The ___ has evolved in multicellular organisms to defend against bacteria, viruses, and other foreign substances.
immune system
Although the immune response normally is protective, it also can produce undesirable effects such as when the response is excessive, as in ______, or when it recognizes self-tissue as foreign, as in ____ disease.
allergies, autoimmune
As the first line of defense, ____ immunity consists of the physical, chemical, molecular, and cellular defenses.
innate
_____ immunity is the second major immune defense.
Adaptive
Substances that elicit adaptive immune responses are called ______.
antigens
_____ immunity, generated by B lymphocytes, is mediated by molecules called antibodies and is the principal defense against extracellular microbes and toxins.
Humoral
____ immunity is mediated by specific T lymphocytes and defends against intracellular microbes such as viruses
Cell-mediated
Dendritic cells and ____ function as antigen-presenting cells for adaptive immunity.
macrophages
The key cells of innate immunity are _____, _____, and natural killer cells.
neutrophils, macrophages
____ are the early responding cells of innate immunity.
Neutrophils
During an inflammation response, the monocyte leaves the blood vessel, transforms into a tissue _____, and phagocytosis bacteria, damaged cells, and tissue debris.
macrophage
____ cells and _____ cells are the only cells in the body capable of specifically recognizing different antigenic determinants of microbial agents and other pathogens.
B, T
____ are part of the innate immune system, and may be the first line of defense against viral infections.
Natural killer cells
_____ cells are specialized, bone marrow-derived leukocytes found in lymphoid tissue that are important intermediates between the innate and adaptive immune systems.
Dendritic
___ are cytokines that stimulate the migration and activation of immune and inflammatory cells.
Chemokines
Cytokines that stimulate bone marrow pluripotent stem and progenitor or precursor cells to produce large numbers of platelets, erythrocytes, lymphocytes, neutrophils, monocytes, eosinophils, basophils, and dendritic cells are known as _____.
colony-stimulating factors
The mucous membrane linings of the gastrointestinal, respiratory, and urogenital tracts are protected by sheets of tightly packed ____ cells that block the entry of microbes.
epithelial
The binding of ____ to the pattern recognition receptors on leukocytes initiates the signaling events that lead to innate immunity and tissue changes associated with acute inflammation.
pathogens
____ is the coating of a microorganism with soluble molecules that tag the microorganisms for more efficient recognition by phagocytes.
Opsonization
____ are substances foreign to the host that can stimulate an immune response.
Antigens
Antibodies comprise a class of proteins called _____.
Immunoglobulins
_____ immunity depends on maturation of B lymphocytes into plasma cells, which produce and secrete antibodies.
Humoral
The ____ serves as a master regulator for the immune system.
CD4+ helper T cell (TH)
_____ T cells suppress immune responses by inhibiting the proliferation of other potentially harmful self-reactive lymphocytes.
Regulatory
The central lymphoid organs, the ____ and the _____, provide the environment for immune cell production and maturation.
bone marrow, thymus
The white pulp layer of the _____ contains concentrated areas of B and T lymphocytes permeated by macrophages and dendritic cells.
spleen
Mucins
Traps and washes away potential invaders
Lysozyme
Hydrolytic enzymes capable of cleaving the walls of bacterial cell
Epithelial barrier
The physical barrier of skin to infection
Defensins
Small cationic peptides found in the stomach
Collectins
Surfactant proteins in respiratory track
Cilia
Epithelial protrusion that moves mucus to throat
Toll-like receptors
Pathogen-associated molecular pattern receptors
Opsonins
Renders bacteria and other cells susceptible to phagocytosis
NF-K?
Regulates the production of cytokines and adhesion molecules
Interferons
Disrupts virus infections
Epitopes
Immunologically active sites on antigen
CD4+
Type of T helper cell
Perforins
Pore-forming molecules
Cell-mediated immunity
Dependent on T cells
Antigen presentation
Processing a complex antigen into epitopes and then displaying the foreign and self peptides on their membranes
Antibody-mediated immunity
Dependent on B cells
Major histocompatibility complex
Self-recognition proteins
Haptens
Combine with larger protein molecules and serve as antigens
CD8+
Cytotoxic T cells
Tolerance
Ability of the immune system to be nonreactive to self-antigens
How do the cells of the immune system communicate with each other?
Although cells of both the innate and adaptive immune systems communicate critical information by cell-to-cell contact, many interactions and effector responses depend on the secretion of short-acting soluble molecules called cytokines. One type of cytoki
What is the innate immune system and what is its function?
The innate immune system consists of epithelial barriers, phagocytic cells (mainly neutrophils and macrophages), natural killer (NK) cells, and several plasma proteins including those of the complement system. These mechanisms are present in the body befo
What is the general function of neutrophils and macrophages in the inflammatory response?
These phagocytic cells recruited during an inflammatory response to recognize and kill infectious invaders. The early-responding innate immune cell is the neutrophil, followed shortly by the more efficient, multifunctional macrophage. They are activated t
What are the methods of initiating the complement system and what are the results of activation?
There are three pathways for recognizing microorganisms that result in activation of the complement system: the classical, the lectin, and the alternative pathway. The reactions of the complement systems are divided into three phases: (1) initiation or ac
What is the function of MHC proteins, and how are they classified?
The major histocompatibility complex (MHC) molecules involved in self-recognition and cell-to-cell communication fall into two classes Class I and class II. Class I MHC molecules are cell surface glycoproteins that interact with the antigen receptor-forei
Explain how a macrophage participates in antigen presentation.
Macrophages are key members of the mononuclear phagocytic system that engulf and digest microbes and other foreign substance. The monocytes migrate from the blood to various tissues where they mature into the major tissue phagocyte, the macrophages. As th
How many classes of antibody are there? Give a brief definition of unction for each one.
