Introduction to Blood and Immunity

Introduction to Blood

• Blood is a circulatory fluid transporting oxygen and nutrients, while removing waste products from tissues.
• It consists of 55% plasma (water, proteins, hormones) and 45% formed elements (red blood cells, white blood cells, and platelets).

Blood Cells

• Red blood cells (erythrocytes) carry oxygen and carbon dioxide.
• White blood cells (leukocytes) are responsible for immunity and defense against infection.
• Platelets (thrombocytes) play a key role in blood clotting (hemostasis).

Immunity

• Immunity is the body's defense against harmful microorganisms and foreign substances.
• Innate immunity is non-specific and includes inborn defense mechanisms like skin and mucus.
• Adaptive immunity is acquired defense specific to certain pathogens.

Components of Adaptive Immunity

• T cells provide cell-mediated immunity by directly attacking foreign invaders.
• B cells are responsible for humoral immunity by producing antibodies.

Medical Terminology related to Blood

• Hem/o, Hemat/o: Refer to blood.
• Erythr/o: Refers to red.
• Thromb/o: Refers to clot.
• Leuk/o: Refers to white.

Medical Terminology related to Blood & Immunity

• Hematocrit: The proportion of red blood cells in the blood.
• Hemostasis: The process of stopping bleeding, including blood clot formation.

Medical Terminology related to Immunity

• Immun/o: Refers to immunity or the immune system.
• Immunization: The process of inducing immunity.
• Immunoglobulin (Ig): Antibody proteins that protect against infections.
• Antigen: A substance that triggers an immune response.
• Antibody (Immunoglobulin): A protein produced by B cells that helps neutralize pathogens like bacteria and viruses.
• Neutropenia: A decrease in neutrophils, a type of white blood cell, making the body more vulnerable to infections.
• Eosinophil: A white blood cell type involved in allergic reactions and fighting parasitic infections.
• Lymphocyte: A white blood cell type involved in immune response.

Disorders Related to Blood

• Anemia: A deficiency of red blood cells or hemoglobin.
• Leukemia: Cancer involving overproduction of white blood cells.

Disorders Related to Immunity

• Autoimmune Diseases: The immune system attacks the body's own cells.
• Immunodeficiency Disorders: A weakened immune system, such as in HIV.

Medical Terminology Prefixes and Suffixes

• -phylaxis: Refers to protection or prevention.
• Lymph/o: Refers to lymph or the lymphatic system, part of the immune system.
• -globulin: Refers to proteins involved in immune response.
• Auto-: Prefix meaning "self."
• -cytosis: Refers to an abnormal increase in the number of cells.
• Hypersensitivity: An exaggerated immune response to a foreign substance.

Clinical Case: Iron Deficiency Anemia

• Patient: Jane Smith, 45 years old, office worker.
• Symptoms: Fatigue, shortness of breath on exertion, headaches, dizziness, especially when standing up quickly.
• Investigations: Hemoglobin: 9.0 g/dL (normal: 12-15 g/dL), Hematocrit: 28% (normal: 36-46%), Ferritin: 8 ng/mL (normal: 20-200 ng/mL), Low iron levels.
• Diagnosis: Iron deficiency anemia secondary to chronic blood loss from menorrhagia (heavy menstrual bleeding).
• Treatment: Ferrous sulfate 325 mg PO daily for 3 months.