CH4-S1 Flashcards
Immunity is _______
resistance to disease
Immune system has two intrinsic systems called: ________
Innate defense system, acquired(adaptive) defense system
Innate defense system has two lines of defense:
First - __________ ,Second - __________
external body membranes (skin and mucosa), antimicrobial proteins, phagocytes, and other cells
Second line of defense in innate defense system can ____________
Inhibit spread of invaders. Inflammation is the most important mechanism
Third line of defense attacks particular foreign substances is _______
Adaptive defense system
Innate defenses include: _________
Surfaces barriers - skin, mucous membranes
Internal defenses - Phagocytes, natural killer cells, inflammation response, antimicrobial proteins, fever
Adaptive defenses include: _________
Humoral immunity - B cells
Cellular immunity - T cells
_____ is the most abundant phagocytes.
Neutrophils
Phagocytes: ______ develop from monocytes - chief phagocytic cells - robust cells; has fixed or free types
macrophages
_________(make more susceptible to phagocytosis) marks pathogens - coating by complement proteins or antibodies
Opsonization
Cytoplasmic extensions bind to and engulf particle in vesicle called ________.
phagosome
Phagosome fuses with lysosome ________
phagolysosome
Describe the process of phagocytosis
- Phagocyte adheres to pathogens or debris.
- Phagocyte forms pseudopods that eventually engulf the particles, forming a phagosome.
- Lysosome fuses with the phagocytic vesicle, forming a phagolysosome.
- Lysosomal enzymes digest the particles, leaving a residual material.
- Exocytosis of the vesicle removes indigestible and residual material.
Helper T cells cause release of enzymes of ________, which kill pathogens resistant to lysosomal enzymes by ______
respiratory burst,
Releasing cell-killing free radicals
Producing oxidizing chemicals (e.g., H2O2)
Increasing pH and osmolarity of phagolysosome
_________: nonphagocytic large granular lymphocytes;
Attack cells that lack “self” cell-surface receptors: induce ______in cancer cells and virus-infected cells
Natural Killer (NK) Cells, apoptosis
Cardinal signs of acute inflammation:________
Redness
Heat
Swelling
Pain
Sometimes have impairment of function
Kinins, prostaglandins (PGs), and complement ________; causes redness and heat of inflamed region
Dilate local arterioles (hyperemia)
_______ increase capillary permeability and produce exudate to tissues
Edema
Phagocyte Mobilization: ______lead; _______follow. As attack continues, _____arrive.
Neutrophils, macrophages, monocytes
Innate -> Internal defenses
Steps for phagocyte mobilization:
1. _________: release of neutrophils from bone marrow in response to _____ from injured cells
2. ________: neutrophils cling to to capillary wall in inflamed area in response to CAMs
3. ________of neutrophils (Neutrophils flatten and squeeze out of capillaries)
4. ________: inflammatory chemicals promote positive chemotaxis of neutrophils (Neutrophils follow
chemical trail)
Leukocytosis, leukocytosis-inducing factors, Margination, Diapedesis, Chemotaxis
Antimicrobial Protein include _____and _____. Some attack microorganisms directly. Some hinder microorganisms’ ability to reproduce.
interferons, complement proteins
_________: family of immune modulating proteins (have slightly different physiological effects) ; it is secreted by viral-infected cells to “warn” neighboring cells
Interferons
Give two functions of interferons
block viral reproduction and degrade viral RNA, activate NK cells and macrophages
Artificial interferons used to treat _______
hepatitis C, genital warts, multiple sclerosis, hairy cell leukemia
The interferon mechanism against viruses
- Virus enters cell
- Interferon genes switch on.
- Cell produces interferon molecules
- Interferon binding stimulates cell to turn on genes for antiviral proteins.
- Antiviral proteins block viral reproduction
_______: major mechanism for destroying foreign substances; ~____ blood proteins that circulate in inactive form; unleashes inflammatory chemicals that amplify all aspects of inflammatory response ; kills bacteria and certain other cell types by _____; enhances _____defenses
Complement System, 20, cell lysis, both innate and adaptive
Three pathways to complement activation: _________
Classical pathway (complement fixation), Lectin pathway (produced by innate system to recognize foreign invaders
), Alternative pathway
Common terminal complement pathway initiated: _______
Enhances inflammation, promotes phagocytosis, causes cell lysis
Leukocytes and macrophages exposed to foreign substances secrete _______ and act on body’s thermostat in hypothalamus, raising body temperature
pyrogens
Benefits of moderate fever: ______
causes liver and spleen to sequester iron and zinc (needed by microorganisms), increases metabolic rate to have faster repair
Adaptive defenses’ functions and properties: _______________
Protects against infectious agents and abnormal body cells
Amplifies inflammatory response
Activates complement
Must be primed by initial exposure to specific foreign substance
Specific – recognizes and targets specific antigens
Systemic – not restricted to initial site
Have memory – stronger attacks to “known” antigens
Two separate, overlapping arms:
Humoral (antibody-mediated) immunity
Cellular (cell-mediated) immunity
_______immunity has extracellular targets.
______ immunity has cellular targets
Humoral, Cellular
_______ are substances that can mobilize adaptive defenses and provoke an immune response. Targets of all adaptive immune responses. Most are large, complex molecules not normally found in body (nonself).
