Chapter 8: The Immune System Flashcards
______________ is composed of defences that are always active against infection, but lack the ability to target specific invaders.
Innate immunity
Because its lack of ability to target specific invaders, the innate immune system is a _____________ immunity.
Nonspecific immunity
__________ or ___________ immunity refers to the defences that target a specific pathogen. This system is slower to act, but can maintain immunological memory of an infection to mount a faster attack in subsequent infections.
Adaptive/specific immunity
The ____________ immunity system acts near entry points into the body and is always at the ready.
Innate immunity
If the innate immunity system fails to contain a pathogen, the ______________ kicks in, mounting a later but highly targeted attack against the specific invader.
Adaptive immunity
____________ system includes antimicrobial molecules and various phagocytes (cells that ingest and destroy pathogens). These cells, such as dendritic cells and macrophages, also activate an inflammatory response, secreting proteins called cytokines and trigger an influx of immune cells from the blood. Among the recruits are more phagocytes-notably monocytes (which can mature into macrophages) and neutrophils.
Innate immune system
_____________ system features B-cells and T-cells.
Adaptive immune system
Activated B-cells secrete ____________ molecules that bind to antigens-specific components unique to a given invader - and destroy the invader directly or mark it for attack by others.
Antibody molecules
___________ recognize antigens displayed on cells. Some ___________ help to activate B-cells and other T-cells; other ___________ directly attack infected cells.
T-cells
The ____________ produces all of the leukocytes (white blood cells) that participate in the immune system through the process os hematopoiesis.
Bone marrow
The __________ is a location of blood storage and activation of B-cells.
Spleen
B-cells can turn into __________ cells to produce antibodies as part of the adaptive immunity.
Plasma cells
Because the naive B-cells dissolve and act in the blood (rather than within cells), this division of adaptive immunity is called ____________ immunity.
Humoral immunity
T-cells, another class of adaptive immune cells, mature in the __________.
Thymus
__________ is a small gland just in front of the pericardium, the sac that protects the heart.
Thymus
T-cells are the agents of _____________ immunity because they coordinate the immune system and directly kill virally infected cells.
Cell-mediated immunity
____________, a major component of the lymphatic system, provide a place for immune cells to communicate and mount an attack; B-cells can be activated here as well.
Lymph nodes
Other immune tissue is found in close proximity to the digestive system, which is a site of potential invasion by pathogens. These tissues are commonly called _______________________ (_________).
Gut-associated lymphoid tissue
The gut-associated lymphoid tissue (GALT) include the __________ and __________ in the head.
Tonsils and adenoids
The gut-associated lymphoid tissue (GALT) include the _____________ in the small intestine.
Peyer’s patch
The gut-associated lymphoid tissue (GALT) include the lymphoid aggregates in the ___________.
Appendix
The _________ acts as a storage area for white blood cells and platelets, a recycling centre for red blood cells, and a filter of blood and lymph for the immune system.
Spleen
Both granulocytes and granulocytes come from a common precursor: ________________ cells.
Hematopoietic stem cells
The granules in granulocytes contain toxic enzymes and chemicals, which can be released by _____________, and are particularly effective against bacterial, fungal, and parasitic pathogens.
Exocytosis
Granulocytes include cells such as ___________, ____________, and ____________.
Neutrophils, eosinophils, and basophils
____________ include the lymphocytes, which are responsible for antibody production, immune system modulation, and targeted killing of infected cells.
Agranulocytes
__________, which are phagocytic cells in the bloodstream, are also considered agranulocytes.
Monocytes
Macrophages with specific names:
- __________ in the central nervous system
- ____________ in the skin
- ____________ in bones
- Microglia in the CNS
- Langerhans cells in the skin
- Osteoclasts in the bone
The specific immune system can be divided into _____________ immunity (driven by B-cells and antibodies) and _____________ immunity (driven by T-cells).
- Humoral immunity
- Cell-mediated immunity
Our first line of defence is the ________ (____________).
Skin (integument)
Antibacterial enzymes called ___________ can be found on the skin.
Defensins
The respiratory passages are mucous membranes, lined with _________ to trap particulate matter and push it up toward the oropharynx, where is can be swallowed or expelled.
