Chapter 16: Immune System

What is the secondary immune response?

If the same antigen is encountered again, more #'s memory cells can count (act) more rapidly

How are antigens identified?

Receptors on lymphocyte surfaces, they are able to recognize foreign antigens

What do cytotoxic T cells do? How do they do it?

Recognize and rliminate tumor cells and virus infected cells by release of perforin and other means Continually monitor the body's own cells bind to the surfaces of the antigen-bearing cells, then release perforin

An immune response is based on? Who carries out the immune responses?

The ability to distinguished molecules that are part of the body from those that are foreign Lymphocytes and macrophages

What is species resistance?

The fact that a given kind of organism or species develops diseases that are unique to it species might be resistant to disease that affects others if fro some reason it fails to provide the right temperature and chemical environment the pathogen needs

T cell activation require what?

The presence of of an antigen-bearing cell (macrophage or B cell) that has already encounter the antigen

What causes the redness of inflammation?

The result of dilated blood vessels

What causes the swelling of inflammation?

The result of increased capillary/venule permeability

What causes the heat of inflammation?

The result of the entry of blood from deeper parts of the body

What causes the the pain of inflammation?

The result of the stimulation of pain receptors

What is the primary response? What does it produce?

When B or T cells become activated for the first time. First response when a person is first exposed to an antigen Some B cells produce memory cells

When does an immune complex reaction occur? What is autoimmunity?

When antigen-antibody complexes cannot be cleared from the body - leads to autoimmunity The loss of the ability to tolerate self-antigens

When do antibody-dependent cytotoxic reactions take place?

When blood transfusions are mismatched

What are pathogens?

disease causing agents, can produce infections within the body

How does the cellular immune response take place?

cell to cell contact between T-cell and antigen cell ex: T cells attack foreign matter, antigen-bearing calle,s (bacteria) by direct cell to cell contact, providing cell-meditated immunity - it does not involve antibodies, but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.

What is this antibody-mediated immune response called?

humoral immune response

What is a polyclonal response?

the production of several different antibodies against one pathogen, it happens because pathogens often have different antigens on their surfaces

What does inflammation do? What cells do normally migrate to the areas of inflammation?

It causes WBC to invade the affected area, it also increases fluid and fibrin Fibroclasts appear and it is an active site of phagocytosis, well cell replacement takes place Neutrohils and monocytes

What is an allergic reaction?

An immune response against a non-harmful substance hypersensitivity reactions that are excessive immune responses that may lead to tissue damage

What happens in direct act?

Antibodies combine with antigens and cause them to clump (agglutination) Phagocytic cells can engulf antigen bearing pathogens easier when they are clumped together Antibodies can also cover toxic portions of antigens, neutralizing their affects

What are chemical barriers? What are some examples?

Body fluids that contain enzymes or antimicrobial substances gastric juice, interferons, defensins lysozyme (tears) also kill pathogens

How is competent activated? What is its function?

By the binding of certain antibodies to antigens Opsonization, chemotaxis,, cell lysis, and inflammation

What are the four transplant types?

1) Isograft - identical twin 2) autograft - self 3) allograft - same species 40 xenograft - different species

What are the three ways antibodies react to antigens?

1) directly attack antigens (agglutination, precipitation, and neutralization of antigens) 2) Activate complement (can produce opsonization, chemotaxsis, inflammation, or lysis in target cells or antigens 3) via stimulation of changes in areas that prevent pathogen spreading

What happens in the Humral Immune Response What happens when a B cell becomes activated? What happens to some cloned B cells? What do antibodies do? Does the body fluids carry antibodies?

1. B cells become activated when an antigen binds to its membrane bound receptor. B cells start to divide - Helper T cells help B cells by releasing cytokines that stimulate B cell proliferation which leads to cloning they differentiate further into plasma cells, which leads to secretion of large globular proteins called antibodies or immunoglobulins they combine with antigen on the pathogen and react against it Yes, can react in many ways, to destroy specific antigens or antigen bearing particles

How many types of immunoglobulins are there? Which are the most common that make up the bulk of circulating antibodies?

5, IgG, IgA, IgM, IgD, and IgE IgG, IgA, IgM

What is an abnormal cell?

A cell that is infected by viruses and cancer cells.

What is complement? What does it do when activated?

A group of proteins in plasma and other body fluids that interact in a series of reactions it stimulates inflammation, attracts phagocytes, and enhances phagocytosis

What is an anaphylatic shock? What causes this?

A severe form of immediate-reaction allergy that may lead to death allergy mediators sometimes flood the body

What is a hapten? What are examples?

A small molecule that must bind to a larger molecule to elicit an immune response Chemicals found in drugs, household cleaners, dust, and skins of certain animals

What is inflammation? What does it produce?

A tissue response to a pathogen Redness, swelling, heat, and pain

What are perforins? What do they do?

