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Functions of the Immune System  To protect the entire body from a variety of harmful substances  pathogenic microorganisms  allergens  toxins  malignant.

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Presentation on theme: "Functions of the Immune System  To protect the entire body from a variety of harmful substances  pathogenic microorganisms  allergens  toxins  malignant."— Presentation transcript:


2 Functions of the Immune System  To protect the entire body from a variety of harmful substances  pathogenic microorganisms  allergens  toxins  malignant cells

3 Antigen-Antibody Reactions  Antigen - any substance that the body regards as foreign (virus, bacterium, toxin)  Antibody - a disease fighting protein developed by the body in response to the presence of an antigen

4 Structures of the Immune System  Not contained in a single system  Action depends on structures from lymphatic, cardiovascular, and Integumentary systems  Works primarily through antigen-antibody reaction

5 Check for Understanding 1.What other body systems work with the immune system? How do they work together? Hint* Think back to the past units. 2.What are all the different vocabulary words that mean viruses, bacteria and fungus?

6 External Defenses  Intact skin and mucous membranes  Form physical barriers that stop the entry of pathogens  Certain cells of the mucous membranes produce mucus  A viscous fluid that traps microbes and other particles

7 Body’s Defenses  In the trachea, ciliated epithelial cells  Sweep mucus and any entrapped microbes upward, preventing the microbes from entering the lungs Figure 43.3 10  m

8 Secretions of the skin and mucous membranesSecretions of the skin and mucous membranes Provide an environment that is often hostile to microbesProvide an environment that is often hostile to microbes Secretions from the skinSecretions from the skin Give the skin a pH between 3 and 5, which is acidic enough to prevent colonization of many microbesGive the skin a pH between 3 and 5, which is acidic enough to prevent colonization of many microbes Also include lysosymes, that digests the cell walls of many bacteriaAlso include lysosymes, that digests the cell walls of many bacteria

9 Check for Understanding 1.What is the trachea? Where is it located? 2.What is an epithelial cell? 3. What is a lysosome? Where is it found? Why would skin cells need them more? Hint* Think back to the cell unit. 4.If your body is fighting a war against pathogens, why is it smart to put defenses where it did? Where are they placed? Why is that strategic?

10 Immunity Immunity- state of being resistant or not susceptible to a specific disease

11 Natural  At birth, inherited and permanent.  Includes: Unbroken skin Mucus and tears Blood phagocytes Local inflammation Acquired   Body’s reaction to invaders   Passive Acquired   Active Acquired

12 Acquired Immunity  Passive Acquired  Injecting antibodies (not patients) to fight a disease  Mother to newborn  Active Acquired  Natural types are people recovering from a disease and can’t get it again  Artificial types are vaccines

13 Check for Understanding 1.What is the difference between injecting antibodies and injecting a vaccine? How does your body respond differently?

14 WBCs for Immune Reactions  Monocytes - formed in bone marrow/transported where needed by body  become macrophages  Macrophage - phagocytic cell that protects body by ingesting invading cells  Lymphocytes - major class of WBCs  formed in lymphatic tissue Figure 43.1 3m3m3m3m

15 Where Immune Cells come from


17 Macrophage Large numbers are released during infections Large numbers are released during infections Short lived – die after digesting bacteria Short lived – die after digesting bacteria Found in the organs, not the blood. Made in bone marrow as monocytes, called macrophages once they reach organs. Initiate immune responses as they display antigens from the pathogens to the lymphocytes.

18 Phagocytosis Process of engulfing and destroying cells.

19 Lymphocytes  T cells or T Lymphocytes  mature in thymus gland  Cell mediated immunity  B cells or B Lymphocytes  mature in bone marrow  antibody-mediated immunity

20 Check for Understanding 1.What is the relationship between monocytes and macrophages? 2.What is the relationship between Lymphocytes, B-Cells and T-Cells? 3.Where are macrophages found? 4.Where are B-Cells found? 5.Where are T-Cells found?

21 T Cell or T Lymphocyte  T Cell (cell mediated immunity)  Helper T-cells  The Helper T-cells coordinate the attack.  Killer T-cells  Killer T-cells do the work of destroying the infected cells.

22 B-Cells There are 10 million different B- lymphocytes, each of which make a different antibody. PLASMA CELLSome activated B cells become PLASMA CELL. Plasma cells produce antibodies ~1000/sec

23 Antibodies Antibodies don’t attack viruses. Antibodies attach to viruses, and bring them in clumps to macrophage.


25 B-Cells Other Roles  Some activated B cells  MEMORY CELLS.  Memory cells divide rapidly as soon as the antigen is reintroduced.  When the pathogen/infection infects again it is destroyed before any symptoms show.

26 Check for Understanding 1.What is the relationship between antibodies and macrophages? 2.Where do antibodies come from? 3.How many T-Cells are there and what are their individual jobs? 4.Why are B-Cells so special that they are called “morphing” cells?