Cilia
Several other mucous membranes, including those around the eye and in the oral cavity, produce a nonspecific bacterial enzyme called ___________, which is secreted in tears and saliva, respectively.
Lysozyme
The ___________ system consists of a number of proteins in the blood that act as a nonspecific defense against bacteria. The proteins punch holes in the cell walls of bacteria, making them osmotically unstable.
Complement system
Complement can be activated through a ____________ pathway (which requires the binding of an antibody to a pathogen) or an ____________ pathway (which does not require antibodies).
- Classical pathway
- Alternative pathway
To protect against viruses, cells that have been infected with viruses produce ____________, proteins that prevent viral replication and dispersion.
Interferons
__________ are responsible for many “flu-like” symptoms that occur during viral infection, including malaise, tiredness, muscle soreness, and fever.
Interferons
_____________, a type of agranulocytes, reside within the tissue.
Macrophages
Macrophages derive from blood-borne ____________ and can become a resident population within a tissue (becoming a permanent, rather than transient, cell group in the tissue).
Monocytes
First, activated macrophages phagocytize the invader through ____________.
Endocytosis
Second, activated macrophages digest the invader using ___________.
Enzymes
Third, activated macrophages present little pieces of the invader (mostly peptides) to other cells using a protein called _________________ (_______).
Major histocompatibility complex (MHC)
The MHC binds to a pathogenic peptide (also called an ___________) and carries it to the cell surface, where it can be recognized by cells of the adaptive immune system.
Antigen
Macrophages release _________, chemical substances that stimulate inflammation and recruit additional immune cells to the area.
Cytokines
All nucleated cells in the body display _____________ molecules. Any protein produced within a cell can be loaded onto __________ and presented on the surface of the cell.
MHC class I
The MHC-1 pathway is often called the _____________ pathway because it binds antigens, such as unfamiliar (non self) proteins that come from inside the cell.
Endogenous pathway
___________ (MHC-I?/MHC-II?) molecules are mainly displayed by professional antigen-presenting cells like macrophages.
MHC class II
An _________ is a substance (usually a pathogenic protein) that can be targeted by an antibody.
Antigen
The MHC-II pathway is often called the ___________ pathway because the antigens originated outside the cell.
Exogenous pathway
___________ pathway for antigen presentation MHC-II exists only in professional antigen-presenting cells, like macrophages, dendritic cells, some B-cells, and some activated epithelial cells.
Exogenous pathway
This innate immune defender engulfs and consumes pathogens.
Macrophage
This innate immune cell releases histamine and other chemicals that promote inflammation.
Mast cell
Three cell types with tiny granules in their interiors - neutrophils, eosinophils, and basophils - participate in the inflammatory response.
Granulocytes
This cell represents antigens - fragments of protein or other molecules from pathogens or cancer cells - to adaptive immune cells, inducing them to attack bearers of the displayed antigens.
Dendritic cell
This cell destroys the body’s own cells that have become infected with pathogens; it also goes after cancer cells.
Natural killer cell
Macrophages and dendritic cells have special receptors known as ___________________ (______). ___________________ are able to recognize the category of the invader (bacterium, virus, fungus, or parasite).
Pattern recognition receptors (PRR)
The best-described pattern recognition receptors (PPR) are _________________ (_____).
Toll-like receptor (TLR)
______________ (______) cells, a type of nonspecific lymphocyte, are able to detect the downregulation of MHC and induce apoptosis in these virally infected cells. _______ cells also offer protection from the growth of cancer.
Natural killer (NK) cells
____________ are the most populous leukocyte in blood and are very short-lived. They are phagocytic, like macrophages, and target bacteria.
Neutrophils
The movement of an organism according to chemical stimuli.
Chemotaxis
Neutrophils can follow bacteria using ____________. The neutrophil senses products given off by bacteria, moving up the concentration gradient to the source.
Chemotaxis
Dead neutrophil collections are responsible for the formation of _________ during an infection.
Pus
______________ contain bright red-orange granules and are primarily involved in allergic reactions and invasive parasitic infections.
