Ch 45 Immune System Flashcards
(95 cards)
1
Q
What is the primary function of the immune system?
A
Protects the body against disease-causing organisms and certain toxins.
2
Q
What are pathogens?
A
Disease-causing organisms, including viruses, bacteria, fungi, and protozoa.
3
Q
What is immunology?
A
The study of internal defense systems of humans and other animals.
4
Q
What are the two main types of immune responses?
A
- Nonspecific immune responses
- Specific immune responses
5
Q
What is innate immunity?
A
Nonspecific immune responses providing general and immediate protection against pathogens.
6
Q
What is adaptive immunity?
A
Specific immune responses that target distinct antigens recognized as foreign or dangerous.
7
Q
What are antibodies?
A
Highly specific proteins produced by the immune system that recognize and bind to specific antigens.
8
Q
What does immunological memory refer to?
A
The immune system’s ability to remember foreign or dangerous molecules and respond more strongly to repeated encounters.
9
Q
What is the ‘danger model’ in the immune system?
A
A concept that describes how the immune system responds to danger signals from damaged or stressed cells.
10
Q
What are DAMPs?
A
Damaged associated molecular patterns recognized by the immune system from stressed or damaged cells.
11
Q
What are PAMPs?
A
Pathogen-associated molecular patterns recognized by Toll-like receptors.
12
Q
What are physical barriers in nonspecific immune responses?
A
- Cuticle or skin
- Mucus
- Chitinous exoskeletons
13
Q
What is the role of phagocytes in the immune system?
A
Phagocytes engulf and digest pathogens and debris.
14
Q
What are natural killer (NK) cells?
A
Large granular lymphocytes that destroy virus-infected and foreign or altered cells.
15
Q
What are cytokines?
A
Signaling molecules that regulate interactions between cells in the immune system.
16
Q
What are the three actions of cytokines?
A
- Autocrine
- Paracrine
- Endocrine
17
Q
What is the complement system?
A
A system of proteins that enhances the inflammatory response and helps eliminate pathogens.
18
Q
What are the signs of inflammation?
A
- Heat
- Swelling
- Redness
- Pain
19
Q
What are the main processes involved in the inflammatory response?
A
- Vasodilation
- Increased capillary permeability
- Increased phagocytosis
20
Q
What are the two main types of cells involved in specific immune responses?
A
- Lymphocytes
- Antigen-presenting cells
21
Q
What are the three types of lymphocytes?
A
- T lymphocytes
- B lymphocytes
- Natural killer (NK) cells
22
Q
What is the role of T lymphocytes?
A
Responsible for cell-mediated immunity.
23
Q
What is the primary function of B lymphocytes?
A
Responsible for antibody-mediated immunity.
24
Q
What happens to B cells when they are activated?
A
They divide and differentiate into plasma cells that produce antibodies.
25
What is the significance of memory B cells?
They continue to produce antibodies after an infection has been overcome.
26
What is the process of positive selection in T cells?
T cells are allowed to mature if they recognize self-antigens.
27
What is the function of antigen-presenting cells (APCs)?
Activate T helper cells by displaying foreign antigens.
28
True or False: T cells mature in the bone marrow.
False. T cells mature in the thymus.
29
What are Toll-like receptors?
Cell-surface receptors that recognize pathogen-associated molecular patterns (PAMPs).
30
What role do macrophages play in the immune system?
They are phagocytes that can engulf pathogens and secrete cytokines.
31
What is the effect of type I interferons?
Inhibit viral replication and activate natural killer cells.
32
What is the purpose of tumor necrosis factors (TNF)?
Initiate inflammatory responses against pathogens.
33
What is chemotaxis?
The attraction of white blood cells to the site of infection.
34
What is the role of mast cells in inflammation?
They release histamine and other compounds that cause vasodilation and increase capillary permeability.
35
Fill in the blank: The immune system uses _______ to distinguish between self and nonself.
cell signaling
36
What is the significance of granzymes produced by NK cells?
They enter target cells to activate apoptosis.
37
What are antigen-presenting cells (APCs)?
APCs activate T helper cells by displaying foreign antigens and their own surface proteins. They include macrophages, dendritic cells, and B cells.
## Footnote
APCs are inactive until their pattern-recognition receptors recognize PAMPs on pathogens.
38
What is the role of macrophages in the immune response?
Macrophages digest pathogens, retain some antigens, and present them to T cells. They also secrete cytokines and enzymes that destroy bacteria.
39
Where are dendritic cells located and what is their function?
Dendritic cells are located throughout the body, including the skin, and are specialized to process, transport, and present antigens to T cells.
40
What is the major histocompatibility complex (MHC)?
MHC is a group of polymorphic genes that encode MHC proteins, allowing the immune system to distinguish self from nonself.
41
What do Class I MHC genes encode?
Class I MHC genes encode self-antigens expressed on the surface of most nucleated cells, binding with foreign antigens to present them to T cytotoxic cells.
42
What do Class II MHC genes encode?
Class II MHC genes encode glycoproteins expressed on antigen-presenting cells, presenting complex antigens to T helper cells.
43
Define cell-mediated immunity.
Cell-mediated immunity is when specific T cells are activated to destroy cells infected with viruses or other intracellular pathogens.
44
Define antibody-mediated immunity.
Antibody-mediated immunity is when specific B cells are activated to multiply and differentiate into plasma cells that produce antibodies.
45
What are the two populations of T cells involved in cell-mediated immunity?
The two populations are T cytotoxic (T_C) cells and T helper (T_H) cells.
46
What is the function of T_C cells?
T_C cells destroy pathogen-infected cells by releasing cytotoxic substances like perforins and granzymes.
47
What is the significance of activated B cells in antibody-mediated immunity?
