The Lymphatic and Immune Systems

1. The Lymphatic and Immune Systems Chapter 6

2. Overview • Lymph – lmyph/o • Lymphatic Vessels and Ducts – lymphangi/o • Lymph Nodes – lymphaden/o • Tonsils and Adenoids – tonsill/o, adenoid/o • Spleen – splen/o • Bone Marrow – myel/o • Lymphocytes – lymphocyt/o • Thymus – thym/o • Immune System – immun/o

3. Objectives • Identify the medical specialist who treat disorders of the lymphatic and immune systems • Describe the major functions and structures of the lymphatic and immune systems • Recognize, define, spell, and pronounce the major terms related to the pathology, diagnostic and treatment procedures of the lymphatic and immune systems • Recognize, define, spell and pronounce terms related to oncology

4. Introduction • The lymphatic and immune systems work hand in hand to protect and maintain the health of the body • Roles and functions can are performed by specialized or shared structures; additional roles are played by other body systems

5. Medical Specialties

6. Allergist – specializes in diagnosing and treating conditions of altered immunologic reactivity, such as allergic reactions • Immunologist – specializes in dx and tx disorders of the immune system • Oncologist – a physician who specializes in dx and tx malignant disorders such as tumors and cancer

7. Functions of the Lymphatic System

8. Performs 3 primary functions in cooperation with other body systems • Absorbing fats and fat-soluble vitamins from the small intestine • Removing waste from tissues • Providing aid to the immune system

9. Absorption of Fats and Fat-Soluble Vitamins • Food is digested in the small intestine and from here nutrients, fat, and fat-soluble vitamins are absorbed • Villi (small finger-like projections) contain blood vessels that absorb most of the nutrients from the digested food directly into the blood stream. • Fats and fat-soluble vitamins that cannot be absorbed are transported by the lymphatic system

10. Waste Removal from the Tissues • The lymphatic system removed waste products and excess fluids created by the cells • Also destroys pathogens and takes away foreign substances that are present in the tissues

11. Cooperating with the Immune System • Lymph nodes play an active role in cooperation with the immune system to protect the body against invading microorganisms and disease.

12. Structures of the Lymphatic System

13. Lymphatic Circulation • Lymphatic Circulation – transports lymph from tissues throughout the body and eventually returns the fluid to venous circulation • Lymph – clear, watery fluid that transports waste products and proteins out of the spaces between the cells of the body tissues; also destroys pathogens • Lymph vessels are closely aligned with those of the CVS, so it’s sometimes called the secondary circulatory system • Differences in the two systems: • Lymph flows in 1 direction; from point of origin to venous circulation in the region of the neck • Lymph stays in lymphatic circulation until it goes into venous blood flow • Lymphatic system doesn’t have a pumping mechanism to it • Lymph is clear • Lymph is filtered by lymph nodes, not the kidneys

14. Interstitial Fluid and Lymph Creation • Interstitial fluid – intercellular or tissue fluid; is plasma from arterial blood that flows out of the capillaries and into the spaces between the cells; transports food, oxygen and hormones to cells • About 90% of this fluid is reabsorbed, the 10% that is not becomes lymph

15. Interstitial Fluid and Lymph Creation • Lymphatic Capillaries • Microscopic, blind-ended tubes located near the surface of the body; one cell in thickness allowing lymph to enter the capillary • Lymphatic Vessels and Ducts • Lymph flows from lymphatic capillaries to larger lymphatic vessels • Right Lymphatic Duct – collects lymph from the R side of the head and neck, the upper R quad and the R arm. Empties into the R subclavian vein • Thoracic Duct – the largest lymphatic vessel; collects from the L side of the face and neck, upper L quad, L arm and the entire lower trunk and both legs. Empties into the L subclavian vein