Eosinophils
Upon activation, eosinophils release large amounts of _______________, an inflammatory mediator.
Histamine
_____________ causes inflammation by inducing vasodilation and the movement of fluid and cells from the bloodstream into tissues.
Histamine
_______________ contain large purple granules and are involved in allergic responses. They are the least populous leukocyte in the bloodstream under normal conditions.
Basophils
____________ are closely related to basophils, but have smaller granules and exist in the tissues, mucosa, and epithelium.
Mast cells
Both _____________ and _____________ release large amounts of histamine in response to allergens, leading to inflammatory responses.
- Basophils
- Mast cells
____________ mature in the bone marrow and spleen.
B-cells
The name __________ is based of bursa of Fabricius, an organ found in bird.
B-cells
___________ are created in the bone marrow and mature in the thymus.
T-cells
______________, which involves the production of antibodies, may take as long as a week to become fully effective after initial infection.
Humoral immunity
___________ are lymphocytes that originate and mature in the bone marrow and are activated in the spleen and lymph nodes.
B-cells
Antigens stimulate this cell to divide and produce antibodies that neutralize invaders or tag them for killing.
B-cell
A ______________ destroys an infected cell in which it detects the presence of antigens.
Killer T-cell
___________ - such as helper and regulatory types - coordinate the immune response.
T-cells
Once bound to a specific antigens, antibodies may attract other leukocytes to phagocytize those antigens immediately. This is called ______________.
Opsonization
Antibodies may cause pathogens to clump together or _______________, forming large insoluble complexes that can be phagocytized.
Agglutinate
When antigen binds to antibodies on the surface of a mast cell, it causes _________________ (exocytosis of granule contents), releasing histamine and causing an inflammatory allergic reaction.
Degranulation
Antibodies are Y-shaped molecules that are made up of two identical ___________ chains and two identical ___________ chains.
- Heavy chains
- Light chains
___________ linkages and non-covalent interactions hold the heavy and light chains together.
Disulfide linkages
Each antibody has an antigen-binding region at the end of which is called the _____________ (domain, at the tips of the Y.
Variable region
Part of the reason it takes so long to initiate the antibody response is that each B-cell undergoes _______________ of its antigen-binding region, trying to find the best match for the antigen.
Hypermutation
Only those B-cells that can bind the antigen with high affinity survive, providing a mechanism for generating specificity called _____________.
Clonal selection
The ______________ (domain) of the antibody molecule is where cells such as natural killer cells, macrophages, monocytes, and eosinophils have receptors for, and that can initiate the complement cascade.
Constant region
Cells can change which isotope of antibody they produce when stimulated by specific cytokines in a process called __________________.
Isotope switching
_____________ (those that have not yet been exposed to an antigen) wait in the lymph nodes for their particular antigen to come along.
Naive B-cells
_____________ produce large amounts of antibodies, whereas ______________ stay in the lymph node, awaiting reexposure to the same antigen.
- Plasma cells
- Memory B cells
If the same microbe is ever encountered again, the memory cells rapidly proliferate and differentiate into ____________ to produce antibodies specific to that pathogen.
Plasma cells
The development of the lasting memory B cells is the basis of the efficacy of _______________.
Vaccination
______________ refers to allowing only the maturation of cells that can respond to the presentation of antigen on MHC (cells that cannot respond to MHC undergo apoptosis because they will not be able to respond in the periphery).
Positive selection
_______________ refers to causing apoptosis in cells that are self-reactive (activated by proteins produced by the organism itself).
Negative selection
The maturation of T-cells is facilitated by ______________, a peptide hormone secreted by thymic cells.
Thymosin
Upon exposuure to antigen, T-cells will undergo _______________ so that only those with the highest affinity for a given antigen proliferate.
Clonal selection
______________ (______) also called CD4+ T-cells, coordinate the immune response by secreting chemicals known as lymphokines.
Helper T-cells (Th)
______________ are capable of recruiting other immune cells (such as plasma cells, cytotoxic T-cells, and macrophages) and increasing their activity.
