Flashcards in Lymphatic/Immune 2 Deck (68):
1
Mobilization of Defenses
Leukocytes deployed
2
Margination
Leukocytes adhere to blood vessel walls
3
Diapedesis
Leukocytes squeeze between endothelial cells into tissue space
4
Containment and Destruction of Pathogens
Fibrinogen in tissue clots to trap microbes
Heparin prevents clotting at side of injury
Neutrophils respond and kill microbes via phagocytosis
5
Tissue Cleanup
1. Monocytes arrive in 8-12 hours and become macrophages
2. Edema slows venous flow and increases lymphatic flow to remove bacteria and debris
3. Pus is formed
6
Tissue Repair
Blood platelets and endothelial cells secrete cytokine PDGF that stimulates fibroblasts to multiply and synthesize collagen
7
Pus
Dead phagocytes, damaged tissue cells, and fluid
8
Abscess
Accumulation of pus in a confined space not open to the outside
9
Ulcer
Open sore
10
Immunity
Body's ability to defend itself against specific foreign material or organisms
11
Immune Specificity
Recognize self and nonself
12
Immune Memory
2nd encounter produces even more rigorous response
13
T Cells
Mature in the thymus
NK cells attack antigens
Effective against fungi, viruses, parasites, cancer, and tissue transplants
14
B Cells
Mature in the bone marrow
Antibody-mediated response
Effective against bacteria
15
Antigens
Molecules or bits of foreign materials
16
Antigen Immunogenicity
Ability to provoke immune responses
17
Antigen Reactivity
Ability to react to cells or antibodies
18
Chemical Nature of Antigens
Large, complex molecules, usually proteins
19
Epitopes
Small part of antigen that triggers immune response
20
Hapten
Smaller substance that cannot trigger an immune response unless attached to a body protein
Lipid of poison ivy
21
MHC-I Molecules
Built into cell membrane of all cells except for red blood cells
22
MHC-II Molecules
Markers seen only on membrane of antigen presenting cells
(Macrophages, B cells, thymus cells)
23
If cell is infected with virus...
MHC-I contains bits of virus marking cell so T Cells recognize
24
If antigen presenting cells (macrophages or B cells) ingest foreign proteins...
They will display as part of MHC-II
25
Histocompatibility Testing
Similarity of MHC antigens on body cells of different individuals
Tissue typing must be done before any organ transplant
Can help identify biological parents
26
Pathways of Antigen Processing
B and T cells must recognize a foreign antigen before beginning their immune response
B cells can bind to antigen in extracellular fluid
T cells can only recognize fragments of antigens that have been processed and presented to them as part of a MHC molecule
27
Cytokines
Small protein hormones involved in immune responses
Secreted by lymphocytes and antigen-presenting cells
28
Lymphocytes
80% T Cells (cell mediated): involves activation of phagocytes, T Cells
15% B Cells (antibody mediated): antibody production
5% NK cells (nonspecific immunity)
29
T Lymphocytes
Immunocompetent cell: antigen receptors in place
30
Negative Selection of T Cells in Thymus
1. Must bind to reticular epithelium cell
2. Must not react to self antigens
Failing either will result in clonal deletion or anergy
1/100 emerge immunocompetent
31
Clonal Deletion
Destruction of offending T Cell clone
32
Anergy
Inactive state, alive but unresponsive
33
Positive Selection of T Cells in Thymus
1. Recognize MCH or reticular epithelium cell
2. Do not react to self antigens
Divide rapidly and form a clone of T Cells with identical receptors for antigen
Only 2% pass
34
Cellular Immunity
T Lymphocytes attack and destroy foreign cells and diseased host cells
35
Cytotoxic T Cells
Carry out attack
Display CD8 on surface
Recognize antigen fragments associated with MCH-I molecules
36
Regulatory T Cells
Limit cell mediated attack
37
Memory T Cells
Provide immunity from future exposure to antigen
38
