CHAPTER 15

Question 1

INNATE IMMUNITY

Answer 1

present before any exposure to pathogens and is effective from the time of birth (innate: existing by heredity); involves non-specific responses; physical barriers, internal cellular, and chemical defenses

Question 2

ADAPTIVE IMMUNITY

Answer 2

vertebrate only; (acquired immunity) develops after exposure to agents such as microbes, toxins, or other foreign substances; it involves a very specific response to pathogens

Question 3

PATHOGENS

Answer 3

bacteria, fungi, viruses; an organism or virus that causes disease

Question 4

BARRIER DEFENSES

Answer 4

in innate immunity; skin, mucous membranes (digestive, respiratory, urinary and reproductive tracts), secretions (tears, saliva, and mucous secretions contain lysosomes to destroy bacterial cell walls; acidic environment: stomach, skin/oils/sweat gland kill or prevent bacterial growth)

Question 5

PHAGOCYTOSIS

Answer 5

a type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophils, and dendritic cells)

Question 6

LYSOZYME

Answer 6

a membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists

Question 7

NEUTROPHILS

Answer 7

(most abundant WBC) phagocytic; ingest and destroy invaders; tend to self-destruct as they destroy

Question 8

MACROPHAGES

Answer 8

(most important WBC) ingest and destroy invaders, antigen presentation

Question 9

DENDRITIC CELLS

Answer 9

recognize pathogens and activate other immune cells by antigen presentation

Question 10

APOPTOSIS

Answer 10

a type of programmed cell death that is brought about by activation of enzymes that break down many chemical components in the cell

Question 11

GRANZYMES

Answer 11

an enzyme that breaks down proteins

Question 12

TOLL-LIKE RECEPTORS

Answer 12

found in mammals, act as the principal sensors of infection in mammals, bind to fragments of molecules characteristics of some pathogens but absent in the vertebrate body

Question 13

TYPES OF TLRS

Answer 13

TLR3: binds to double-stranded RNA (virus); TLR4: binds to lipopolysaccharide (bacteria); TLR5: recognizes flagellin (bacterial flagellum protein); TLR9: CpG DNA (DNA containing unmethylated CG sequences)

Question 14

ANTIMICROBIAL PEPTIDES

Answer 14

part of step 2 in the local inflammatory response; enters the tissue; signals released to attract neutrophils

Question 15

INFLAMMATORY RESPONSE

Answer 15

pain or swelling brought by signaling molecules (histamines and cytokines) released upon injury or infection

Question 16

PUS

Answer 16

a fluid rich in WBCs, dead pathogens, and cell debris from damaged tissue

Question 17

HISTAMINE

Answer 17

triggers blood vessels to dilate and become more permeable (vasodilation=> decreased BP)

Question 18

CYTOKINES

Answer 18

any group of small proteins secreted by a number of cell types, including macrophages and helper T cells, that regulate the function of other cells

Question 19

THYMUS

Answer 19

a small organ in the thoracic cavity of vertebrates where maturation of T cells is completed

Question 20

B LYMPHOCYTES

Answer 20

the lymphocytes that complete their development in the bone marrow and become effector cells for the humoral immune response

Question 21

T LYMPHOCYTES

Answer 21

the class of lymphocytes that mature in the thymus; they include both effector cells for the cell-mediated response and helper cells required for both branches of adaptive immunity

Question 22

HIV

Answer 22

the pathogen that causes AIDS (acquired immune deficiency syndrome); attacks and escapes the immune system

Question 23

ANTIGEN

Answer 23

a substance that elicits an immune response by binding to receptors of B cells, antibodies, or T cells

Question 24

EPITOPE

Answer 24

a small, accessible region of an antigen to which and antigen receptor or antibody binds; also called an antigenic determinant

Question 25

AIDS

Answer 25

acquired immune deficiency syndrome; it infects T(h) cells with high efficiency, impairing both humoral and cell-mediated immune response

Question 26

T CELL RECEPTOR

Answer 26

only recognizes antigens on the cell surface; recognizes the combination of the antigen and MHC molecule

Question 27

CLASS I MHC

Answer 27

on all nucleated cells; bind peptides produced by cell (broken down proteins inside cell and transported to cell surface); recognized by T(c) cells via T cell receptor and CD8

Question 28

CLASS II MHC

Answer 28

on APCs (eg. B cells, dendritic cells, and macrophages); helps T(h) cells recognize antigen on surface of APC; recognized by T(h) cells via T cell receptor and CD4

Question 29

HELPER T CELLS

Answer 29

a type of T cell that, when activated, secretes cytokines that promote the response of B cells (humoral response) and cytotoxic T cells (cell-mediated response) to antigens

Question 30

CYTOTOXIC T CELLS

Answer 30

a type of lymphocyte that, when activated, kills infected cells as well as certain cancer cells and transplanted cells

Question 31

CD4

Answer 31

accessory protein that helps an antigen receptor with binding the helper T cell to a complex

Question 32

CD8

Answer 32

accessory protein helping in binding the T9c) cell to a complex

Question 33

PERFORIN

Answer 33

a molecule that forms pores in infected cell membranes