Microbiology Unit 4 (Part 1)

The major histocompatibility complex is

A set of genes that code for MHC glycoproteins

Helper T Cells

Activate B cells and other T cells

Gamma-delta T cells ________. Are considered a bridge between nonspecific and specific immune responses Have T cell-receptors that target a wide range of antigens Can bind to, and become activated by PAMPs Differentiate into memory cells All of the choices are true.

All of the choices are true.

When an antibody is covering a foreign microorganism, complement may be activated via the pathway

Classical

Antitoxins...

Confer passive immunity.

Keratin is an important aspect of nonspecific defense because it

Creates a physical barrier against pathogens

After secreting antibodies during an immune response, plasma cells then differentiate into memory cells. True or False

False

The third line of defense can be summarized in four stages; I—antigen binding to T helper cells, II—antigen binding to B cells, III—phagocytosis of antigen by B and T lymphocytes, IV—killing of antigen. True or False

False

Which is incorrect about the Fc region of an immunoglobulin? Contains an effector molecule that can bind to cells such as macrophages and mast cells Forms the antigen binding sites Determines the class to which the immunoglobulin belongs Is called the crystallizable fragment

Forms the antigen binding sites

The monomer subunit of immunoglobulin molecules has all the following except: Two identical light polypeptide chains. A variable and constant region on each polypeptide chain. Disulfide bonds between polypeptide chains. Two identical heavy polypeptide chains. Four antigen binding cites.

Four antigen binding cites

Neutrophils, Eosinophils, and Basophils are called _ because they have prominent cytoplasmic inclusions that, in a stained blood smear, appear with identifying, characteristic colors.

Granulocytes

Properties of effective antigens include all the following, except A. foreign to the immune system. B. molecular complexity. C. large molecules with a minimum molecular weight of 1,000. D. large polymers made up of repeating subunits. E. cells or large, complex molecules.

Have large polymers made up of repeating subunits

Each of the following are benefits of fever except it_. increases phagocytosis stimulates hematopoiesis increases the availability of iron increases metabolism reduces the ability of temperature-sensitive organisms to multiply

Increases the availability of iron.

Which of the following fluid compartments is not a partner in immune faction? Extracellular fluid Lymphatic system Bloodstream Intracellular fluid

Intracellular fluid

When monocytes migrate from the blood out to the tissues they are transformed by inflammatory mediators to develop into_.

Macrophages

All of the following are early events of inflammation except_. capillaries become more permeable resulting in edema exudate and pus can accumulate macrophages appear first and begin phagocytosis brief vasoconstriction is followed by vasodilation chemical mediators and cytokines are released

Macrophages appear first and begin phagocytosis

Which of the following is in the correct order from greatest to least phagocytic activity? Macrophages, neutrophils, eosinophils Macrophages, eosinophils, neutrophils Neutrophils, macrophages, eosinophils Eosinophils, macrophages, neutrophils Neutrophils, eosinophils, macrophages

Macrophages, Neutrophils, Eosinophils

Immune system cells differentiate between self and foreign cells by their

Markers

Which white blood cells comprise 3% to 7% of circulating WBCs, are phagocytic, and can migrate out into body tissues to differentiate into macrophages?

Monocytes

Which if the following is incorrect about complement? Acts in a cascade reaction Involves a classical pathway Only appears in the blood during a response to a pathogen Involves an alternate pathway Is composed of at least 20 blood proteins

Only appears in the blood during a response to a pathogen

During what process are hypochlorite and hydrogen peroxide produced to destroy bacteria and inhibit viral replication?

Phagocytosis

Each of the following in the migration of the white blood cells except_. chemotaxis diapedesis motility vasodilation phagocytosis

Phagocytosis

Which of the following is mismatched? Interferon alpha and beta—inhibits viral replication Prostaglandins—activate eosinophils and B cells Tumor necrosis factor—increases chemotaxis and phagocytosis Serotonin—causes smooth muscle contraction Interleukin-2—stimulates T-cell mitosis and B-cell antibody production

Prostaglandins - activate eosinophils and B cells

Which of the following is incorrect about inflammation? It can last hours to years. Pyrogens cause vasodilation and increased capillary permeability. Serotonin causes smooth muscle contraction. Fever could be beneficial to inhibiting the pathogen. Basophils and mast cells release histamine.

Pyrogens cause vasodialation and increased capillary permeability.

MHC molecules are found on each of the following cells except: Islet of langerhans cells Leukocytes Red blood cells Eosinophils Epithelial cells

Red blood cells

Which of the following is not a property of B cells? Require antigen presented with MHC proteins Receptors called immunoglobins Low numbers circulating in the blood Mature in the bone marrow Produce plasma cells and memory cells

Require antigen presented with MHC proteins

Cytotoxic T cells...

Secrete granzymes and perforins that damage target cells.

Cytokines mediate a variety of processes in the immune system, for example, _ encourages inflammatory responses and _ suppresses the action of immune cells.

TNF-β; IL- 10

In addition to dendritic cells and macrophages, B cells can also act as antigen-presenting cells. This occurs when ________. The antigen binds to the B cell and after processing, it is presented to the dendritic cells and macrophages The B cell engulfs the antigen and presents it to the T helper cell The B cell engulfs the antigen and presents it to the T cytotoxic cell The antigen is a molecule with a simple, repeating structure and evokes an immune response as a T-cell-independent antigen

The antigen is a molecule with a simple, repeating structure and evokes an immune response as a T-cell-independent antigen.

The human microbiome is considered an important component of the first line of defense. Which statement adequately reflects tits role as a defensive barrier?

The human microbiota competes with pathogens for space and nutrients limiting their ability to cause infection, and trains the immune system to recognize antigens.

Inflammation, fever, phagocytosis, and antimicrobial molecules are considered innate because

They are not antigen- specific: they contribute to host defense regardless of the source of activation.

Activation of B cells occurs when antigen binds to B-cell surface immunoglobulin receptors. True of False

True

Antibody molecules circulate in lymph, blood, and tissue fluids. True of False

True

During inflammation, a high neutrophil count is a common sign of bacterial infection. T/F

True

One plasma cell will secrete antibodies of various classes but the antibodies will all have the same specificity. True or False

True

Overuse of disinfectants and antiseptics, as well as antibiotics, can result in inflammatory diseases stemming from an inadequate microbiome. T/F

True

The diversity and specificity of the lymphocyte repertoire against any potential antigen it may encounter is due to the rearrangement of gene segments that code for the antigen receptors. True or False

True

The second line of defense is a series of systems that involves both cells and chemicals working together. T/F

True

Class II MHC genes code for

receptors located primarily on macrophages and B cells.

Plasma cells

secrete antibodies