Cytolytic substances that are secreted by NK cells Cause the cell membrane to disintegrate, killing the infected cell

What do mast cells release during allergic reactions?

Histamine and serotonin

What is an artificially active immunity?

Immunity that develops when a person is given a vaccine

What is naturally acquired active immunity?

Immunity that develops when a person is naturally exposed to an antigen

What is an artificially acquired passive immunity?

Immunity that occurs when a person is injected with antibodies or anti-toxins

What is a naturally acquired passive immunity?

Immunity that occurs when antibodies are passed across the placenta or through the mothers milk

Where is IgA found? What is its function?

In exocrine gland secretions to defend against bacteria, and viruses

Where is IgD found? What is its function?

In the cell membranes of B cells To act as receptors for B cells

Where is IgG found? What is its function?

It is found in the plasma To defend against bacteria, viruses and toxins, activates complement

Where is IgM found? What is its function?

It is found in the plasma To react with antigens occurring on red blood cells and to activate complement

What is immunity?

It is the resistance to particular pathogens or their toxins It is the response mounted by the body against specific, recognized foreign antigens

Where is IgE found? What is its function?

Located in exocrine gland secretions To promote inflammation and allergic reactions

What is an antigen (agglutinogen)?

Molecules that can elicit an immune system

What are the two types of defenses against pathogens?

Nonspecific (guard against any pathogen) and specific (respond to a specific threat)

B cells become what? What do they produce?

Plasma cells Antibodies

What releases lymphocytes? What percentage become T lymphocytes? What about the rest? What happens if an undifferentiated lymphocyte reaches the thymus gland? Where do B cells mature? Where are B and T cells found?

Red bone marrow 70-80% Become B cells It becomes a T cell In the bone marrow They are abundant in the lymph nodes, spleen, bone marrow, and intestinal lining

What do colony stimulating factors do? What do interferons do? What do interleukins do? What do tumor necrosis factor do?

Stimulate bone marrow to produce lymphocytes Block viral replication, stimulate macrophages to enguld viruses; stimulate B cells to produce antibodies, attack cancer cells control lymphocyte differentiation and growth stops tumor growth, releases growth factor, causes fever that accompanies,

What happens when someone has a fever? How does temperature increase impact the phagocytic cells?

There is a reduce amount of Fe in the blood There is also a less nutrients available They attack with "great vigor"

What are interferons? What is its function? Who produces it? What does it interfere with? What else does it do?

They are produced by lymphocytes and fibroblasts Stimulation of phgagocytosis and prevention of viral infections the virus-infected cells viral transcription It may induce near by cellls to produce anti-viral enzymes

What do natural killer cells do? Are there a lot of NKs?

They protect the body against cancer and viruses Responsible for recognizing and destroying abnormal cells when they appear No, they are a small portion of lymphocytes

What is the purpose of the mechanical barriers? What are some examples?

To prevent the entrance of some infections agents Skin, mucous membranes, and hair It is the first line of defense

What is the purpose of phagocytosis? What are the phagocytic cells that are spread out throughout the body (mononunclear phagocytic system) How do these cells leave the bloodstream? Does phagocytosis also remove foreign particles from the lymph?

To remove foreign particles Neutrophils (smallest), monocytes(largest), and macrophages via diapedesis Yes

What produces defensins?

WBC To make holes in bacterial cell wall and to destroy certain pathogens

Antibody Molecules Are antibodies soluble? What is an antibody compose of? How many types of chains? How are the 5 major types of antibodies distinguished? What does the variable region do?

Yes, they are globular protein Four chains of amino acids that are link together 2 types of chains - light chains are identical and contain half the number of amino acids as heavy chains - heavy chains are identical and contain twice the number of amino acids as light chains By the particular kind of heavy chain It is the part of the antibody that contains variable sequences of amino acids specialized to react to the shape of a specific antigen molecule

What is perforin?

a protein that cuts porelike openings, destroying the cells

What is the purpose of a memory T cell?

respond to an antigen during a future exposure and to differentiate immediately into active cytotoxic T dells they provide no delay response to any future expose of same antigen

What do Helper T cells do?

stimulate B cells to produce antibodies specific for the displayed antigen and to secrete cytokines Activation must first encounter a macrophage displaying the antigen

Who produces cytokines? What do they do? What are the four types of cytokines

the T cells they enhance cellular response to antigens - may also secrete toxins that kill target cells - may produce growth-inhibiting factors - may also make interferon to interfere with viruses and tumor cells interleukins, colony stimulating factors, interferons, and tumor nercrosis factor

What is a delayed-reaction allergy?

the result from repeated exposure to substances that cause inflammatory reactions in the skin occurs when a person is repeatedly exposed to an allergen and the allergic reaction occurs 48 hours after exposure of antigen

What happens to the other activated B cells? What is their purpose?

they differentiate further into memory cells to respond rapidly to future exposures to a specific antigen