Please enable JavaScript.
Coggle requires JavaScript to display documents.
The Immune and lymphatic systems (Innate defenses (Internal Defenses (NK…
The Immune and lymphatic systems
Innate defenses
Surface Barriers
Skin
: keratinized stratified simple squamous layer makes the skin water-proof and resistant to invasion from most microbes.
Normal flora of the skin prevents pathogens from thriving.
Cells of the skin secrete antimicrobial substances; sebum, lysozyme, defensins, and dermicidin.
Mucous Membranes
: line the openings of the body.
Produce mucin that when hydrated forms mucus and also release lysozyme, defensins, and immunoglobulin A.
Normal flora of the mucosal membranes suppress the growth of other potentially more virulent bacteria.
Internal Defenses
Phagocytes
: engulf debris and infectious agents.
Include: neutrophils, macrophages, dendritic cells, mast cells, and eosinophils.
Fever
: caused by pyrogens interacting with the hypothalamus.
Inhibits replication of bacteria and viruses, promotes interferon activity, increases activity of adaptive immunity, and accelerates tissue repair.
NK cells
: release several chemicals, including perforins and granzymes.
Perforins punch holes in the plasma membrane of the cell.
Granzymes move into cell and trigger apoptosis
Antimicrobial proteins
: interferon and complement
Interferons are a category of cytokines. An infected cell will secrete interferons, making other cells resistant to viral reproduction.
Complement are proteins from the liver that work with antibodies to mark foreign cells for destruction.
Inflammation
: an immediate, local, nonspecific event.
Cardinal signs include: redness, heat, swelling, and pain. Loss of function is attributed to more severe cases of inflammation.
The increased fluid pressure caused by inflammation helps drive more fluid into the lymphatic capillaries.
Lymphatic Structures
Primary and secondary
Primary: bone marrow and the thymus.
Red bone marrow creates lymphocytes, B lymphocytes mature here as well.
Thymus is where T-lymphocytes go to mature and be challenged.
Secondary: lymph nodes, spleen, tonsils, lymphatic nodules, and MALT.
House lymphocytes and other immune cells following their formation.
Spleen filters blood.
Lymph nodes filters lymph.
Immunity
Active
: direct encounter with a pathogen or foreign substance.
Naturally acquired active immunity: directly exposed to the antigen of an infectious agent. Scrape or cut.
Artificially acquired active immunity: when exposure is through vaccine.
Passive
: obtained from another individual or animal.
Naturally acquired passive immunity: transfer of antibodies from mother to baby or in mother's breast milk.
Artificially acquired passive immunity:
serum
containing antibodies against a specific antigen is transferred form one individual to another. Anti-toxins, anti-venom.
Adaptive Defenses
Humoral Immunity
B cells
B lymphocytes can interact with foreign antigens directly and become activated, becoming either plasma cells or memory B cells.
Plasma cells release antibodies that mark foreign antigens for destruction by other immune cells.
Memory B cells circulate the body and become activated when they encounter the same antigen as before.
Cellular Immunity
T cells
T lymphocytes are unable to recognize foreign antigens on their own. An APC needs to present the antigen on an MHC.
Two types of cell arise from activation: helper T cells and cytotoxic T cells.
Helper T cells organize the body's immune response.
Cytotoxic T cells secrete chemicals that are fatal to cells.