16. Interstitial Fluid and Lymph Creation • Lymph Nodes • Small, bean-shaped nodes that are specialized lymphocytes that are capable of destroying pathogens • There are between 400 and 700 lymph nodes located along the larder lymphatic vessels; appox ½ are in the abdomen • Cervical Lymph Nodes – located along side the neck • Axillary Lymph Nodes – located under the arms in the area known as the armpits • Inguinal Lymph Nodes – located in the inguinal (groin) area of the lower abdomen

19. Additional Structures of the Lymphatic System • Lymphoid – pertaining to the lymphatic system • The Tonsils– three masses of lymphoid tissue that form a protective ring around the back of the nose and upper throat • Adenoids – nasopharyngeal tonsils; located in the nasopharynx • Palatine Tonsils – located on the L and R sides of the throat in the area that is visible through the mouth • Lingual Tonsils – located at the base of the tongue

21. Additional Structures of the Lymphatic System • The Thymus– located superior to the heart; made up of lymphoid tissue, it’s an endocrine gland that assists the immune system • Peyer’s Patches and the Vermiform Appendix – work with the immune system to protect against the entry of pathogens • Peyer’s Patches are located in the ileum (sm intestine) • Vermiform Appendix hangs from the lower portion of the cecum (lg intestine)

24. Additional Structures of the Lymphatic System • The Spleen – a sac-like mass of lymphoid tissue located in the L upper quad, inf to the diaphragm and post to the stomach • Filters microorganisms from the blood • Forms lymphocytes and monocytes (specialized WBCs) • Hemolytic – destroys worn-out RBCs; releases the hemoglobin for reuse • Stores extra RBCs; maintains balance between RBCs and plasma

26. Pathology and Diagnostic Procedures of the Lymphatic System • Lymphadenitis – swollen glands; inflammation of the lymph nodes • Lymphadenopathy – any disease process affecting a lymph node or nodes • Lymphangioma – a benign tumor found by an abnormal collection of lymphatic vessels due to a congenital malformation of the lymphatic system

27. Pathology and Diagnostic Procedures of the Lymphatic System • Splenomegaly – an abnormal enlargement of the spleen • Splenorrhagia – bleeding from the spleen • Lymphoscintigraphy – diagnostic test that is performed to detect damage or malformations of the lymphatic vessels

28. Pathology and Diagnostic Procedures of the Lymphatic System • Lymphedema – swelling due to an abnormal accumulation of lymph fluid within the tissues • Primary Lymphedema– a hereditary disorder due to malformation of the lymphatic system. • Secondary Lymphedema– caused by damage to the lymphatic system that most commonly produces swelling in the limb nearest to the damaged vessels

31. Functions and Structures of the Immune System

32. Functions of the Immune System • The primary function of the immune system is to maintain good health and to protect the body from harmful substances including: • Pathogens – disease-producing microorganisms • Allergens – substances that produce allergic reactions • Toxins – poisonous or harmful substances • Malignant Cells– potentially life-threatening cancer cells • Structures of the Immune System • Unlike other body systems, the immune system is not contained within a singe set of organs or vessels. Its function depends on structures from several other body systems

33. The First Lines of Defense • Intact Skin – wraps the body in a physical barrier that prevents invading organisms from entering • Respiratory System – traps breathed in matter with nose hairs and the moist mucous membrane lining or the resp system. The tonsils forma protective ring around the throat, and coughing and sneezing help expel the matter that gets through • Digestive System – acids and enzymes produced by the stomach destroy invaders • Lymphatic System – their structures and specialized WBCs work together to attack and destroy pathogens

34. The Antigen-Antibody Reaction • The immune reaction; involves binding antigens to antibodies • The reaction labels potentially dangerous antigens so they can be recognized and destroyed • Antigen – any substance the body regards as foreign • Viruses, bacteria, toxins, transplanted tissue, etc. • Allergen – a substance that produces an allergic reaction • Antibody – a disease-fighting protein created by the immune system in response to the presence of a specific antigen; created specifically to destroy and specific antigen

