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White Blood Cells & Fluid Balance: From Dyscrasias to Homeostasis

White Blood Cells (WBCs): Blood Dyscrasias

  • Mature White Blood Cells: Separated into two main groups.

    • Granulocytes: Possess granules in their cytoplasm, which store enzymes released during infection to fight it.

    • Agranulocytes: Do not have granules in their cytoplasm.

  • Production and Location: Produced in the bone marrow and then migrate.

    • Found in the blood or the lymphatic system.

  • Main Function: To fight infection (whereas red blood cells carry oxygen).

  • White Blood Cell Count Significance:

    • High WBC Count: Indicates the body is fighting an infection.

    • Low WBC Count: Means the body is very susceptible to infection.

  • Terminology for WBC Alterations:

    • Leukocytosis: An increase in white blood cells.

    • Leukopenia: A decrease in white blood cells.

  • Diseases Related to Alterations in WBCs:

    • Infections: Can be viral, bacterial, or fungal.

    • Mononucleosis:

      • Contagious and viral infection.

      • Transmission: Kissing, coughing, sneezing.

    • Leukemia:

      • A bone cancer.

      • Occurs when the bone marrow produces too many abnormal cells.

    • Lymphomas: Two main types, with important distinctions to know:

      • Hodgkin's Lymphoma:

        • Relatively rare.

        • Highly treatable.

        • Impacts the lymphatic system.

        • Characterized by abnormal proliferation of B lymphocytes.

      • Non-Hodgkin's Lymphoma:

        • Malignant (cancerous).

        • Can metastasize (spread) throughout the body.

        • Not easily treatable.

        • Forms in the lymph system.

Fluid and Electrolyte Balance

  • Importance: Crucial for cellular function and maintaining homeostasis (the body's internal balance).

  • Key Electrolytes as Examples (Too much or too little can cause issues): Sodium, potassium, calcium, phosphorus, magnesium, carbon, hydrogen, and oxygen.

  • Water in the Body:

    • The human body is mostly made of water.

    • Approximately 60\% of body weight is water (this is the key number to remember).

    • Distribution (detailed percentage breakdown not required for memorization, but for understanding):

      • 40\% within the cells.

      • 14\% between the cells (interstitial fluid).

      • 5\% in plasma.

      • 1\% between the cells (this seems to be a slight redundancy for interstitial, likely an error in transcript or different specific minor compartment).

  • Factors Affecting Water Percentage:

    • Sex: Women typically have a lower percentage of body weight from water than men.

    • Age: The percentage of body weight from water decreases as individuals get older.

    • Obesity: Can also decrease the body weight percentage from water.

  • Processes Maintaining Water Balance:

    • Osmosis:

      • The movement of fluids across a semipermeable membrane.

      • Purpose: To maintain osmotic pressure, ensuring everything is