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cutaneous

-stratum corneum/outer most layer: composted of compact epithelial cells and keratin, results in a thick later that is waterproof; few pathogens can penetrate thick stratum corneum -hair follicles and skin glands: other cutaneous barriers; sheds and flushes to remove microbes

Immunology

-study of internal body defenses that protect against infection; phagocytosis, inflammation, acquired immunity -functions 1.surveillance of organs, tissues, and other compartments by WBC that recognize self from nonself 2.recognition and differentiation of normal components of the body and foreign material such as pathogens 3.attack against and destruction of foreign invaders.

lymphatic system

-system of vessels and organs that function to: return fluid into circulation, act as a drain off system for inflammatory response, and protect against foreign pathogens -lymph: plasma like fluid made when blood components move out of blood vessels to extracellular space and diffuse to lymph capillaries; composed of water, dissolved salts and protein; moves around WBC and other materials -lymphatic capillaries: accompany blood capillaries; has thin layer of epithelial cells w loose junctions that allows extracellular fluid to collect into circulatory system -diff b/t blood and lymph system:1.purpose of lymph system is to return lymph to circulation then to blood from extremities to heart; 2. lymph is moved by muscle contractions, while blood is moved by heart pump system

compartments of surveillance

-the reticuloendothelial system (RES) -the spaces surrounding tissue cells that contain extracellular fluid (ECF), -the bloodstream -the lymphatic system -capillaries = help convey activities of diff fluid compartments -due to vessels and capillaries; any production of a lymphatic reaction can be transmitted directly into blood between RES and ECF and vice versa

blood

-whole blood: formed elements and plasma -serum: same as plasma but lacks clotting protein; used in immune testing and therapy -Plasma: composed of mostly water, proteins, immunochemicals, fibrionogen and clotting factors, hormones, nutrients, ions + electrons, dissolved gasses and urea

Basophils

2 lobed, stained blue, similar to mast cells, least amount of WBC in circulation, have chemical mediator to attract other WBC toward infected area mast cells: nonmotile elements bound to connective tissue, act as first line of defense against local invasion of pathogen: recruit other inflammatory cells, responsible for release of histamine and allergic stimulants

Chemokines

Chemical mediators (cytokines) that stimulate the movement and migration of white blood cells.

Associated lymphoid tissue

MALT/Mucous associated lymphoid tissue: lymphocytes and WBC on mucous membranes; allows for reaction if microbe passes thru portal of entry; example is tonsils and breasts w breast milk filled w antibodies SALT/skin associated lymphoid tissue GALT/gut associated lymphoid tissue:in GI tract, immune functions against intestinal pathogens, source of antibodies; inc appendix and peyer patch

Erythrocytes

RBC that transports oxygen and co2 to and from tissue; no nuclei, biconcave shape sac of hemoglobin, no immune function

Lymphocytes

-2nd most common WBC in blood, small spherical cells w dark round nucleus surrounded by cytoplasm, can mimic monocyte look -two functional types: B lymphocyte and T lymphocyte, transported by bloodstream and lymph and move freely in lymphoid organ and connective tissue -3rd line of defense -activated by antigens to attack them -B cell: humoral immunity, forms plasma cells that produce antibodies for protection -T cell: participate in cell-mediated immunity where cells kill pathogen

Hematopoiesis

-blood cell formation -production of blood cells that begins in yolk sac then continues in red bone marrow -pluripotential stem cells: undifferentiated cells that will proliferate and mature & differentiate into other cells. -red blood cells (RBCs), white blood cells (WBCs, or leukocytes), and platelets (thrombocytes) = primary line

fever

-body temperature is normally maintained by a control center in the hypothalamus -started when hypothalamic thermostat is set at a higher setting, causes signals in musculatures to increase heat production and vasocontriction to decrease heat loss -core temperature at around 37°C (98.6°F) -pyrogens: exogenous (coming from outside the body) or endogenous (originating internally) -chills: caused bc thermostat of body is hotter than blood temperature; body shiver to produce more heat and vasoconstriction occurs -beneficial by allowing immune responses to work stronger

BENEFITS OF EDEMA AND CHEMOTAXIS

-dilutes toxic substances: due to influx of exudate and neutrophils -neutrophils: important in destroying microbes; can accumulate and contribute to pus (pyogenic bacteria)

WBC

-divided into two groups: granulocytes and agranulocytes -neutrophils, eosinophils, and basophils = granulocytes -monocytes and lymphocytes = agranulocytes

Phagocytes

-main types: neutrophils, monocytes, macrophages, and dendritic cells > go to site of infection due to gradient stimulant product from pathogen and host tissue at site of injury -means cell eating; attacks foreign pathogens in diff ways -event involved: chemotaxis, ingestion, phagolysosome formation, destruction, and elimination -when encounter pathogen: when phagocyte encounters pathogen uses toll like receptor to detect PAMP and lets nucleus know to stimulate release of chemical mediators and intracellular phagocytic processes

late rxn of inflammation

-monocytes, lymphocytes, and macrophages attracted to longer lasting inflammation -macrophages: clean up debris -scar: may be caused by diff levels of repair and replacement w connective tissue

mucus membrane

-mucocutaneous membranes of the digestive, urinary, and respiratory tracts and of the eye -moist and permeable; production of liquids usually flush out microbes

chemical defenses

-nonspecific -sebaceous secretions, tears, saliva, dermacidin -tears and saliva: have lysozymes (enzyme that breaks CW of bacteria) and defensins (peptides produced by cells and tissues that damage cell membrane and cause lysis of bacteria and fungi) -Skin cells: produce defencidin defensin that kills bacteria -paneth cells: secrete defensins in intestine to kill or destroy infectious agents -The high concentrations of lactic acid and electrolytes in sweat and the skin's acidic pH and fatty acid content are also inhibitory to many microbes -semen: has antimicrobial chemical to kill microbes -vagina: lactobacillus in normal flora protects acidic environment

