of blood volume, containing various proteins, electrolytes, gases, and nutrients.

  • Formed Elements:

    • RVBCs: 4.8 - 5.4 million per μL

    • WBCs: 5,000 - 10,000 per μL

    • Platelets: 150,000 - 400,000 per μL

Eosinophilia

  • Causes:

    • Neoplasia (like CML, Hodgkin's lymphoma)

    • Allergies (asthma, Churg-Strauss)

    • Parasite infections

Eosinophil Function

  • Eosinophils attack large parasites externally when phagocytosis is not possible.

  • They release perforin and lytic enzymes to damage parasites and modulate inflammation.

Hemoglobin

  • Composition:

    • Primary Structure: Consists of chains of amino acids that bind oxygen.

    • Types: Oxyhemoglobin (with oxygen) and Deoxyhemoglobin (without oxygen).

    • Function: Carries oxygen; abnormalities lead to conditions like Sickle Cell Anemia.

Blood Typing

  • Antigens and Antibodies:

    • Antigen: Substance triggering immune response.

    • Antibody: Protein that binds to antigens to initiate response.

  • Blood Types: Defined by presence of surface antigens (A, B, Rh).

  • Key Combinations:

    • Type A: A antigens, anti-B antibodies.

    • Type B: B antigens, anti-A antibodies.

    • Type AB: A and B antigens, no antibodies.

    • Type O: No antigens, both anti-A and anti-B antibodies.

  • Rh Factor: Positive if Rh antigen present, negative if absent.

Blood Type Reactions

  • Mixing blood types can cause agglutination (clumping) if antibodies bind to foreign antigens.

Summary

  • A thorough understanding of blood composition, cell types, and blood typing is crucial in health sciences for diagnostics, treatment, and blood transfusions.