21.1 Immune System Part 2 Flashcards
White blood cells that ingest and digest (eat) foreign invaders
Ex. neutrophils, macrophages, dendritic cells, mast cells
Phagocytes
Nonphagocytic, large granular lymphocytes that police blood and lymph
Kill by inducing apoptosis in cancer cells and virus-infected cells
Secrete potent chemicals that enhance inflammatory response
Natural killer cells
Programmed cell death
Apoptosis
Triggered whenever we have an injury
Due to trauma, heat, irritating chemicals, infections
Inflammation
Prevents spread of damaging agents
Disposes of cell debris and pathogens
Alerts adaptive immune system
Sets the stage of repair
Benefits of inflammation
Heat
Redness
Swelling
Pain
*Impairment of function
Signs of inflammation
- Inflammatory chemical release
- Vasodilation and increased vascular permeability
- Phagocyte mobilization
Stages of inflammation
Proteins that enhance innate defense by hindering microorganisms ability to reproduce, or attacking the microorganism directly
Antimicrobial proteins
General term for chemical messengers that influence cell development, differentiation, and responses in the immune system
Cytokines
Proteins that play a role in the immune system
Interferons
Bloodborne proteins; When activated they lyse mircroorganisms, enhance phagocytosis, intensify inflammatory responses
Complement proteins
Abnormally high body temperature that is systemic response to invading microorganisms
98.6 F or 37 C
Pyrogens secreted
Fever
- Causes liver and spleen to sequester iron and zinc that are needed by microorganisms
- Increases metabolic rate, which increases rate of repair
Benefits of fever
Specific defense mechanism that eliminates almost any pathogen or abnormal cell in body
Must be primed by initial exposure
Specific, systemic, memory
Adaptive immune system
Antibody mediated immunity
Provided by antibodies in the body’s “humors” or fluids (blood and lymph)
Bind to extracellular targets to inactivate and mark them for destruction by phagocytes
Humoral immunity
Cell mediated immunity
Provided by lymphocytes themselves and had cellular targets
Can act directly or indirectly,
Cellular immunity
Substances that can mobilize the adaptive defenses, provoking an immune response
Most are large, complex molecules that are foreign
Antigens
Involved in adaptive immune system
Provide humoral immunity
Bind temporarily to target (extracellular targets)
B lymphocytes
Involved in adaptive immune system
Provide cellular immunity
T lymphocytes
Play an essential auxillary role in immunity; present antigens to T cells
Antigen presenting cells (APCs)
- Origin
- Maturation
- Seeding secondary lymphoid organs and circulation
- Antigen encounter and activation
- Proliferation and differentiation
Life cycle of Lymphocytes
make sheet
Produced by B lymphocytes
Circulate freely in the body
Inactivate and tag antigens
Capable of binding specifically with antigen detected by B cells
Aka - Immunoglobulins
Antibodies
B cells are activated when ______ bind to surface receptors
Antigens
Antibody secreting effector B cells
Antibodies circulate in blood or lymph
Antibodies bind to free antigens, marking them for destruction
Plasma cells
Provide immunological memory
Mount an immediate response to future exposure
Memory B cells
Cell proliferation and differentiation upon exposure to antigen for the first time
Lag period of 3-6 days
Peak levels of plasma antibody
Primary immune response
Re-exposure to same antigen gives faster, more prolonged, more effective response
Provide immunological memory
Secondary immune response
Occurs when B cells encounter antigens and produce specific antibodies against them
Ex. infection, vaccine
Active humoral immunity
Occurs when ready-made antibodies are introduced into body
B cells not challenged by antigens
Immunological memory does not occur
Protection ends when antibodies degrade
Ex. antibodies passed from mother to fetus, injection of exogenous antibodies
Passive humoral immunity
2 identical heavy chains, 2 identical light chains; Hinge region in middle
Four looping polypeptide chains linked by disulfide bonds
Antibody monomer
At one end of each arm of antibody
Variable region
Area that determines antibody class and serves common functions in all antibodies
Constant region
Antibodies block specific sites on viruses or bacterial exotoxins
Prevent antigens from binding to receptors on tissue cells
Neutrilization
Antibodies can bind same determinant on two different antigens at the same time
Agglutination
Soluble molecules are cross-linked into large lattice-like clumps
Precipitation
mechanisms antibody action
Act against target cell
Direct - killing infected cells
Indirect - releasing chemicals that enhance inflammatory response or activating other lymphocytes or macrophages
T cell lymphocytes
Type of T cell; Naive form
When active they become:
Helper T cell (TH) - activate other T cells and macrophages
Regulatory T cell (Treg) - moderate immune response
CD4 T cells
Type of T cell
When active become:
Engulf antigens and present fragments of antigens to T cells for recognition via major histocompatibility complex
Major types: dendritic cells, macrophages, B cells
Antigen presenting cells (APC)
Process of APC cells engulfing antigens and presenting fragments of antigens to T cells for recognition
2 classes: MHC class 1, MHC class 2
Major histocompatibility complex (MHC) proteins
Results when immune system loses ability to distinguish self from foreign
Autoimmune disease
Production of autoantibodies and sensitized cytotoxic T cells that destroys body tissues
Ex. rheumatoid arthritis, grave’s disease, T1 diabetes
Autoimmunity
Immune response to perceived (otherwise harmless) threat that cause tissue damage
Distinguished by:
1. Time in course
2. Whether antibodies or T cells are involved
Hypersensitivities
Type 1 HS
Begin in seconds after contact with allergen
Caused by antibodies
Response = anaphylactic shock
Usually seen with allergens
Ex. bee sting
Immediate hypersensitivity
Type IV HS
Slow onset (1-3 days)
Mechanism depends on helper T cells
Macrophages and cytotoxic T cells cause damage
Ex. allergic contact dermatitis (poison ivy)
Delayed hypersensitivity
