Chapter 21 Immune System Mastering

innate external defenses -innate external defenses (surface barriers) are the first line of defense and include tears, mucus membranes, and the skin.

innate internal defenses -the macrophage recognizes many molecules found on pathogens that are not present on normal body cells.

the plasma B cells make antibodies in response to specific antigens.

also called an epitope, the antigenic determinant is the specific part of an antigen that the antibody or lymphocyte antigenic determinant receptor binds to. Part E

humoral immunity involves antibodies that can be transferred from one person to another.

cell-mediated immunity involves an intracellular pathogen such as a virus.

cytotoxic T cells attack cancer cells, since they are part of cell-mediated immunity.

Helper T cells activate B cells that are displaying antigen, causing clonal expansion. Helper T cells also activate cytotoxic T cells, which will search for and destroy infected host cells.

An activated B cell divides into cells that give rise to memory B cells and plasma cells.

Memory cells to that specific virus are stored in the lymph nodes for many years. When the student comes into contact with this specific Rhinovirus, these memory cells quickly divide and differentiate into antibody-producing plasma cells. The antibodies will prevent the virus from reaching an infectious titer (number that causes infection).

1. The Tc interacts with epitope presented by MHC-I on the dendritic cell 2. The helper T cell activates the Tc cell 3. The Tc recognizes the infected host cell 4. The Tc secretes perforin and granzyme, causing apoptosis

Recognition of infected host cell using its CD4 glycoprotein

1. Dendritic cell engulfs Rhinovirus 2. Endosome fuses with lysozome 3. Digestion of the Rhinovirus 4. Epitopes are attached to MHC-II 5. MHC-II plus the attached epitope move to the outside of the dendritic cell

BCR and TCR -Both of these molecules interact with epitopes. BCRs interact with epitopes on the whole pathogen. TRCs interact with processed epitopes when presented on MHC-II.

Activation of cytotoxic T cells by helper T cells

Clonal selection of B cells -B cells can still bind to antigen, which is the process of clonal selection. However, without a helper T cell, clonal expansion and antibody production will not occur.

Adaptive defenses include both humoral and cellular immunity.

T cells do not act as APCs. Quite the opposite, APCs present antigens to T cells.

Opsonization -Complement proteins stimulate inflammation, serve as opsonins to aid in the phagocytosis of targeted antigens, and facilitate cytolysis.

antigen-presenting cells

class II MHC proteins

class I MHC proteins are recognized by CD8 cells

all nucleated body cells bring pieces of endogenous proteins to the surface to display on the MHC protein.

CD8 cells become cytotoxic T cells.

T cells bearing CD8 receptors are activated by cells presenting endogenous antigens on class I MHC proteins.

Activated CD8 T cells become cytotoxic T cells.

disrupting the selective permeability of a bacteria's plasma membrane

It activates T helper cells by presenting antigen to them.

The complement cascade activates inflammation to destroy foreign substances in the body.

the membrane receptors on healthy cells -Interferon binds to membrane receptors in healthy cells and triggers a response inside the cell that leads to the production of chemicals that interfere with virus manufacture.

can kill cancer cells before the adaptive immune system is activated

Opsonins are needed to provide a gripping point on some cells that have capsules or other defenses against adherence by phagocytes.

Histamine is one of the products produced by mast cells to moderate inflammation. It is also released by basophils, which are similar to mast cells but reside in the blood.

diapedesis -The flattening of neutrophils and subsequent movement through the vessel wall is in response to cell adhesion molecules on endothelial cells.

Interferon is a small protein that can stimulate nearby healthy cells to defend themselves against viral infection.

have a great deal of rough endoplasmic reticulum reflecting the fact that they secrete a tremendous amount of protein (antibody)

Helper T cells are lymphocytes that organize the cellular and humoral immune response branches of the immune system.

can directly attack and kill other cells of the body Submit

function in the adaptive immune system activation

Any nucleated cell would present antigens to a CD8 cell.

A hapten is a foreign molecule that becomes immunogenic when combined with body proteins. -Haptens trigger adaptive defenses when combined with body proteins, making them appear foreign. Examples of haptens can be found in poison ivy, animal dander, and certain drugs.

Memory B cells trigger a secondary immune response, which is faster, more prolonged, and more effective than the first immune response.

When activated by the presence of antigens, B lymphocytes proliferate into plasma cells. Plasma cells generate antigen-specific antibodies.

They bind to the pathogen and secrete chemicals that induce apoptosis.

The skin is the first innate barrier that works to prevent entry of any pathogens into the body.

Mucus contains macrophages that attack invading pathogens. -Mucus itself does not typically contain macrophages.

The third line of defense responds to antigens on the pathogen.

Humoral immunity refers to the presence of specific antibodies in the body fluids.

The innate defenses of the body apply strictly to external pathogens, while adaptive defenses apply strictly to internal pathogens.

Natural killer cells bind to target cells and secrete perforins and granzymes that degrade the target cell membrane. They also bind to membrane receptors that induce apoptosis.

Bruising is a sign of internal hemorrhaging and injury, but bruising is not a typical part of the inflammatory response.

Activated complement proteins help amplify the immune response and lyse bacterial cells. These proteins also enhance the adaptive defenses.