Chapter 43 Power Point notes

The Immune System Chapter 43

Overview Innate vs. Acquired Immunity  Innate Immunity:  Present from the time of birth  Nonspecific  External barriers, Mucous membranes, macrophages

 Acquired Immunity:  Highly specific  Humoral response (antibodies)  Cell-mediated response (cytotoxic lymphocytes)

Innate vs. Acquired Immunity

43 ~1 Innate Immunity External Defenses:  Skin  Acidic pH  Physical barrier

 Mucous membranes  Traps microbes

 Antimicobial Proteins - Lysozyme  Enzyme that destroys bacteria

Internal Cellular & Chemical Defenses  Phagocytosis  The ingestion of invading microorganisms by certain types of white blood cells  4 white blood cells are phagocytic  Neutrophils  Macrophages  Eosinophils  Dendritic cells

Phagocytosis

Lymphatic system

Internal Cellular & Chemical Defenses  Antimicrobial Proteins  Attack microbes  Lysozyme  Complement system – 30 proteins that activate when microbes invade  Interferon – protection against viral infection by limiting cell to cell reproduction

Internal Cellular & Chemical Defenses  Inflammatory Response – damage to tissue by physical injury  Histamine causes increased blood flow to the inured site (redness & heat = inflammation)  Help deliver antimicrobial proteins and clotting elements to the injured site

Inflammatory Response

Internal Cellular & Chemical Defenses  Natural Killer Cells  Patrol the body and attack virus-infected body cells and cancer cells  Apoptosis – NK cells release chemicals that lead to death of the cell by apoptosis (programmed cell death)

43 ~ 2 Acquired Immunity  Activates Lymphocytes  Antigen – any foreign molecule that is specifically recognized by lymphocytes and elicits a response from them  2 main types of lymphocytes  B lymphocytes (B cells)  T lymphocytes (T cells)  Both circulate through the blood and lymph and are concentrated in the spleen, lymph nodes, and other lymphoid tissue

Lymphocyte development  Originate from pluripotent stem cells in the bone marrow  T cells develop in the Thymus

 B cells remain in bone marrow and complete maturation there

Lymphocyte development

Primary vs. Secondary Immune response  Primary immune response: occurs the first time the body is exposed to a particular antigen  Peaks about 10-17 days after exposure

 Secondary Immune response: occurs after a second exposure to the same antigen  Faster  Greater magnitude  More prolonged

Primary vs. Secondary Immune response

43.3 ~ Humoral & Cell-mediated response  Humoral immune response – involves the activation and clonal selection of B cells, resulting in production of secreted antibodies that circulate in the blood and lymph  Cell-mediated immune response – involves the activation and clonal selection of cytotoxic T cells which directly destroy certain target cells.

Humoral vs. cell-mediated immune response

43.4 ~ Distinguishing self from non-self  Blood groups and transfusions  Tissue and organ transplants

Blood groups & Transfusions  A, B, AB, and O blood groups  A red blood cells have A antigens on their surface and make antibodies against the B antigen.

 Transfusion reaction – chills, fever, shock and kidney malfunction  AB = universal recipient  O = universal donor  Rh negative mother carries a fetus that is Rh positive mother mounts a humoral response. Danger occurs in subsequent pregnancies with Rh positive fetus.

Tissue & Organ Transplants  A rejection reaction is mounted in most graft and transplant recipients because molecules are foreign.  No danger of rejection if the donor and recipient are identical twins or if tissue is grafted from another part of the same person’s body.

43.5 ~ Immune system Diseases  Allergies – are exaggerated (hypersensitive) responses to certain antigens called allergens  Typical allergy symptoms: sneezing, runny nose, tearing eyes, and smooth muscle contractions  Anaphylactic shock – acute allergic response leads to a whole-body life-threatening reactions. Responses to bee venom, penicillin, peanuts, fish

 Epinephrine (epipen) counteracts this allergic response

 Autoimmune Diseases: The immune system loses tolerance for self and turns against certain molecules  Lupus – skin rashes, fever, arthritis, and kidney dysfunction  Rheumatoid arthritis – painful inflammation of cartilage and bond of joints  Multiple Sclerosis – T cells enter CS and destroy myeline sheath

 Arise from some failure in immune system regulation

 Immunodeficiency Diseases: The inability of the immune system to protect the body from pathogens or cancer cells that it should normally  Inborn (SCID) vs. acquired (AIDS)

 Stress & the Immune System: Healthy immune function depends on both the endocrine system and nervous system  Hormones secreted by the adrenal glands during stress affect the # of white blood cells and can suppress the immune system

 Acquired Immunodeficiency Syndrome (AIDS): Highly susceptible to infections (Pneumonia, bronchitis)  Loss of helper T cells both humoral and cell-mediated are imparied  Results from infection by HIV (retrovirus)