Exam 19 - Introduction to Blood

Introduction to Blood and Lymphatic Systems

• Anemia: A condition with reduced red blood cells, hemoglobin deficiency, or increased red blood cell destruction. Decreased oxygen-carrying capacity is a result.
• Disseminated Intravascular Coagulation (DIC): A serious complication of various conditions; excessive clotting and clot breakdown occur in response to injury or severe illness.
• Erythrocytosis: An abnormally high red blood cell count and increased production of granulocytes and platelets.
• Hemarthrosis: Bleeding into a joint space.
• Hemophilia A: A genetic disorder where a person lacks factor VIII, essential for blood clotting.
• Heterozygous: Having two different genes for a trait.
• Homozygous: Having two identical genes for a trait.
• Idiopathic: Unknown cause.
• Leukemia: A type of cancer affecting the bone marrow and lymph nodes where too many white blood cells accumulate.
• Leukopenia: A very low white blood cell count.
• Lymphangitis: Inflammation of lymphatic vessels, often due to bacterial infections.
• Lymphedema: Fluid buildup due to lymphatic system dysfunction.
• Multiple Myeloma: A bone marrow cancer.
• Pancytopenia: Deficiency of all types of blood cells (red, white, and platelets).

Overview of Hematologic and Lymphatic Systems

• The systems are key for maintaining homeostasis.
• Diseases affecting these systems can have wider body system implications.
• Blood: Transports oxygen, nutrients, and removes waste products.
• Lymphatic System: Filters harmful substances and maintains fluid balance.

Characteristics and Functions of Blood

• Blood is a viscous fluid containing red blood cells, white blood cells, platelets, and plasma.
• Plasma makes up 55% of blood; remaining cells are RBC, WBC, and platelets.
• Blood's pH is slightly alkaline (7.35-7.45).
• Average adult blood volume is 5-6 liters.
• Functions: Transports substances, regulates acid-base balance, controls temperature, defends against infection, and aids in blood clotting.

Red Blood Cells (Erythrocytes)

• Components: Contain cytoplasm and hemoglobin for oxygen transport.
• RBC characteristics: Can be normochromic, hypochromic, macrocytic, normocytic, or microcytic.
• Lifespan: Approximately 120 days.
• Normal values: 14-18 g/dL for men, 12-16 g/dL for women (Hemoglobin).
• Production: Erythrocytes are produced in red bone marrow, with decreased oxygen levels stimulating the process. This happens in vertebrae, ribs, sternum etc
• Hematocrit: Measures the volume percentage of red blood cells in whole blood.
• Anemia: Low Hemoglobin levels resulting in decreased oxygen transport; can cause fatigue, shortness of breath etc.

White Blood Cells (Leukocytes)

• General Characteristics: Contain nuclei, colorless, and have varying lifespans (days to years).
• Categorization: Granulocytes (neutrophils, basophils, and eosinophils) and agranulocytes (monocytes and lymphocytes).
• Functions: Crucial in immune response, defense, and eliminating foreign invaders.

Thrombocytes (Platelets)

• Production and function: Produced in red bone marrow, assisting in clotting formation.
• Lifespan: 5-9 days.
• Normal value: 150,000-400,000 per mm3 of blood.
• Hemostasis: The body's process to stop bleeding; involving vessel spasm, platelet plug formation, and clot formation.

Blood Types and Rh Factor

• Determined by antigens on the surface of red blood cells.
• ABO system: A, B, AB (universal recipient) and O (universal donor).
• Rh factor: Rh+ or Rh-. If absent, the person is Rh negative.

Lymphatic System

• Overview: Part of the cardiovascular system, maintains fluid balance, and absorption and transport of lipids.
• Lymph fluid: Similar in composition to plasma, flows through lymphatic vessels etc.
• Lymphatic vessels: Connect lymph nodes, collecting lymph fluid, and connected to the circulatory system.
• Lymphatic nodes (glands): Filter impurities, produce lymphocytes.
• Tonsils: Protect against invasion.
• Spleen: Filters blood, matures lymphocytes, and destroys damaged cells.
• Thymus: Develops immune system.

Diagnostic Tests

• Complete Blood Count (CBC): Assesses various blood elements like red and white blood cells, hematocrit, and hemoglobin level.
• Erythrocyte Indices: Measures characteristics of red blood cells like size and hemoglobin content
• Differential Count: Identifies various types and percentages of white blood cells
• Peripheral Smear: Examines size, shape, and structure of blood cells microscopically.
• Schilling Test: Diagnoses vitamin B12 deficiency.

Blood Transfusion Therapy

• Reasons for Transfusion: To replace blood volume, oxygen-carrying capacity, decrease bleeding, and increase coagulation.
• Types of Transfusion: Donor blood, autologous.
• Initiating a Blood Transfusion: Blood typing and cross-matching to prevent reactions, informed consent, IV access to ensure safety etc

Coordinated Care

• Care: Nurses play a role including patient's safety and monitoring vital signs, identifying possible transfusion reactions during transfusions etc.
• Transfusion reactions: Possible adverse reactions to blood transfusions, such as hemolytic reactions or circulatory overload. Immediate steps need to be taken in case of suspected reactions.

Additional topics covered in the text include:

• Pernicious anemia
• Reed-Sternberg cells
• Thrombocytopenia