Ch. 8: The Immune System

Question 1

Divisions of Immune Sys

Answer 1

Innate and Adaptive Immunity

Question 2

Innate immunity or Nonspecific immunity

Answer 2

Composed of defenses that are always active, but that cannot target a specific invader and cannot maintain immunologic memory.

Question 3

Adaptive immunity or Specific immunity

Answer 3

Composed of defenses that take time to activate, but that target a specific invader and can maintain immunologic memory

Question 4

Bone marrow

Answer 4

Immune cells come from the bone marrow

Question 5

Spleen and Lymph Nodes

Answer 5

Sites where immune responses can be mounted, and in which B-cells are activated

Question 6

Thymus

Answer 6

Site of T-cell maturation

Question 7

Gut-associated lymphoid tissue (GALT)

Answer 7

Includes tonsils and adenoids

Question 8

Leukocytes

Answer 8

White blood cells, are involved in immune defenses

Question 9

Skin

Answer 9

Acts as a physical barrier and secretes antimicrobial compounds like defensins.

Question 10

Mucus

Answer 10

On mucous membranes traps pathogens; in the respiratory system, the mucus is propelled upward by cilia and can be swallowed or expelled

Question 11

Lysozyme

Answer 11

Tears and Saliva contain lysozyme an antibacterial compound

Question 12

Stomach

Answer 12

The stomach produces acid, killing most pathogens; Colonization of the gut helps prevent overgrowth by pathogenic bacteria through competition

Question 13

Complement system

Answer 13

Can punch holes in the cell walls of bacteria, making them osmotically unstable

Question 14

Interferons

Answer 14

Given off by virally infected cells and help prevent viral replication and dispersion to nearby cells

Question 15

Macrophages

Answer 15

Ingest pathogens and present them on major histocompatibility complex (MHC) molecules. They also secrete cytokines

Question 16

MHC class I (MHC-I)

Answer 16

Present in all nucleated cells and displays endogenous antigen (proteins from within the cell) to cytotoxic T-cells

Question 17

MHC class II (MHC-II)

Answer 17

Present in professional antigen-presenting cells (macrophages, dendritic cells, some B-cells, and certain activated epithelial cells) and displays exogenous antigen (proteins from outside the cell) to helper T-cells (CD4+ cells)

Question 18

Dendritic Cells

Answer 18

Antigen-presenting cells in the skin

Question 19

Natural killer cells

Answer 19

Attack cells presenting MHC molecules, including virally infected cells and cancer cells

Question 20

Granulocytes

Answer 20

Include neutrophils, eosinophils, and basophils

Question 21

Neutrophils

Answer 21

Ingest bacteria, particularly opsonized bacteria (those marked w antibodies). They can follow bacteria using chemotaxis

Question 22

Eosinophils

Answer 22

Used in allergic reactions and invasive parasitic infections. They release histamine, causing an inflammatory response.

Question 23

Basophils

Answer 23

Used in allergic reactions

Question 24

Mast Cells

Answer 24

Related to basophils, found in the skin

Question 25

Humoral immunity

Answer 25

Centered on antibody production by plasma cells, which are activated B-cells

Question 26

Antibodies

Answer 26

Target a particular antigen. Containm 2 heavy chains and 2 light chains. They have a constant region and a variable region; the tip of the variable region is the antigen binding region

Question 27

Hypermutation

Answer 27

When activated, the antigen-binding region undergoes hypermutation to improve the specificity of the antibody produced. Cells may be given signals to switch isotypes of antibody (IgM, IgD, IgG, IgE, IgA)

Question 28

Opsonize and Agglutination by Antibodies

Answer 28

Circulating antibodies can opsonize pathogens (mark them for destruction), cause agglutination (clumping) into insoluble complexes that are ingested by phagocytes, or neutralize pathogens

Question 29

Cell surface antibodies can

Answer 29

Activate immune cells or mediate allergic reactions

Question 30

Memory B-cells

Answer 30

Lie in wait for a second exposure to a pathogen and can then mount a more rapid and vigorous immune response (secondary response)

Question 31

Cell-mediated (cytotoxic) immunity

Answer 31

Centered on the functions of T-cells

Question 32

T-cells undergo maturation in the thymus through

Answer 32

Positive selection: only selecting for T-cells that can react to antigen presented on MHC) Negative selection: causing apoptosis in self-reactive T-cells

Question 33

Thymosin

Answer 33

Promotes T-cell development

Question 34

Helper T-cells

Answer 34

Aka Th or CD4+; respond to antigen on MHC-II and coordinate the rest of the immune system, secreting lymphokines to activate various arms of immune defense

Question 35

Th1 cells

Answer 35

Secrete interferon gamma which activates macrophages

Question 36

Th2 cells

Answer 36

Activate B-cells, primarily in parasitic infections

Question 37

Cytotoxic T-cells (Tc, CTL, or CD8+)

Answer 37

respond to antigen on MHC-I and kill virally infected cells

Question 38

Suppressor (regulatory) T-cells (Treg)

Answer 38

tone down the immune response after an infection and promote self-tolerance

Question 39

Memory T-cells

Answer 39

Serve a similar function to memory B-cells

Question 40

Autoimmune conditions

Answer 40

A self-antigen is recognized as foreign and the immune sys attacks normal cells

Question 41

Allergic reactions

Answer 41

Nonthreatening exposures incite an inflammatory response

Question 42

Immunization

Answer 42

Method of inducing active immunity (activation of B-cells that produce antibodies to an antigen) prior to exposure to a particular pathogen

Question 43

Passive immunity

Answer 43

Transfer of antibodies to an individual

Question 44

Lymphatic system

Answer 44

Circulatory sys that consists of one-way vessels with intermittent lymph nodes

Question 45

Thoracic duct

Answer 45

In the posterior chest, connects lymphatic sys to the cardiovascular sys

Question 46

Chylomicrons

Answer 46

Lymphatic sys equalizes fluid distribution, transports fats and fat soluble compounds in chylomicrons, and provides sites for mounting immune responses