The immunoglobulins have been divided into five classes: IgG, IgA, IgM, IgD, and IgE.
1. IgG protects against bacteria, toxins, and viruses in body fluids and activates the complement system.
2. IgA is a primary defense against local infections in mucosal
Compare and contrast active versus passive immunity.
Active immunity is acquired through immunization or actually having a disease. It is active as it depends on a response to the antigen by the person's immune system. Because of memory, the immune system usually is able to react within hours to subsequent
Natural killer cells are specialized lymphocytes that are one of the major parts of which immunity?
Innate immunity. The major components of innate immunity are the skin and mucous membranes; phagocytic cells (mainly neutrophils and macrophages); specialized lymphocytes called natural killer cells; and several plasma proteins, including the proteins of
Both innate and adaptive immunity have cells that produce cytokines. Cytokines mediate the actions of many cells in both innate and adaptive immunity. How are the actions of cytokines described?
Pleiotropic and redundant. The actions of cytokines are often pleiotropic and redundant. Cytokines are not described as rapid and self-limiting, or cell-specific and targeted, or dendritic and morphologic.
Stem cells in the bone marrow produce T lymphocytes or T cells, and release them into the vascular system. The T cells then migrate where to mature?
Thymus. The T lymphocytes (T cells) are generated from stem cells in the bone marrow and complete their maturation in the thymus and functions in the peripheral tissues to produce cell-mediated immunity, as well as aiding antibody production.
Cell-mediated immunity is involved in resistance to infectious diseases caused by bacteria and some viruses. It is also involved in cell-mediate hypersensitivity reactions. Which of these does not cause a cell-mediated hypersensitivity reaction?
Blood transfusion. Activation of macrophages ensures enhanced phagocytic, metabolic, and enzymatic potential, resulting in more efficient destruction of infected cells. This type of defense is important against intracellular pathogens such as Mycobacteriu
Passive immunity is immunity that is transferred from another source and lasts only weeks to months. What is an example of passive immunity?
An injection of gamma-globulin. Passive immunity also can be artificially provided by the transfer of antibodies produced by other people or animals. Some protection against infection of hyperimmune serum, which contains high concentrations of antibodies
An essential property of the immune system is self-regulation. An immune response that is not adequate can lead to immunodeficiency, while an immune response that is excessive can lead to conditions from allergic responses all the way to autoimmune diseas
Huntington disease. Self-regulation is an essential property of the immune system. An inadequate immune response may lead to immunodeficiency, but an inappropriate or excessive response may lead to conditions varying from allergic reactions to autoimmune
One of the self-regulatory actions of the immune system is to identify self-antigens and be nonreactive to them. What is this ability of the immune system defined as?
Tolerance. The term tolerance is used to define the ability of the immune system to be nonreactive to self-antigens while producing immunity to foreign agents. All other responses have nothing to do with the recognition and tolerance of self-antigens.
The laboratory finds IgA in a sample of cord blood from a newborn infant. This finding is important because it signifies what?
Fetal reaction to exposure to an intrauterine infection. Cord blood does not normally contain IgM or IgA. If present, these antibodies are of fetal origin and represent exposure to intrauterine infection.
The daughter of a 79-year old woman asks the nurse why her mother gets so many infections. The daughter states, "My mother has always been healthy but now she has pneumonia. Last month she got cellulitis from a bug bite she scratched. The month before tha
The daughter of a 79-year old woman asks the nurse why her mother gets so many infections. The daughter states, "My mother has always been healthy but now she has pneumonia. Last month she got cellulitis from a bug bite she scratched. The month before tha
The results of recent research suggests that a key role in the origin of some diseases is played by inflammation. Which of these diseases is it thought that inflammation has a role in its beginnings?
Rheumatoid arthritis. Among the functions of the innate immune system is induction of a complex cascade of events known as the inflammatory response. Recent evidence suggests that inflammation plays a key role in pathogenesis of a number of disorders such
____, or Immunogens, are substances foreign to the host that can stimulate an immune response.
Antigens, or Immunogens, are substances foreign to the host that can stimulate an immune response.
IgG
Protects against bacteria, toxins, and viruses in body fluids and activates the complement system.
IgA
A primary defense against local infections in mucosal tissues
IgM
Is the first circulating immunoglobulin to appear in response to an antigen and is the first antibody type made by a newborn.
IgD
Serves as an antigen receptor for initiating the differentiation of B cells
IgE
Involved in inflammation, allergic responses, and combating parasitic infections
The mucous membrane linings of the gastrointestinal, respiratory ,and urogenital tracts are protected by sheets of tightly packed ____ cells that block the entry of microbes and destroy them by secreting antimicrobial enzymes, proteins, and peptides.
The mucous membrane linings of the gastrointestinal, respiratory ,and urogenital tracts are protected by sheets of tightly packed epithelial cells that block the entry of microbes and destroy them by secreting antimicrobial enzymes, proteins, and peptides
In both the innate and the adaptive immune systems, cells communicate information about invading organisms by the secretion of chemical mediators. What are these mediators?
Chemokines and Colony-stimulating factors. While cells of both the innate and adaptive immune systems communicate critical information about the invading microbe or pathogen by cell-to-cell contact, many interactions and effector responses depend on the s
There are many cells that make up the passive and adaptive immune systems. Which cells are responsible for the specificity and memory of adaptive immunity?
T lymphocytes and B lymphocytes. The T and B lymphocytes are the only cells in the body capable of specifically recognizing different antigenic determinants of microbial agents and other pathogens, and therefore responsible for two defining characteristic