Transcript Nonspecific Defenses

Nonspecific Defenses
Adriana Perta
Marisa Pawlowski
Paige Simko
Rachel Ragone
Jill Ross
Nonspecific Defenses
• Occur automatically because they are innate
• No memory is involved- no recognition that
this same intruder has been attacked before
• Barriers to entry, the inflammatory response,
phagocytes and natural killer cells, and
protective proteins are types of nonspecific
defenses
Immunity
• The body’s capability to remove
foreign substances and to kill
pathogens and cancer cells
• Involves both nonspecific defenses
and specific defenses
Barriers to Entry
• Include nonchemical barriers such as
the skin and the mucous membranes
lining the respiratory, digestive, and
urinary tracts; serve as mechanical
barriers to entry by pathogens
• Also include antimicrobial molecules
(ex: oil gland secretions contain
chemicals that weaken or kill certain
bacteria on the skin)
• The stomach has an acidic pH, which
inhibits the growth of or kills many types
of bacteria
Inflammatory Response
(refer to page 637 figure 35.3)
• When tissue is damaged by physical or chemical agents or by
pathogens, a series of events occur
• An inflamed area has four outward signs: redness, heat, swelling,
and pain
• These signs are due to capillary changes in the damaged area
• Histamine: a chemical signal, released by damaged tissue cells
and mast cells
• Mast cells: a type of white blood cell in tissues, cause capillaries
to dilate and become more permeable
• Some inflammatory responses trigger fever, the onset being
controlled by the brain
• The fever serves to inhibit the growth of some microorganisms,
promotes accelerated tissue repair, stimulates immune cells to
divide and increases the production of viral-fighting interferon
Chronic Inflammation
• One that persists for weeks or longer
• Often treated by administering anti-inflammatory agents,
such as aspirin, ibuprofen, or cortisone
• These medications act against the chemical signals,
such as histamines, that bring about an inflammation
• Chronic inflammation is thought to play a role in many
human illnesses
• May lead to heart attacks, may destroy nerve cells in the
brains of Alzheimer patients, can also be involved in the
development of diabetes in obese individuals
• Autoimmune diseases involve inflammation, but in these
cases specific immunity seems to be the leading cause
• A healthy diet, exercise, and good dental hygiene can
reduce the occurrence of inflammation and help keep us
well by reducing the occurrence of chronic inflammation
Macrophages and Cytokines
• Macrophages: in tissues, that devour many
pathogens and survive
• Have receptors that allow them to
recognize the presence of pathogens
• Release cytokines
• Cytokines: chemical signals that stimulate
other white cells such as neutrophils and
monocytes, that then mature into
macrophages
Natural Killer Cells
• Large, granular lymphocytes that kill
virus-infected cells and cancer cells by
cell-to-cell contact
• Produce cytokines that stimulate these
cells
• Congregate in the tonsils, lymph nodes,
and spleen
• Look for a self protein on the body’s cell
• Not specific; have no memory; and their
numbers do not increase after stimulation
occurs
Protective Proteins
(refer to page 638 figure 35.4)
• Complement: composed of a number of blood plasma
proteins
• “complement” certain immune responses
• Involved in the inflammatory response because certain
complement proteins can bind to mast cells and trigger
histamine release
• Some combine to form a membrane attack complex that
produces holes in the surface of bacteria and viruses
• Interferons: proteins produced by virus-infected cells as a
warning to noninfected cells in the area
• Binds to receptors of noninfected cells, causing them to
prepare for a possible attack
• Used as treatment in certain viral infections like
hepatitis C