Biology Chapter 8: The Immune System

Question 1

Innate immunity

Answer 1

composed of defenses that are always active but that cannot target a specific invader and cannot maintain immunologic memory, also called nonspecific immunity.

Question 2

Adaptive immunity

Answer 2

Composed of defenses that take time to activate, but that target a specific invader and can maintain immunologic memory; also called specific immunity.

Question 3

Where do immune cells come from?

Answer 3

Bone marrow

Question 4

Where are B-cells activated

Answer 4

Spleen and lymph nodes (immune responses can be mounted here)

Question 5

Thymus

Answer 5

Site of T-cell maturation

Question 6

Gut-associated lymphoid tissue

Answer 6

includes tonsils and adenoids

Question 7

Immune role of skin

Answer 7

acts as a physical barrier and secretes antimicrobial compounds like defensins

Question 8

Immune role of mucus

Answer 8

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

Question 9

Immune role of tears and saliva

Answer 9

contain lysozome, an antibacterial compound

Question 10

Immune role of stomach

Answer 10

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

Question 11

Immune role of the complement system

Answer 11

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

Question 12

Immune role of inferons

Answer 12

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

Question 13

Macrophages

Answer 13

ingest pathogens and present them on major histocompatibility complex molecules. They also secrete cytokines.

Question 14

MHC class I

Answer 14

present in all nucleated cells and displays endogenous antigen (proteins from within the cell) to cytotoxic T-cells (CD8+ cells)

Question 15

MHC class II

Answer 15

present in professional antigen-resenting cells (macrophages, dentritic cells, some B-cells & certain activated epithelial cells) and displays exogenous antigen (proteins from outside the cell) to helper T-cells (CD4+ cells)

Question 16

Dendritic cells

Answer 16

antigen, presenting cells in the skin.

Question 17

Natural killer cells

Answer 17

attack cells not presenting MHC molecules. Including virally infected cells and cancer cells.

Question 18

Granulocytes

Answer 18

include neutrophils, eosinophils and basophils

Question 19

Neutrophils

Answer 19

ingest bacteria, particularly opsonized bacteria (those marked with antibodies) They can follow bacteria using chemotaxis

Question 20

Eosinophils

Answer 20

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

Question 21

Basophils

Answer 21

used in allergic reactions. Mast cells are related cells found in the skin.

Question 22

Humoral immunity

Answer 22

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

Question 23

Antibodies

Answer 23

• target a specific antigen
• Contain 2 heavy and 2 light chains
• They have a constant region and a variable region; tip of the variable is the antigen-binding protein.

Question 24

What happens when the antigen-binding region is activated?

Answer 24

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 25

Opsonize

Answer 25

mark for destruction

Question 26

What are three ways that circulating antibodies work?

Answer 26

• opsonize for destruction
• cause clumping into insoluble complexes that are degraded
• neutralize pathogens

Question 27

Memory B-Cells

Answer 27

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

Question 28

Cell-mediated (cytotoxic immunity)

Answer 28

Centered on the functions of T-cells

Question 29

What hormone promotes T-cell development?

Answer 29

Thymosin

Question 30

Why do T-cells undergo maturation?

Answer 30

Positive and negative selection

Question 31

Positive T-cell selection

Answer 31

Only selecting t-cells that can react to antigen presented on MHC.

Question 32

Negative T-cell selection

Answer 32

causing apoptosis in self-reactive T-cells

Question 33

Helper T-cells

Answer 33

respond to antigen on MHC II and coordinate the rest of the immune response, secreting lymphokines to activate various arms of immune defense.

Question 34

Tb1 cells

Answer 34

secrete interfoeron gamma which activates microphages

Question 35

Tb2 cells

Answer 35

activate B-cells

Question 36

Cytotoxic T-cells

Answer 36

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

Question 37

Supressor T-cells

Answer 37

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

Question 38

Memory T-cells

Answer 38

serve a similar function to memory B-cells

Question 39

Autoimmune conditions

Answer 39

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

Question 40

allergic reactions

Answer 40

incite an inflammatory response

Question 41

Active immunity

Answer 41

Activation of B-cells that produce antibodies to an antigen

Question 42

Immunization is creating

Answer 42

active immunity

Question 43

Passive immunity

Answer 43

transfer of antibodies to an individual

Question 44

Lymphatic system

Answer 44

a circulatory system that consists of one-way vessels with intermittent lymph nodes

Question 45

thoracic duct

Answer 45

connects the lymphatic system to the cardiovascular system

Question 46

chylomicrons

Answer 46

equalizes fluid distribution, transports fats and fat-soluble compounds in chylomicrons