Non-Specific Resistance Against Disease Flashcards
nonspecific resistance is
innate, or built-in protection against invasion by a wide range of pathogens
pathogens are
disease-producing agents that include infectious organisms, toxic chemicals, radiation
human body harbors billions of bacteria because
homeostasis provides ideal temp, moisture, pH and nutrients for microbial life
the first line of defense against pathogens are
the skin and mucous membranes
skin is typically too
dry and nutrient poor for microbes to survive
epidermal cells and keratin provide
mechanical barrier against microbes
coat of antimicrobial chemicals and lactic acid from sweat cover
skin and protect from pathogens
sebaceous glands secrete
oily sebum to form protective film over skin
mucous membranes line
body cavities that are open to the exterior and secrete mucous to trap microbes that try to enter these cavities
areolar connective tissues contains
hyaluronic acid which gives it thick and sticky consistency that makes it difficult for microbes to penetrate
the lacrimal apparatus secretes
tears to keep microbes from infecting the eyeballs
saliva dilutes
the number of microorganisms and washes them from the teeth and mouth
sweat glands produce
perspiration to flush microorganisms from the skin
mucus, tears, saliva, and perspiration contain
lysozyme which dissolves bacterial walls
urine prevents
microbial growth in the urinary system by constantly flushing the urethra
acidic secretions from gastric glands in the stomach and glands in the vagina retard
bacterial growth in the intestinal tract and female reproductive tract, respectively
organisms that get past the skin and mucous membranes are
attacked by phagocytes
phagocyte adheres to a pathogen by
recognizing its carbohydrate signature
neutrophils usually
phagocytize bacteria, but they can also kill bacteria with chemicals
neutrophil releases enzymes to form
a “killing zone” around itself which kills many more bacteria than it could destroy by phagocytosis
killing zone typically contains
hydrogen peroxide and hypchorite to kill bacteria but neutrophil also dies
-may contribute to the development of rheumatoid arthritis
natural killer (NK) cells are
large lymphocytes produced in red bone marrow, which kill a wide variety of bacteria and host cells that have become cancerous or gotten infected with viruses
when a natural killer cell encounters a microbe or an abnormal host cell,
it secretes perforins to rupture membrane and destroy target cell
natural kills cells are found in
blood, the spleen, lymph nodes, and red bone marrow