Cytotoxic T Cell Recognition
Antigen presentation by MHC-I proteins
39
Cytotoxic Elimination of Invaders
1. Secrete granules containing perforin that punch holes in large cells
2. Secretes lymphotoxin that activates enzymes in the target cell, causing its DNA to fragment
3. Secretes gamma-interferon to activate phagocytic cells
40
Helper T Cells
Display CD4 on surface
Costimulates all other lymphocytes and secretes cytokines
41
T Cell Activation
Role of MHC-II proteins
Found only on antigen presenting cells
Stimulate helper T cells
42
T Cell Activation
1. Binding of helper T cells (CD4 cells) to abnormal peptides ingested and displayed on MCH-II
2. Costimulation via a cytokine
43
Attack Phase of Helper T Cells
Secrete interleukins
Coordinate humoral and cellular immunity
44
Memory T Cells
T Cells from a clone that did not turn into cytotoxic T Cells during a cell-mediated response
45
T Cell Recall Response
Available for swift response if a 2nd exposure should occur
46
Recognition T Cells
As pathogen disappears, slows down immune reaction
Prevents autoimmune diseases
47
Antibody-Mediated Immunity
1. Millions of different B Cells that can recognize different antigens and respond
2. B Cells sit and let antigens be brought to them
3. Once activated, differentiate into plasma cells
4. Antibodies circulate in lymph and blood
48
Antibody Structure
Glycoproteins called immunoglobins
4 polypeptide chains (2 heavy and 2 light)
IgG, IgA, IgM, IgD, and IgE tips form antigen binding sites
49
IgA
Monomer in plasma
Dimer in mucus, saliva, tears, milk, intestinal secretions
Prevents adherence to epithelia
50
IgD
Monomer
B Cell membrane antigen receptor
51
IgE
Monomer
Tonsils, skin, mucus membranes
Stimulates release of histamines and attracts eosinophils
52
IgG
Monomer
75-85% circulating
Crosses placenta to fetus
Secondary immune response
Binds complement proteins
53
IgM
Monomer
B Cell membrane
Antigen receptor
Pentamer in plasma
Agglutination
54
Somatic Recombination
Shuffling DNA segments to form new combinations of base sequences to produce antibody genes
55
Antibody Actions
1. Neutralization of antigen by blocking effects of toxins or preventing its attachment to body cells
2. Immobilize bacteria by attacking cilia/flagella
3. Agglutinate and precipitate antigens by cross-linking them, causing clumping and precipitation
4. Complement activation
5. Enhancing phagocytosis through precipitation, complement activation, or opsonization
56
Monoclonal Antibodies
Antibodies against a particular antigen can be harvested from the blood
57
Primary Immune Response
First exposure to antigen response is steady and slow
Memory cells may remain for decades
58
Secondary Immune Response with Second Exposure
Thousands of memory cells proliferate and differentiate into plasma cells and cytotoxic T cells
Recognition and removal occurs quickly
59
Natural Active Immunity
Produces memory cells
Production of one's own antibodies or T Cells as a result of infection or natural exposure to antigen
60
Artificial Active Immunity
Produces memory cells
Production of one's own antibodies or T Cells as a result of vaccination
61
Natural Passive Immunity
Through placenta or milk
Temporary, fetus acquires antibodies from mother
62
Artificial Passive Immunity
Snakebite, rabies, tetanus
Temporary, injection of immune serum (antibodies)
63
Hypersensitivity
Excessive immune reaction against antigens that most people tolerate (allergens)
64
Asthma
Most common chronic illness in children
Inhaled allergens, histamines, dyspnea
65
Anaphylactic Shock
Bronchial constriction, dyspnea, vasodilation, shock, death
Treatment is epinephrine
66
Type II Hypersensitivity
IgG or IgM binds to antigens or cell surface receptors to lyse or overstimulate
67
Type III Hypersensitivity
Widespread antigen-antibody complexing
Complexes trigger intense inflammation
68