unit 4

• Chemotaxis: phagocytes are recruited to site of infection by cytokines.
• Recognition and Attachment: phagocytes bind microbe directly via MBLs or indirectly via opsonins.
• Engulfment: phagocyte sends out pseudopods to surround and engulf the material creating a phagosome.
• Phagolysosome formation: TLRs detect phagosome contents before it fuses with lysosomes.
• Destruction and digestion: lysosome components (enzymes) degrade the invader as pH decreases.
• Exocytosis: phagolysosome fuses with cytoplasmic membrane to release debris.
• If invading microbes are not cleared immediately, macrophages may produce cytokines to recruit more phagocytes.
• Phagocytosis is a bridge between innate and adaptive defense bc it eliminates pathogens and presents antigens to lymphocytes.
• Incubation period: no signs or symptoms of infection or illness.
• Prodromal phase: vague symptoms of illness or infection.
• Invasive phase: Most severe signs and symptoms of the disease occur during this phase.
• Acme: All signs and symptoms are at peak intensity.
• Decline phase: declining signs and symptoms of the disease, but the patient is still able to function.
• convalescence period: the patient is completely healthy, all well no more symptoms of infection or illness.
• Innate response: non specific alarm system to pathogens, damaged or stressed cells. First responders, called acute inflammatory response. Dissipates in 2 to 14 days.
• Adaptive response: Targeted response, antibodies are released and memory b cells are floating around with the information to take less time to recover if same pathogen comes back later.
• Macrophage identify invaders and attack. They also give off cytokines to call up reinforcements like neutrophils and natural killer cells.
• Epithelia: covers surfaces and cavities including digestive system and has tight junctions.
• Cilia: Lines the respiratory system, sweeps bacteria out of lungs into the stomach.
• Mucus: sticky trap for pathogens, prevents the spread of bacteria.
• Antimicrobial proteins: proteins that disrupt the membranes of bacteria. Found everywhere, skins, saliva, lungs, and mucus.
• Microbiome: physical protection and antimicrobial proteins. Training of immune responses.
• Hair: protects from cuts, sensory, alerts of insects.
• Gastric juice: low pH in the stomach kills microbes in food.
• Monocyte: precursor to macrophages and dendritic cells. It lives in the blood and that moves into tissues.
• Neutrophil: first responder to inflammation; phagocytosis of bacteria; extracellular killing. It lives in the blood, moves into tissues.
• Basophil: involved in allergies/asthma. It lives in the blood, moves into tissues.
• Mast cell: Releases pro-inflammatory cytokines to start inflammation. It lives in tissues close to blood vessels, does not move.
• Eosinophil: A type of white blood cell that is involved in allergic reactions. Lives in tissue (upper resp, intestinal, other tissues) and can move.
• Dendritic cell: Monitor env; phagocytizes, bridge to adaptive immune response (first to present antigen) lives in tissue and can move.
• Macrophage: Phagocytosis of pathogens, debris, cells; can also present antigen. Lives in tissue, and can move.
• NK cells: Destroy virus infected and cancer cells. Lives in tissues (lymph nodes and other tissues) and can move.
• NK cells: triggers a cascade of protein activation that leads to apoptosis, is regulated but does not need activation.
• NK cells release perforin and granzymes to induce apoptosis.
• Neutrophils capture pathogens by netting. The nucleus breaks down and the protein net exits the neutrophil and captures microbes. (Pus)
• Dendritic cells break down pathogens and present pieces of the pathogen on their cell surface. The presentation of foreign pieces act like an alarm signal guiding other cells of the immune system to the infection.
• Fever: systemic increase in temperature-compared to inflammation local rise in temp.
• Hypothalamus regulates temperature. Pyrogens are substances that signal to increase set-point temp.
• Benefits of fever: increases temp for microbes, metabolism, phagocytosis, liver absorption, and lysosomal activity.
• Inflammation: tissue damage response (infection, injury, burns, allergies)