27  Major events in the local inflammatory response Figure 43.6 Pathogen Pin Macrophage Chemical signals Capillary Phagocytic cells Red blood cell Bloodclottingelements Blood clot Phagocytosis Fluid, antimicrobial proteins, and clotting elements move from the blood to the site. Clotting begins. 2 Chemical signals released by activated macrophages and mast cells at the injury site cause nearby capillaries to widen and become more permeable. 1 Chemokines released by various kinds of cells attract more phagocytic cells from the blood to the injury site. 3 Neutrophils and macrophages phagocytose pathogens and cell debris at the site, and the tissue heals. tissue heals. 4


29 Function of Lymphatic System Returns excess interstitial fluid (from tissues) to circulatory system Absorption of fat and fat soluble vitamins from GI system Defense against invading pathogens and disease

30 Lymphatic System  Major structures  lymph vessels  lymph nodes  lymph fluid  Tonsils  Lymphatic trunks  Collecting ducts  Also  spleen  thymus

31 Lymph System  Fluid in lymphatic capillaries are called “lymph”  Lymphatic vessels are like blood veins with valves  Lymph nodes are specialized organs




35 Lymph Nodes  located in lymph vessels  small round or oval structures (filters)  depositories for cellular debris  bacteria and debris phagocytized  Swollen if bacteria is overwhelming



38 Check for Understanding 1.Glue the lymph model in your notebook and label all major lymph nodes and clusters. 2.Why are lymph nodes so important? 3.Why are lymph vessels and the cardiovascular system so closely connected?

39 Spleen  Sac-like mass of lymphatic tissue  filter for blood from lymph  Phagocytic cells (macrophages) used to destroy bacteria and toxins

40 Thymus  Primary role: matures T cells  T cell development: cells migrate from bone marrow and differentiate into T cells  Thymus gets progressively smaller (and less active) through life

41 Tonsils  Used to catch pathogens before they are swallowed into the GI tract.  any or all may become so loaded with bacteria that the pathogens gain dominance. Should not be removed unless absolutely necessary


43 Lymph  Carry proteins back into blood  Absorb dietary fats  Transport pathogens to lymph nodes to be destroyed  Maintain balance of pressure in tissue fluid

44 Exercise is important Lymphatic vessels are not muscles Need physical exercise to contract and push lymph through vessels Squeezing vessels cause flow to go into collecting ducts


46 Check for Understanding 1.Why do elderly people get sick more often than young adults? Give specific examples and reference specific organs. 2.What immune cells are found in the bone marrow? Hint* Look through all your notes. 3.What immune cells are found in the Thymus? 4.How are blood vessels and lymph vessels different? 5.Why do people say that exercise and health go together?

47 Acquired Immune Deficiency Syndrome (AIDS)  Caused by HIV (Human Immunodeficiency Virus)  HIV infects T-helper cells with often a long incubation of up to 10 years  AIDS name applied during advanced stages of disease  After immune system destroyed, opportunistic infections occur.

48 Autoimmune Disorders Antigens stimulate development of antibodies that are unable to distinguish antigens of internal cells. Body makes antibodies and T cells against itself and attacks own tissues. Multisystemic involvement. Myasthenia gravis, rheumatoid arthritis

49 Edema  Hypoproteinemia  lowers osmotic pressure within blood  large amounts of plasma pass out of blood  poor lymph drainage  increased capillary permeability  congestive heart failure  localized edema, ascites

50 Hemophilia  Hereditary blood clotting disorder  sex-linked, usually in men  lack factor VIII, essential for blood clotting  hematomas  hemarthrosis

51 Infectious Mononucleosis  Acute infection caused by virus.  Fever, sore throat, swollen lymph glands, atypical lymphocytes, splenomegaly, hepatomegaly, abnormal liver function, and bruising.  transmitted by droplet infection  Infection confers permanent immunity  Treatment symptomatic

52 Oncology, the study of tumors  Metastasis, Metastasize  Carcinoma  Malignant Melanoma  Adenocarcinoma  Sarcoma (arises from bone, fat, muscle, etc.)  Osteocarcoma  Osteosarcoma  Myosarcoma  Myeloma

53 Leukemia  Major oncological disorder of blood-forming organs  Monocytes develop quickly in to B or T cells but do not die  Cancerous B or T cells overcrowd the body and organs until other cells can’t function normally

54 Hodgkin’s Disease  Malignant disorder- Cancer cells can spread  Cancerous B cells begin to form and grow abnormally large  Painless, progressive enlargement of lymph tissue  Anorexia, weight loss, anemia

55 Kaposi’s Sarcoma  Malignancy associated with AIDS  lesions emerge as purplish-brown macules and develop into plaques and nodules

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