Chapter 2 Immunity and the Lymphatic System

1. Chapter 2Immunity and the Lymphatic System

2. Immunity • Immunity: The ability of the body to defend itself against infectious agents, foreign cells and even abnormal body cells. • Specific immunity: Also known as acquired immunity, effective against particular identified foreign agents and develops in response to contact with that agent. • Autoimmunity: Occurs when individuals develop antibodies to their own tissues or self-antigens.

3. Orderly Function of the Immune System • Functional components of the immune system: • lymphoid tissue • Primary – thymus, bone marrow • secondary – tonsils, adenoids, spleen, Peyer patches, appendix • lymphocytes • antibodies • macrophages

4. Orderly Function of the Immune System(cont’d.) • Major functions of the immune system: • Protect the body against foreign organisms • Maintain homeostasis by eliminating damaged cells (phagocytosis) • Battles infection

5. Orderly Function of the Immune System(cont’d.) • Inappropriate responses of the immune system: • Hyperactive (allergic) – excessive response • Immunodeficient (e.g., AIDS) – inadequate response • Autoimmune (e.g., SLE) – misdirected response • Transplant rejection – attack to beneficial foreign tissues

6. Immunodeficiency Diseases (cont’d.) • Acquired Immunodeficiency Syndrome (AIDS) • Caused by human immunodeficiency virus (HIV) • Diagnosed by presence of HIV antibodies in the blood (common test: ELISA; confirmation: Western blot) • HIV attacks helper T lymphocytes • Reduces cell-mediated immunity • Attacks nervous system directly

7. Immunodeficiency Diseases(cont’d.) • HIV transmission is through direct contact with blood or semen of infected person • sexual contact • blood transfusions and other blood products • contaminated shared needles (IV drug use, etc.) • accidental needle sticks • to fetus via placenta or during birth process from infected mother

8. Immunodeficiency Diseases(cont’d.) Universal Precautions • Thorough and frequent hand washing. • Personal protective equipment worn as required by specific task (e.g. gloves, gown, goggles, mask). • Proper disposal of all sharps in designated biohazard containers. • No needle recap prior to disposal. • Caution in handling of laboratory specimens. • Proper containment and disinfection of blood and body fluid spills. • Use clean mouthpieces and resuscitation bags.

9. Autoimmune Diseases • Lymphocytes and antibodies are sensitized to develop against the body’s own organs or tissues. • May be triggered by disease, injury, metabolic changes, or mutation in immunologically competent cells. • May be caused by certain drugs or chemicals, trauma, or viral infection.

10. Autoimmune Diseases (cont’d.) Pernicious Anemia • Symptoms: weakness and tingling and numbness in extremities, altered vision, lightheadedness, tinnitus, palpitations, weight loss, digestive disturbances, sore tongue. • Signs: decreased red blood cell, white blood cell, and platelet counts; increased red blood cell mean volume; decreased hemoglobin levels; jaundice; optic nerve atrophy; decreased amount of gastric acid.

11. Autoimmune Diseases (cont’d.) Connective Tissue Diseases • Systemic lupus erythematosus • Scleroderma • Sjogren syndrome • Rheumatoid arthritis • Juvenile rheumatoid arthritis • Ankylosing spondylitis • Polymyositis

12. Autoimmune Diseases (cont’d.) Systemic Lupus Erythematosus (SLE) • Inflammation of skin, joints, nervous system, kidneys, lungs, and other organs. • Butterfly rash across face may be present. • Other rashes may appear on other exposed skin areas.

13. Butterfly face rash Alopecia Photosensitivity Raynaud’s phenomenon Thrombocytopenia Discoid skin lesion Nasopharyngeal ulceration Polyarthritis Pleuritis or pericarditis Protein or casts in the urine Hemolytic anemia False-positive serology Abnormal blood antibodies LE cells (leukocytes) present in lab testing Autoimmune Diseases (cont’d.) Systemic Lupus Erythematosus (SLE)

14. Autoimmune Diseases (cont’d.) • Rheumatoid arthritis (RA) • Chronic, inflammation and edema of the synovial membranes surrounding joints. • Destruction of cartilage and adjacent bone. • May produce weight loss, fever, and malaise. • Joint pain and stiffness, especially in morning. • Bilateral joint tenderness, edema, erythema, warmth.

15. Autoimmune Diseases (cont’d.) • Multiple sclerosis (MS) • Inflammatory disease of the central nervous system. • Demyelination of nerves occurs in the brain and spinal cord. • Signs and symptoms are primarily neurologic and related to areas of myelin destruction.

16. Autoimmune Diseases (cont’d.) Myasthenia gravis (MG) • Chronic progressive neuromuscular disorder. • Autoantibodies produced to acetylcholine receptor in muscle cells. • Ineffective nerve-muscle junction results in severe weakness, difficulty talking and swallowing, drooping eyelids and diplopia.

17. Autoimmune Diseases (cont’d.) • Vasculitis • Inflammation in the walls of blood vessels that may lead to necrosis, thrombus formation, and local infarct • Can be classified as small vessel or systemic; affecting medium and large arteries