2: Cells and tissues of the immune system

Question 1

what happens to eosinophils after leaving bone marrow

Answer 1

migrate to the spleen where they mature, then migrate into tissues

Question 2

what are eosinophils responsible for (3)

Answer 2

• phagocytosis and killing of parasites
• Fc receptors on surface to bind antibodies
• produce cytokines

Question 3

what do eosinophilic granules contain (3)

Answer 3

• phosphatase
• peroxidase
• toxic proteins

Question 4

what do basophil granules contain

Answer 4

inflammatory molecules (histamine, serotonin)

Question 5

what do basophils do

Answer 5

play a role in killing of parasites due to presence of FceRI

Question 6

what do mast cells do

Answer 6

play a role in killing of parasites due to presence of FceRI

Question 7

what do mast cell granules contain

Answer 7

vasoactive amines (histamine, serotonin)

Question 8

what is adaptive immune response mediated by

Answer 8

lymphocytes

Question 9

what is adaptive immunity specific to

Answer 9

a given molecule (epitope –> 8-12 amino acids)

Question 10

what does adaptive immune system do (3)

Answer 10

• has surface receptors for antigens on pathogens or particles
• provides specific immunity to antigens
• provides memory of specific antigens

Question 11

what do b cells do (3)

Answer 11

• produce antibodies
• antibodies bind antigens
• antibodies interact with components of the innate immune system

Question 12

what do t cells do (3)

Answer 12

• recognize processed antigen on host cells (cell mediated immunity)
• helper t cells activate or regulate activities of other cells
• cytotoxic t cells kill host cells bearing a foreign antigen

Question 13

what is clonal selection

Answer 13

lymphocytes undergo clonal selection based on an individual cell having the correct receptor for a very small, defined part of a larger antigen

Question 14

what happens to lymphocyte receptors

Answer 14

genome rearranges randomly at the site where the receptors are encoded –> generates cells of the same type but with different receptors

Question 15

what do lymphoid organs have sites for

Answer 15

• sites where lymphocytes develop and/or contact and respond to specific antigens
• points of differentiation, antigen and immune cell collection, and adaptive immune responses

Question 16

places of differentiation and activation

Answer 16

• differentiation: primary organ

- activation: secondary organ

Question 17

what are primary lymphoid organs sites of

Answer 17

production and differentiation for lymphocytes

Question 18

examples of primary lymphoid organs

Answer 18

• bone marrow or bursa of fabricus (avian): b cells
• thymus: t cells
• peyers patches: b cells (especially ruminants)

Question 19

what are 2 primary organs that are also secondary

Answer 19

bone marrow, bursae

Question 20

what can serve as sites for lymphoid production when excessive blood cell production is demanded

Answer 20

liver and spleen

Question 21

what are supporting cells in bone marrow and what do they support

Answer 21

stromal cells –> lymphopoiesis and myelopoiesis

Question 22

what are peyers patches

Answer 22

structures located along the gastrointestinal tract within the lamina propria

Question 23

what do peyers patches contain

Answer 23

large numbers of lymphocytes, mostly b cells

Question 24

how are peyers patches arranged

Answer 24

arranged in follicles with b cells central and t cells surrounding them

Question 25

what are peyers patches important for

Answer 25

- immune responses for ingested antigens | - sites of primary b cell differentiation

Question 26

what do peyers patches do

Answer 26

take up antigen from the gut and transport it to draining lymph nodes

Question 27

what are secondary lymphoid organs (definition)

Answer 27

sites where lymphocytes develop and/or contact and respond to specific antigens (collection and response points)

Question 28

examples of secondary lymphoid organs (5)

Answer 28

- SPLEEN - LYMPH NODES - tonsils - peyers patches - bone marrow

Question 29

2 parts of spleen and their functions

Answer 29

- red pulp contains phagocytes | - white pulp contains lymphocytes, mostly B cells but also T cells

Question 30

2 components of white pulp in spleen

Answer 30

- splenic nodules (contain b lymphocytes) | - periarterial lymphatic sheaths (t-lymphocytes)

Question 31

what is the largest lymphoid organ

Answer 31

spleen

Question 32

what is the spleen the major site of

Answer 32

adaptive immune responses to blood-borne pathogens (filters out effete red blood cells)

Question 33

what are lymph nodes points of

Answer 33

convergence for cells in the blood and lymph systems

Question 34

what do lymph nodes collct

Answer 34

extracellular fluid (lymph) from tissues for return to the blood

Question 35

what do lymph nodes contain

Answer 35

b and t cells in segregated regions

Question 36

what causes swollen lymph nodes

Answer 36

b cell proliferation in germinal centers

Question 37

what do somatic mutations in germinal centers do

Answer 37

help with adaptive immune response

Question 38

what is lymph node divided into

Answer 38

- outer cortex - inner medulla - surrounded by a capsule

Question 39

where do most lymphocytes migrating to lymph nodes enter from

Answer 39

peripheral blood

Question 40

what can only lymphocytes interact with and exravasate through

Answer 40

high endothelial venules (HEVs) to migrate into lymph node parenchyma

Question 41

what are high endothelial venules (HEVs)

Answer 41

-specialized capillaries of lymphoid tissues where lymphocytes exchange from the blood

Question 42

what do endothelial cells in the HEV lack

Answer 42

tight junctions