Helper T-cells
__________________ (_______) = Advanced human immunodeficiency virus (HIV) infection
Acquired immunodeficiency syndrome (AIDS)
_____________ respond to antigens presented on MHC-II molecules. Because MHC-II presents exogenous antigens, ______________ are most effective against bacterial, fungal, and parasitic infections.
CD4+ T-cells or Helper T-cells
________________ (________) are called CD8+ T-cells and are capable of directly killing virally infected cells by injecting toxic chemicals that promote apoptosis into the infected cells.
Cytotoxic T-cells (Tc or CTL, for cytotoxic T-lymphocytes)
__________ stands for cluster of differentiation and includes cell-surface markers that can be detected by the lab technique called flow cytometry.
CD
Because MHC-I presents endogenous antigens, ______________ are most effective against viral (and intracellular bacterial or fungal) infections.
CD8+ T-cells or Cytotoxic T-cells
_____________ or _____________ (_______) also express CD4, but can be differentiated from helper T-cells because they also express a protein called Foxp3.
Suppressor or Regulatory T-cells (T-reg)
Suppressor or regulatory T-cells can turn off self-reactive lymphocytes to prevent autoimmune diseases: this is termed ______________.
Self-tolerance
___________, which are similar to memory B-cells, lie in wait until the next exposure to the same antigen.
Memory T-cells
A bacterial infection is an (intracellular?/extracellular?)_____________ infection.
Extracellular infection
A viral infection is an (intracellular?/extracellular?)_____________ infection.
Intracellular infection
_________ cells release interferon gamma (IFN-gamma), which activates macrophages and increases their ability to kill bacteria.
Th1 (T-helper 1)
________ (type of T-cell?) cells help activate B-cells and are more common in parasitic infections.
Th2 (T-helper 2)
After the pathogen has been eliminated,___________ cells die, but memory B-cells and memory T-cells remain.
Plasma cells
_____________ help to tone down the immune response once infection has been adequately contained.
Suppressor/Regulatory T-cells (T-reg)
In a viral infection, the virally infected cell will begin to produce ______________, which reduce the permeability of nearby cells (decreasing the ability of the virus to infect these cells), reduce the rate of transcription and translation in these cells (decreasing the ability of the virus to multiply), and cause systemic symptoms (malaise, muscle aching, fever, and so on).
Interferons
______________ will recognize the MHC-I and antigen complex as foreign and will inject toxins into the cell to promote apoptosis.
CD8+ T-cells
in the event that the virus down regulates the production and presentation of MHC-I molecules, ______________ cells will recognize the absence of MHC-I and will accordingly cause apoptosis of these viral infected cells.
Natural killer cells
_____________ are the proteins and carbohydrates present on the surface of every cell of the body.
Self-antigens
When the immune system fails to make the distinction between self and antigen, it may attack cells expressing particular self-antigens, a condition known as _________________.
Autoimmunity
Allergies and autoimmunity are part of a family of immune reactions classified as ________________ reactions.
Hypersensitivity reactions
Most autoimmune diseases can be treated with a number of therapies; one common example is administration of _______________ (modified versions of cortisol), which have potent immunosuppressive qualities.
Glucocorticoids
In (active?/passive?)_____________ immunity, the immune system is stimulated to produce antibodies against a specific pathogen.
Active immunity
____________ immunity results from the transfer of antibodies to an individual. This immunity is transient because only the antibodies, and not the plasma cells that produce them, are given to the individual.
Passive immunity
The one-way vessels in the lymphatic system carry lymphatic fluid called ___________.
Lymph
The one-way vessels join together to form a large ______________ in the posterior chest, which then delivers the fluid into the left subclavian vein (near the heart).
Thoracic duct
______________ are small, bean-shaped structures along the lymphatic vessels.
Lymph nodes
Only when the lymphatics are overwhelmed does __________ occur - swelling due to fluid collecting in tissue.
Edema
____________, small lymphatic vessels, are located at the center of each villus in the small intestine.
Lacteals
Fats, packaged into _____________ by intestinal mucosal cells, enter the lacteal for transport.
Chylomicrons
Lymphatic fluid carrying many chylomicrons takes on a milky white appearance and is called _____________.
Chyle
_______________ are a place for antigen-presenting cells and lymphocytes to interact.
Lymph nodes