Monocytes

-one of the larges WBC, 3rd common in circulation, kidney bean shape nucleus, cytoplasm has digestive enzymes, discharged by bone marrow into bloodstream -macrophage: when monocyte leaves circulation; functions in specific and nonspecific phagocytic and killing; processing foreign molecule and presenting to lymphocyte; secrete bio active compounds that cause immune actions -dendritic cells: product of monocyte line, trap pathogens and ingest them- stimulates them to participate w lymphocytes

inflammation

-reaction to a traumatic event in tissue that attempts to restore homeostasis, a process that clears invading microbes and cellular debris left by immune rxn -rubor, calor, tumor, and dolor = signs and symptoms -chronic inflammation: can cause tissue damage

pathogen-associated molecular patterns (PAMPs)

-recognized by PRR and TLR that are indicators of red flags and signal WBC to do innate immunity; detection allows for early alert of invasion and can help control pathogen before it spread more -PRR and TLR detection of PAMPs is nonspecific and nor selective for a single microbe

chemical mediators

Small molecules that are released during inflammation and specific immune reactions that allow communication between the cells of the immune system and facilitate surveillance, recognition, and attack. inflammation mediators cause: fever, stimulate lymphocytes, prevent infection spread, and cause allergic symptoms

C-reactive protein

a pattern recognition receptor,PRR; early indicatory of inflammation; is a large protein synthesized in liver that circulates in the blood; released due to cytokines released by macrophages; serves as localized innate protection bc helps in binding and phagocytising pathogen

Eosinophils

biloyed, red stain, more abundant in bone marrow and spleen than in circulation, granuales have digestive enzymes, function to attack eukaryotic pathogens (worms) and involvement in inflammation & allergic rxn; one of the early cells that accumulate in sites of inflammation n allergic rxn

cytokines

chemicals produced by WBC and other tissue cells that regulate development, inflammation and immunity

Opsonization

coating antigen with antibody enhances phagocytosis

reticuloendothelial system

connective tissue network that functions to attack foreign pathogens associated w mononuclear phagocyte system

phagolysosome

digestive vesicle formed by the fusing of a lysosome with a phagosome

Neutrophil Extracellular Traps (NETs)

fibrous matrix from neutrophils that is used to prevent further spread of infection; released when neutrophils die -composition: DNA, enzymes, histones, and other cell contents

complement

form of PRR that work w phagocytosis and inflammation to destroy pathogens; usually nonspecific and innate but can play a role in acquired immune responses; 3 defensive features: MAC, opsonization, inflammatory cells and cytokine release

respiratory tract

highly developed defenses include nose hair, mucus + fluid, cilia + epithelium, sneezing and coughing

Host defenses

innate (nonspecific) and acquired (specific) -first line of defense: innate, nonspecific, blocks invasion @ portal of entry -second line of defense: internalized system of protective cells and fluids, inflammation, phagocytosis, acts @ local and systemic levels when first line of defense is penetrated; non specific -third line of defense: adaptive and acquired; memory cells will come into play for future infections -most defenses overlap:defenses do not work separately; overlap eachother; this allows targeting of invading microbes on different fronts -microbial and bacterial residents can act as barriers of pathogens

membrane attack complex (MAC)

kill pathogen directly, cascade effect

Neutrophils

lobed nuclei, function in phagocytosis, most abundant leukocyte, granular, lives for 2 days -bacterial infection = high neutrophil count in blood

pattern recognition receptors (PRRs)

molecules that reside on on the membrane of WBC in order to detect pathogens

Macrophages

monocytes that migrate out to tissues, have improved organelles and functions, wander thru reticuloendothelial system; some stay in organs for whole life time (histiocytes)

chemotactic factors

movement of blood cells in reaction to infection

Platelets

not whole cells, formed by megakaryocytes, function in blood clotting and releasing associated chemicals

exudate

plasma that escape from small vessels into the tissues; accumulation of the fluid gives rise to edema; also due to leaky capillaries stimulated by cytokines; may be clear, have RBC or pus -vasoactive substances: can cause endothelial cells in venule walls to separate and forms gaps where blood borne components exude into extracellular space

antigen

protein molecules that interlock w foreign cells or molecules and help in their destruction

Interferon

protein produced by WBC and tissue cells, used for viral infections, cancer cells and an immune suppressor; bind to cell surface and cause change in genetic expression -synthesized when a nucleus gets a signal that virus binds to receptor on host cell; main role is to inhibt viral replication; non virus specific -play a role as a regulatory cytokine that activate or instruct development of WBC

Secondary lymphoid organs

spleen and lymph nodes, circulatory based locations where encounters w microbes and immune responses occur -Lymph nodes: small organs located along lymph channels and large blood vessels in thoracic and abdominal cavities; many in armpit, groin and neck region specialized for filtering out materials in lymph -spleen: lymphoid organ that filters blood

Pyrogens

substances that cause fever -Exogenous pyrogens: products of infectious agents, endotoxins, injectable solutions -Endogenous pyrogens: liberated by WBC, part of immune response; 2 released by macrophage: interleukin-1 and tumor necrosis factor

chemotaxis

tendency for cells to migrate in response to a specific chemical stimulus released at a site of injury; WBC from diff compartments go to infection site and do immune functions

primary lymphoid organs

thymus and bone marrow, location for developing WBC, origin and maturation of lymphocytes that have specific immune function -thyums: located above heart active from birth to puberty

Diapedesis

way for WBC to leave vessel and go to extracellular space at infection site; WBC adhere to endothelial cells and sqeeze thru to extracellular space