Antigens
Complete antigens have important functional properties:
______: ability to stimulate proliferation of specific lymphocytes
_______: ability to react with activated lymphocytes and antibodies released by immunogenic reactions
Immunogenicity, Reactivity
Give examples of complete antigens
foreign protein, polysaccharides, lipids, and nucleic acids
Antibodies and lymphocyte receptors bind to ______, to mobilize several different lymphocyte populations
and form different kinds of antibodies against them
antigenic determinants (immunogenic)
List 3 cells of the adaptive immune system
B lymphocytes (B cells)—humoral immunity
T lymphocytes (T cells)—cellular immunity
Antigen-presenting cells (APCs)—Do not respond to specific antigens, play essential auxiliary roles in immunity
List five general steps of lymphocyte development, maturation, and activation
- Origin
-Both B and T lymphocyte precursors originate in red bone marrow. - Maturation
-Lymphocyte precursors destined to become T cells migrate (in blood) to the thymus and mature there,
-B cells mature in the bone marrow.
-During maturation, lymphocytes develop immunocompetence and self-tolerance. - Seeding secondary lymphoid organs and circulation
-Immunocompetent but still naive lymphocytes leave the thymus and bone marrow.
-They “seed” the secondary lymphoid organs and circulate through blood and lymph. - Antigen encounter and activation
-When a lymphocyte’s antigen receptors bind its antigen, that lymphocyte can be activated. - Proliferation and differentiation
-Activated lymphocytes proliferate (multiply) and then
differentiate into effector cells and memory cells.
-Memory cells and effector T cells circulate continuously in
the blood and lymph and throughout the secondary
lymphoid organs.
T cells mature in ______under negative and positive selection pressures (“tests”):
______: Selects T cells capable of recognizing self-MHC proteins (MHC restriction); failures will be destroyed by apoptosis
______: Prompts apoptosis of T cells that bind to self-antigens displayed by self-MHC, ensures self-tolerance
thymus, Positive selection, Negative selection
Describe the adaptive defenses (cellular immunity) process / Positive & negative selection
T cells will first undergo positive selection. They must recognize self-MHC. This will result in survival. Survivors proceed to negative selection. However, if they are fail to recognize self-MHC will result in apoptosis (death by cell suicide).
T cells must not recognize self-antigens negative selection, which results in survival and continued maturation. On the opposite, recognizing self-antigen results in apoptosis. This
eliminates self-reactive T cells that could cause autoimmune diseases.
B cells mature in _______. Positively selected if successfully make antigen receptors. Those that are self-reactive will be eliminated by apoptosis (clonal deletion).
red bone marrow
________:naive lymphocyte’s first encounter with antigen selected for further development. If correct signals present, lymphocyte will complete its differentiation.
Clonal selection
Describe the adaptive defenses (humoral immunity) process
Primary response; Antigen binding to a receptor on a
specific B lymphocyte -> (Activated B cells) Proliferation to form a clone -> plasma cells (effector B cells) secrete
antibody molecules & memory B cell—primed to respond
to same antigen
Lag period of primary immune response is _____.
three to six days
What is the use of vaccination?
Active humoral immunity when B cells encounter antigens and produce specific antibodies against them. (Artificially acquired)
Two types of _______immunity:
Naturally acquired—response to bacterial or viral infection
Artificially acquired—response to vaccine of dead or attenuated pathogens
active humoral
_______:
-Readymade antibodies introduced into body
-B cells are not challenged by antigens
-Immunological memory does not occur
-Protection ends when antibodies degrade
Passive Humoral Immunity
Two types of _______immunity:
Naturally acquired—antibodies delivered to fetus via placenta or to infant through milk
Artificially acquired—injection of serum, such as gamma globulin
Protection immediate but ends when antibodies naturally degrade in body
Passive Humoral Immunity
______ is gamma globulin portion of blood;
proteins secreted by plasma cells; antibodies; grouped into one of five Ig classes
Immunoglobulins
Antibody classes: ______
IgM, IgA, IgD, IgG, or IgE
______ determine antibody class
Constant regions of stem in antibody
Function(s) of IgA
Helps prevent entry of pathogens
Function(s) of IgD
B cell receptor
Function(s) of IgG
Monomer; 75–85% of antibodies in plasma
From secondary and late primary responses
Crosses placental barrier
Function(s) of IgE
active in some allergies and parasitic infections (causes mast cells and basophils to release histamine)
____cells can switch antibody classes but retain antigen specificity
-IgM at first; then IgG
-Almost all secondary responses are IgG
B
Antibody Targets and Functions
-Antibodies inactivate and tag antigens; do not destroy them
(Form antigen-antibody (immune) complexes)
Defensive mechanisms used by antibodies:
-Neutralization and agglutination (the two most important)
-Precipitation and complement fixation
Neutralization: _______
masks dangerous parts of bacterial exotoxins; viruses
Agglutination: ______
cell-bound antigens
T cell Activation: Proliferation and Differentiation:__________________________________________________________________________________________________________
-Primary T cell response peaks within a week
-T cell apoptosis occurs between days 7 and 30
(Benefit of apoptosis: activated T cells are a hazard – produce large amount inflammatory cytokines cause hyperplasia, cancer)
-Effector activity wanes as amount of antigen declines
-Memory T cells remain and mediate secondary responses
________: chemical messengers of immune system; mediate cell development, differentiation, and responses in immune system
Cytokines