Activated B cells multiply and give rise to clones of cells, which differentiate into plasma cells producing specific antibodies.
48
What are plasma cells?
Plasma cells are B cells that produce vast quantities of antibodies into the lymph and blood.
49
What is the structure of an immunoglobulin (antibody)?
An immunoglobulin consists of four polypeptide chains: two identical heavy chains and two identical light chains, forming a Y shape.
50
What are the Fab and Fc fragments of an antibody?
Fab fragments are the antigen-binding portions, while Fc fragments interact with immune cells and molecules of the complement system.
51
What are the five classes of antibodies?
* IgG
* IgM
* IgA
* IgD
* IgE
52
What role does IgG play in the immune system?
IgG makes up about 75% of human immunoglobulins, crosses the placenta, and protects the fetus.
53
What is the primary antibody produced during a primary immune response?
IgM is the principal antibody synthesized during a primary immune response.
54
What is active immunity?
Active immunity develops as a result of exposure to antigens, either naturally after recovery from a disease or artificially through vaccination.
55
What is passive immunity?
Passive immunity is a temporary condition that develops when an individual receives antibodies produced by another person or animal.
56
What is the role of memory cells in the immune response?
Memory cells remain in the body after an infection and are responsible for long-term immunity by producing antibodies upon re-exposure to the antigen.
57
What is the clonal selection theory?
Clonal selection theory states that a lymphocyte has specific receptors for an antigen on its surface, and binding activates the lymphocyte to divide and form a clone.
58
What are monoclonal antibodies?
Monoclonal antibodies are identical antibodies produced by cells cloned from a single cell, specific for a single antigenic determinant.
59
What triggers the primary immune response?
The first exposure to an antigen triggers the primary immune response, characterized by a latent period followed by a logarithmic phase.
60
What is the predominant antibody in a secondary immune response?
IgG is the predominant antibody in a secondary immune response, which is more rapid and intense than the primary response.
61
What are tumor-specific antigens?
Tumor-specific antigens are unique to cancer cells and recognized by T cells.
62
What is the role of NK cells in cancer immunity?
NK cells recognize and destroy cancer cells by launching an immune response against them.
63
What cells of the immune system recognize antigens on cancer cells?
Macrophages, T cells, NK cells, and other cells of the immune system
## Footnote
These cells launch an immune response against cancer cells.
64
What do macrophages produce to aid in immune response?
Cytokines, including TNFs
## Footnote
TNFs are tumor necrosis factors that play a role in inflammation.
65
What is the role of dendritic cells in cancer immunity?
Dendritic cells find cancer antigens and present them to T cells in lymph nodes.
66
What happens when T cells are activated in response to cancer?
They form a clone and release interferons, attracting and activating macrophages and NK cells.
67
What mechanisms can some cancer cells use to evade T cell response?
Decrease expression of class I MHC molecules and do not produce co-stimulatory molecules.
68
What is a potential downside of conventional cancer treatments like chemotherapy and radiation?
They destroy normal cells as well as cancer cells.
69
What is Herceptin?
A monoclonal antibody drug that blocks growth factors stimulating cancer cell proliferation.
70
What are angiogenesis inhibitors used for?
They are being tested as potential cancer treatments.
71
What types of vaccines against cancer are being developed?
Vaccines that contain cancer cells, antigens, or cancer cell DNA.
72
What is immunodeficiency disease?
A condition resulting from the absence or failure of a component of the immune system.
73
What are Severe Combined Immunodeficiency Syndromes (SCIDs)?
Sex-linked and autosomal recessive disorders that result in multiple infections.
74
What is DiGeorge syndrome?
A condition where the thymus is reduced or absent, leading to a deficiency of T cells.
75
What is the main cause of acquired immunodeficiency?
Protein malnutrition or chemotherapy.
76
What is HIV?
Human immunodeficiency virus first discovered in 1983, causing AIDS.
77
What type of virus is HIV?
A retrovirus that uses reverse transcriptase to convert RNA into DNA.
78
How is HIV primarily transmitted?
By semen or blood.
79
What cells are the first target of HIV in the body?
Dendritic cells in the mucous membranes.
80
What does HIV attach to in T helper cells?
The CD4 membrane protein.
81
What is the initial clinical manifestation of HIV infection?
Various unusual opportunistic infections.
82
What is the role of AZT in HIV treatment?
Blocks reverse transcriptase, although resistant strains can develop.
83
What is graft rejection?
An immune response in which T cells destroy transplanted tissue due to mismatched MHC antigens.
84
What are the two stages of graft rejection?
1. Sensitization stage
2. Effector stage
85
What is Rh incompatibility?
A maternal-fetal blood type incompatibility that can cause hypersensitivity.
86
What happens if an Rh-negative mother has an Rh-positive fetus?
The mother may produce antibodies against antigen D after the first pregnancy.
87
What is erythroblastosis fetalis?
A disease resulting from Rh incompatibility that can lead to fetal red blood cell destruction.
88
What is the treatment for Rh-negative women after childbirth?
RhoGAM, which clears Rh-positive RBCs from the mother’s blood.
89
What are allergens?
Mild antigens that trigger immune responses only in some individuals.
90
What is the first step in the allergic reaction process?
Sensitization, where macrophages degrade the allergen and present it to T cells.
91
What is systemic anaphylaxis?
A severe allergic reaction that can lead to widespread vasodilation and may be fatal.
92
What type of antibodies are produced during an allergic reaction?
IgE immunoglobulins.
93
What characterizes autoimmune diseases?
The body attacks its own tissues due to hypersensitivity to self-antigens.
94
What are some examples of autoimmune diseases?
Rheumatoid arthritis, multiple sclerosis, insulin-dependent diabetes.
95
What genetic factors are associated with autoimmune diseases?
They seem to have a genetic link and may be triggered by infections.
