lymphoid system

Question 1

what does MALT stand for

Answer 1

Mucosa associated lymphoid tissue

Question 2

what does the MALT do and where can you find it in the body

Answer 2

• lines mucosa
• digestive tract, respiratory tract, urinary tract, reporductive tract

Question 3

What structures are included with in the MALT

Answer 3

• tonsils
• peyer patches
• appendix
• lymphoid nodules

Question 4

what is NOT is not part of the MALT

Answer 4

PALS - peri-arteriole-lymphoid - sheets

Question 5

where can you find PALS

Answer 5

surrounding the center artiriole in the spleen

Question 6

when are lymphoid nodules part of the MALT?

Answer 6

only when they are scattered by the mucosa but when they are in the lymph nodes or the spleen ( inside organs) they arent part of the MALT

*** if he doesnt specify where the lymphoid nodules are within the organ then they are part of the MALT

Question 7

what lymphoid cells are part of the MALT and where are they located

Answer 7

• B cells - in the nodules
• T cells - in adajacent areas

Question 8

where are B and T lymphocytes produced

Answer 8

B- in the bone marrow
T- in the thymus

Question 9

what is the innate immunity
- what immune cells hare present here

Answer 9

• immediate and non specific response
• uses natural killer cells

Question 10

what is adaptive immunity (3)
- what immune cells are present here

Answer 10

• acquired gradually through exposure
• involves B and T lymphocytes ( T helper & cytotoxic)
• have memory of past infections

Question 11

where are macrophages present

Answer 11

• CT
• lymphoid organs
• bone marrow
• pleural and peritoneal cavities

Question 12

what are the functions of macrophages (2)

Answer 12

• produce cytokine and inflammation factors
• antigen processing and presenting

Question 13

what are kupffer cells

Answer 13

macrophages of the liver

Question 14

what are microglial cells

Answer 14

marophages of the CNS

Question 15

what are langerhan cells

Answer 15

antigen processing and presenting the epidermis

Question 16

what are dendritic cells

Answer 16

antigen processing and presenting in the lymph nodes and spleen

Question 17

what are lymph nodes derived from
- what immune cells are included and what are their function

Answer 17

• mesenchyme
• B&T cells for filtration of lymph

Question 18

what are the functions of lymph nodes(2)

Answer 18

• synthesize antibodies ( mainly IgG)
• circulates lymphocytes

Question 19

what is the the passage of lymph through the lymphnodes?

Answer 19

• it enters through the trabiculae and goes to the medullary passage

Question 20

where do lymphocytes enter high endothelial venuels in the lymph nodes

Answer 20

paracortex

Question 21

what is the funtion of the higher endothelial venuels (HEVS ) in the lymph nodes

Answer 21

they are where the lymphocytes and macrohphages exit and enter the blood to become localized in the lymph nodes

Question 22

where are T-lymphocytes in the spleen?

Answer 22

PALS

Question 23

where are T- lymphocytes localized in the lymph nodes

Answer 23

in the paracortex

Question 24

where are B-lymphocytes localized in the lymphnodes

Answer 24

in the cortex

Question 25

what is the function of the germinal center of lymph nodes - what is localized here

Answer 25

are where lymphocytes proliferate - B lymphocytes

Question 26

what occurs in thymus

Answer 26

maturation of T lymphocytes

Question 27

what is the proccess of the maturation of T lymphocytes

Answer 27

- positive and negative selection

Question 28

What step of T lymphocyte maturation is positive selection involved in and what is the process

Answer 28

- First step in maturation - Happens in the cortex - Checks to see if T cells bind to any MHC molecule presented - If yes, then survive and move to medulla of thymus >>Weak binding is good enough - If no, then death by neglect

Question 29

What step of T lymphocyte maturation is negative selection involved in and what is the process

Answer 29

- Second step in maturation - Happens in medulla of thymus - Checks to see if T cells bind to MHC I (self-antigen) - If yes, then the cell dies by apoptosis ANY binding to MHC I results in cell death - If no, then the cell has survived maturation and it can leave the thymus to function in the immune system - Only 2% of T cells that go in survive this process

Question 30

who is the thymus larger in and why

Answer 30

- larger in kids - undergoes involution- parenchyma is replaced with adipose tissue

Question 31

what does the medulla of thymus contain

Answer 31

- contains hassels corpuscles

Question 32

what is the function of the hassles corpuscles (2)

Answer 32

- highly acitve and produce hormones to help lymphocytes differentiate when located on the periphery of the thymus - role in negative selection

Question 33

what do lymphoid nodules in the spleen contain - what are they segregated from?

Answer 33

- B lymphocytes - T lymphocytes in the PALS surrounding the central arteriole

Question 34

what do T lymphocytes have on their cells surface? and what are they

Answer 34

- markers - CD4 and CD8 markers

Question 35

which T cells are marked with CD8 markers and which are marked with CD4? what do these cells do?

Answer 35

- CD8>> cytotoxic T cells >>trigger apoptosis in MHC class 2 presenting cells>> triggered by T helper cells - CD4>>T helper cells>> >> produce cytokines to promote differentiation of B cells in to plasma cells which stimulates macrophages - Can become long lived memory T cells which help the immune system recognize antigens from past infections

Question 36

what do B lymphocytes have on their cell suraface

Answer 36

immunoglobulins

Question 37

what does the proccess of T-lymphocyte maturation require and what produces it?

Answer 37

- hormones>>thymopoetic/thymosin - produced by the thymic epithelial cells/ epithelial reticular cells

Question 38

what is the subdivision of the thymus and what do they contain?

Answer 38

lobules(lobes) >> contain a cortex and a medulla

Question 39

where does positive selection of T lymphocyte happen in Thymus lobueles? negative selection?

Answer 39

- positive >>cortex -- negative >>medulla

Question 40

What is the maturation of T lymphocytes independent of? What does it lead to?

Answer 40

- Foreign antigens - leads to the differntitation of T lymphocytes from immunoincompetent to immunocompetent

Question 41

what is IgE

Answer 41

Antibody present in plasma in the presence of allergens and binds to IgE receptors on basophils

Question 42

what is IgG

Answer 42

most common antibody in the plasma - neutralized antigens

Question 43

what is IgA

Answer 43

antibody present in secretion - seen in saliva and milk production

Question 44

which cells are involved in antigen presentation

Answer 44

- macrophages - dendritic cells in lymphoid organs - thymic epithelial cells

Question 45

what is MHC 1? how do T lymphocytes react ? where are they present where are they not?

Answer 45

- self antigen - T cells recognize this and dont bind to cells this marker is on - on the surface of all nucleated cells EXCEPT RBCs and platelts bc dont have nuclei

Question 46

what is MHC class 2? how do T lymphocytes react?

Answer 46

- on the sell surface of foreign antigens - T lymphocytes recognize this maker, bind, and eliminate the marked cell

Question 47

which cells present both MHC class 1 and 2

Answer 47

- monocytes/macrophages > present foreign antigens on MHC2 - Thymic epithelial cells>> present the antigens on MHC2 - Lymphocytes