35. The Antigen-Antibody Reaction • Immunoglobulins - bind with specific antigens. • Produced by plasma cells (specialized WBCs that produce antibodies coded to destroy specific antigens) • 5 Types • Immunoglobulin G – most abundant; fight bacteria, fungi, viruses and foreign particles • Immunoglobulin A – fight ingested antigens; found in saliva, sweat or tears and prevent antigens from attaching to the epithelial surfaces that line organs • Immunoglobulin M – found in circulating body fluids; 1st responders • Immunoglobulin E – produced in the lungs, skin and mucous membranes; responsible for allergic reactions • Immunoglobulin D – found on the surface of B cells

37. Specialized Cells of the Antigen-Antibody Reaction • Lymphocytes – WBCs that are formed in bone marrow as stem cells • Mature and differentiate into lymphoid tissues throughout the body • B cells – B lymphocytes; specialized lymphocytes that produce and secrete antibodies • Most effective against viruses and bacteria circulating in the blood • When a B cell meets an antigen it is to destroy, to transforms into aplasma B cell, capable of producing a secreting antibodies that are coded to destroy specific antigens

40. Specialized Cells of the Antigen-Antibody Reaction • Dendritic Cells – specialized WBCs that patrol the body searching for antigens that produce infection • Grab, swallow and internally break apart the antigen • Project off, like tentacles, the broken antigen to alert and activate the T cells to protect against that antigen

41. Specialized Cells of the Antigen-Antibody Reaction • T cells – T lymphocytes; small lymphocytes that mature in the thymus • Kill infected cells on contact • Interferon – a family of proteins who fight viruses by slowing or stopping their multiplication • Lymphokines – direct the antigen-antibody response by signaling between the cells of the immune system; they attract macrophages to the infection site • Macrophage – the WBCs responsible for surrounding and killing invading cells • Phagocyte – the large WBCs that destroy substnaces like debris, dust, pollen and pathogens by phagocytosis; surrounding and swallowing them!

44. Specialized Cells of the Antigen-Antibody Reaction • Compliment • A group of proteins that normally circulate in the blood in an inactive form • Foreign cells, bacteria and antigens activate it • It marks the invaders and attracts phagocytes to destroy them

45. Immunity • The state of being resistant to a specific disease • Natural Immunity– passed from mother to fetus before birth • Passive Immunity– passed from mother to child after birth through breast milk • Acquired Immunity – Active Immunity; the production of antibodies by contracting an infectious disease or by vaccination against a disease (chicken pox vs HBV) • Vaccination – immunization; provides protection for susceptible individuals from communicable diseases • Done via vaccines – a prep containing an antigen; either whole or part of the dead or weakened antigen

46. Pathology and Diagnostic Procedures of the Immune System • A person’s immunity depends on 3 things: • General health – poor health = compromised immune system • Age – older individuals have more acquired immunity, but their immune systems tend to respond less quickly and effectively. Babies don’t have much acquired immunity. • Heredity – genes and genetic disorders may affect the functioning of one’s immune system

47. Pathology and Diagnostic Procedures of the Immune System • Allergic Reactions • Occur when the body’s immune system reacts to a harmless allergen as if it were a dangerous invader • Allergy – hypersensitivity; an overreaction to a particular antigen • Localized Allergic Response – cellular response; redness, itching and burning at contact site (think poison ivy) • Systemic Reaction – Anaphylaxis; anaphylactic shock; a severe response to an allergen. • Symptoms develop quickly and without medication, the patient can die within minutes

49. Pathology and Diagnostic Procedures of the Immune System • Allergic Reactions(cont’d) • Scratch Test – a dx text to ID common allergens • Antihistamine – medications to relieve or prevent the symptoms of hay fever, the common allergy to wind borne pollens, and other types of allergies • work by preventing the effects of histamine, the substance that causes itching, sneezing, runny nose and watery eyes