Chapter 16 Flashcards
immunity
ability to ward off disease, aka RESISTANCE. Lack of immunity: susceptibility
innate immunity
specificity & memory
2 lines of defense
presented at birth, prior to encounter with disease-causing agents.
Nonspecific, does not involve specific recognition or memory.
Readily protects against all diseases.
Includes 2 lines of defense:
1st: physical barrier – skin, mucous membranes.
2nd: internal, composed of protective cells, cellular agents, and processes that inactivate the disease-causing agents (phagocytes, interferons, inflammation, fever)
adaptive immunity
line of defense
slower to response because it has to activate what?
3rd line of defense; specific and has memory.
Defenses elicited upon encounter with the disease-causing agent.
Slower to respond because it has to activate the T lymphocytes and the B lymphocytes.
describe role of physical factors in the first line of defense
skin
mucous membranes
flush
Skin - as a physical barrier, blocks entrance of microbes. Outer epidermis and underlying dermis. Dryness and shedding of skin, thickness, and abundance of keratin are protective barriers.
Mucous membranes: block entrance of microbes. Consists of epithelial layer and underlying connective tissue layer. Lines gastro, respiratory, and genitourinary tracts.
LAST: tears, saliva, urine, mucous, vag secretion help flush microbes away.
describe role of chemical factors in the first line of defense
low pH
lysozyme
sebum
low pH either destroys or inhibits growth of microbes.
Lysozyme (in perspiration, tears, saliva, nasal secretions, tissue fluids, urine) can break chemical bonds on peptidoglycan; more effective against gram (+) vs gram (-).
Sebum - functions as protectant.
describe role of normal microbiota in the first line of defense
prevent overgrowth of pathogens.
2nd line of defense
composed of cells (Phagocytes), antimicrobial chemicals (complement system, interfereon, iron-binding proteins, antimicrobial peptides, processes (inflammation, fever)
components of the 2nd line of defense
plasma, leukocytes (WBC)
plasma
involved in blood clotting, inflammation, transporting iron.
leukocytes
WBCs, 2 groups based on granules in cytoplasm–granulocytes and agranulocytes
granulocytes
NBE
have granules in cytoplasm. Includes neutrophils, basophils, eosinophils
neutrophils
numbers granules stain: nucleus shape \_\_\_cyte increase during what kind of infection
most numerous WBC. Granules stain pink, have multi-lobed nucleus, are phagocytes (able to leave blood), numbers increase during acute infection
basophils
granules stain:
have a _____ shaped nucleus
release:
involved in:
granules stain blue-purple, have a U or S shaped nucleus, release histamine, involved in inflammation and allergic response
eosinophils
granules stain: nucleus shape can they leave blood? (word) increase during what kind of infection involved in what kind of reaction
granules stain red or orange, have a bi-lobed nucleus; phagocytic; able to leave blood; number increases during parasitic worm infections; involved in allergic reactions
agranulocytes
MDL
no granules visible, includes monocytes, dendritic cells, and lymphocytes
monocytes
nucleus shape
mature to what
become what in tissues
increase during what kind of infection (ex)
kidney-shaped nucleus; mature to macrophages and become actively phagocytic in the tissues; numbers increase during chronic infections, such as tuberculosis
dendritic cells
derived from abundant in what locations functions are to (2) senses bridges
derived from monocytes,
abundant in the epidermidis of skin, mucous membranes, thymus, lymph nodes;
function is to destroy microbes by phagocytosis (nonspecific),
initiate adaptive immunity (specific)–
dendritic cells sense the signals from innate immunity and trigger T cell activation, sort of bridging innate immunity and adaptive immunity
lymphocytes
nucleus shape
includes TBN
have a spherical nucleus, includes T lymphocytes, B lymphocytes, and natural killer cells
T lymphocytes
cellular immunity
B lymphocytes
humoral immunity (produce antibodies)
natural killer cells (NK cells)
function in innate immunity–kill infected host cells and tumor cells, and release perforin (poke a hole in the plasma membrane, causing cytolysis) and granzymes (induces apoptosis (self destruction))
leukocytosis
total # of WBC increases during infections (meningitis, infectious mono, appendicitis, pneumococcal pneumonia, gonorrhea)
leukopenia
decrease in leukocyte count, may be caused by salmonellosis, brucellosis, some viral and rickettsial infections
differential WBC count
count the % of leukocytes (percentage of each white cell in total WBC); serve as an indicator of disease
phagocytosis
ingestion of a microorganism or other substance by a cell. 2nd line of defense.
phagocytes
cells that perform phagocytosis, all are WBCs or derived from WBCs.
steps in phagocytosis
C
A
I
D
chemotaxis, adherence, ingestion, digestion
chemotaxis
chemical attraction of phagocytes to microorganisms
adherence
attachment of phagocytes (via receptors, such as Toll-like receptors) to the microorganism (through pathogen-associated molecular patterns, PAMPs), or other materials. Microbes are more readily phagocytized when coated with certain antimicrobial proteins called opsonins such as complements or antibodies. Coating process is called opsonization.