the immune system chapter 43. overview innate vs. acquired immunity innate immunity: present from...
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The Immune SystemChapter 43
Overview Innate vs. Acquired Immunity
Innate Immunity:Present from the time of birthNonspecificExternal 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 pHPhysical barrier
Mucous membranesTraps microbes
Antimicobial Proteins - Lysozyme Enzyme that destroys bacteria
Internal Cellular & Chemical Defenses
PhagocytosisThe ingestion of invading microorganisms by certain
types of white blood cells4 white blood cells are phagocytic
Neutrophils Macrophages Eosinophils Dendritic cells
Phagocytosis
Lymphatic system
Internal Cellular & Chemical Defenses
Antimicrobial ProteinsAttack microbes LysozymeComplement 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 injuryHistamine 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 CellsPatrol the body and attack virus-infected body cells
and cancer cellsApoptosis – 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 lymphocytesB 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 antigenPeaks about 10-17 days after exposure
Secondary Immune response: occurs after a second exposure to the same antigenFasterGreater magnitudeMore 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 moleculesLupus – skin rashes, fever, arthritis, and kidney
dysfunctionRheumatoid arthritis – painful inflammation of
cartilage and bond of jointsMultiple 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 systemHormones 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)
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