Chapter 21 Flashcards
antimicrobial peptides that inhibit microbial growth
defensins
exposed to foreign substances secrete
pyrogens (proteins)
leukocytes and macrophages
affects multiple organs
systemic lupus erythematosus (SLE)
cause hyperthyroidism
graves’ disease
such as stellate macrophages of liver tissue and microglia of brain tissue also fight tissue infections
phagocytic process
are skin and mucous membranes, along with their secretions
surface barriers
they function as B cell receptor
IgD
B lymphocytes
- are activated when antigens bind to surface receptor
- plasma cells produce antibodies at rate about 200 molecules per second for 4 to 5 days, then they die
ability to stimulate proliferation of specific
lymphocytes
immunogenticity
provide similar mechanical barriers
mucosal lining
in inflammatory chemical release, chemicals are released into injured tissues
histamine released by mast cells key inflammatory chemical
develop from monocytes and are the most robust group of phagocytic cells
macrophages
neutrophils flatten and squeeze between endothelial cells to move into interstitial spaces
diapedesis
are toxic to some bacteria
lipids in sebum and dermcidin in sweat
five major classes:
IgM, IgA, IgD, IgG, and IgE
destroys joints
rheumatoid arthritis
neutralization
- simplest but most effective mechanism
- antibodies block specific sites on viruses or bacterial exotoxins forming antigen-antibody complexes
- this prevents antigens from binding to receptors on cells
- antigens-antibody complexes are then removed by phagocytosis
immunological memory
- between 3 to 6 days
- peaks levels of plasma antibody are reached in 10 days
- antibody evels peak in 2 to 3 days
(antibody-mediated) immunity
humoral
such as alveolar macrophage cells wander through tissue
and fight infection
free macrophages
large, chemically simple molecules (such as plastics) have little or no immunogenicity
antigenic determinants
made up of two systems:
innate and adaptive
ability to react with activated lymphocytes and antibodies
reactivity
fuses with lysosome, forming phagolysosome
phagosome
they can form tumor-like growths
granulomas
innate
- this is a nonspecific defense system
- makes first and second lines of defense against pathogens or
microorganisms - it is a fast response system
peptide molecules produced by neutrophils also help piercing pathogen membranes
defensins
these are agglutinating agent
IgM
they help prevent entry of pathogens
IgA
neutrophils are released from bone marrow
leukocytosis
antibodies are grouped into —
monomer, dimer, and pentamer
antigens can be a complete antigen or —
hapten (incompete)
formed in response to vaccine of dead or
attenuated pathogens
artificially acquried
destroys pancreatic cells
type 1 diabetes mellitus
complements consist of about —
20 blood proteins
TLRs release
cytokines
adaptives
- it is slow response mechanism
- innate and adaptives defenses are interconnected
are non-phagocytic large granular lymphocytes
can kill cancer and virus-infected cells before adaptive immune system is
activated
natural killer (NK) cells
- make 75-85% of antibodies in plasma
- involved in late primary to secondary responses
IgG
eosinophils bind to IgE and release their toxic contents onto prey, lysing it from the outside
parasitic infections by worms
formed in response to actual bacterial or viral infection
naturally acquried
they cause mast cells and basophils to release histamine
IgE
agglutination
- antibodies can bind to two different antigens at the same
- this allows for antigen-antibody complexes to be cross-linked into
large clumps
antimicrobial proteins, phagocytic and other cells to inhibit spread of invaders
second line of defense
sticky mucus that lines digestive and respiratory tract traps
microorganisms
mucin
precipitation
- soluble molecules (instead of cells) are cross-linked into
complexes - complexes precipitate out of solution and then phagocytosed
proteins attack microorganisms directly or affect their ability to reproduce
interferons (IFNs)
mobilizes macrophages and NK cells
IFN-y
inflammatory chemicals act as chemotactic agents to attract neutrophils into the injured area
chemotaxis
is resistant to weak acids and bases, bacterial enzymes, and toxins
keratin
acidity of skin and some mucous secretions inhibits growth; called acid mantle
acid
(cell-mediated) immunity
cellular
macrophages
- widely distributed in connective tissues and lymphoid organs
- activated macrophages transform into phagocytic killer T-cells
- also trigger inflammatory responses to trigger additional defenses
complement fixation
- this a major antibody defense against cellular antigens (bacteria,
mismatched RBCs) - several antibodies are bound close together on same antigen leading to cell lysis
lysozyme of saliva, respiratory mucus, and lacrimal fluid kills many microorganisms; enzymes and acid in stomach kill many microorganism
enzymes
are the most abundant phagocytic cells but die fighting; become
phagocytic on exposure to infectious material
neutrophils
external body membranes (skin and mucosae)
first line of defense
raising body temperature
pyrogens act on hypothalamus (body’s thermostat)
dendritic cells
- found in connective tissues and epidermis
- effectively phagocytize pathogens that enter tissues
endothelial cells of capillaries in inflamed area produce cell
adhesion molecules (CAMs). CAMs attach to neutrophils, causing them to slow down and stick to blood vessel wall
margination
some pathogens are not killed with acidified lysosomal enzymes
tuberculosis bacteria
vasodilation causes hyperemia — leading to redness and heat
hyperemia (excess blood supply)
impairs nerve-muscle connections
myasthenia gravis
damages kidney
glomerulonephritis
is a specific defense mechanism to destroy
pathogens or abnormal cells
adaptive immune system
are molecules that are too small and not immunogenic (not causing immune response)
incomplete antigens (haptens)
destroys white matter myelin
multiple sclerosis
