Lymphoid System

Question 1

Which of the following is a primary/ central lymphoid organ?

a. Mucous associated lymphoid tissue
b. Gut associated lymphoid tissue
c. Spleen
d. Bone marrow
e. Lymph node

Answer 1

d. Bone marrow

Question 2

Which of the following is a signaling molecule for B cells?

a. CAM’s
b. VLA
c. SCF
d. VCAM’s

Answer 2

c. SCF (stem cell factor)

**the others are adhesion molecules

Question 3

Which immunoglobulin do immature B cells have receptors for?

a. IgD
b. IgA
c. IgM
d. IgG

Answer 3

c. IgM

Question 4

The thymus has ___ which are immature pro B cells that left the bone marrow and invaded the cortex of the thymus through blood.

Answer 4

Thymocytes

Question 5

True/False: Cortical epithelial cells of the thymus have already been exposed to antigen that belongs to the body.

Answer 5

False

**Thymocytes

Question 6

True/False: Only mature T cells leave the thymus and populate peripheral lymphatic organs.

Answer 6

True

Question 7

What is the adhesion molecule that attaches T cells to surface molecules?

a. Desmin
b. Cadherin
c. Integrin
d. Cellular adhesion molecules

Answer 7

c. Integrin

Question 8

What is the name of special entry sites for blood circulating lymphocytes that lead them to the peripheral lymphoid organs?

Answer 8

High endothelial venules (HEV)

Question 9

What are the three cells that make up the lymphoid system?

Answer 9

Lymphocytes
Accessory cells (APC)
Epithelial cells

Question 10

The lymphoid system involves cells involved in the ____ immune response (lymphocytes, accessory cells, APC) that are localized and concentrated in anatomically defined organs and tissues.

Answer 10

Adaptive immune response

Question 11

Where are lymphoid stem cells produced in a very young fetus?

Answer 11

Yolk sac mesoderm and fetal liver

Question 12

Where are lymphoid stem cells produced in older fetuses and neonates?

Answer 12

Bone marrow

Question 13

Which of the following is the primary lymphoid organs of B cell maturation in birds?

a. Bone marrow
b. Spleen
c. Bursa of Fabricious
d. Peyer’s patches

Answer 13

c. Bursa of Fabricious

Question 14

Which of the folllowing is the primary lymphoid organ that is the site of T cell development and maturation?

a. Bone marrow
b. Peyer’s Patches
c. Thymus
d. Bursa of Fabricious

Answer 14

c. Thymus

Question 15

Which cytokine is important for the maturation and proliferation of thymocytes?

a. IL-10
b. IL-2
c. IL-6
d. IL-7

Answer 15

d. IL-7

Question 16

True/False: Thymocytes whose TCR’s either cannoy recognize antigen -MHC complexes or whose TCR react strongly with self antigen - MHC complexes die by apoptosis.

Answer 16

True

Question 17

Thymic involution begins within the ___ which may disappear completely whereas ____ remnants persist.

Answer 17

Cortex, medullary

Question 18

True/False: The majority of B cells in birds are going to die through apoptosis.

Answer 18

True

Question 19

Which of the following is true regarding stromal cells?

a. They secrete various cytokines that are required for T cell development
b. Responsible for the selection of mature B cells
c. Immature B cells that acquire B cell antigen receptors that recognize self proteins are allowed to die
d. All the above are true

Answer 19

c. Immature B cells that acquire B cell antigen receptors that recognize self proteins are allowed to die

Question 20

Where are peyer’s patches found?

Answer 20

Within the walls of all three segments of small intestine

Question 21

Which of the following is false?

a. Lymph node captures antigen from epithelium and connective tissue
b. Blood borne antigens are captured by APC’s in the spleen
c. Skin, respiratory tract and gastrointestinal tract are the 3 major portals of antigen entry into the body
d. All the above are true

Answer 21

d. All the above are true

Question 22

Which of the following is the only lymphatic organ with both afferent and efferent lymph vessels?

a. Spleen
b. Bone marrow
c. Thymus
d. Lymph nodes

Answer 22

d. Lymph nodes

Question 23

True/False: The paracortex of lymph nodes contains mostly B cells and the primary follicles contain mostly T cells.

Answer 23

False

**paracortex contain T cells and primary follicles contain mostly B cells

Question 24

Which of the following regarind the lymph node is false?

a. Germinal centers develop in response to antigenic stimulation of B cells
b. Lymphocytes leave the node through the high endothelial venules in the secondary follicles
c. Primary follicles mainly contain mature B cells, follicular dneditic cells and macrophages
d. Paracortex contain mostly T cells while the medulla contains mostly macropahges, antibody secreting plasma cells and some lymphocytes

Answer 24

b. Lymphocytes leave the node through the high endothelial venules in the secondary follicles

**lymphocytes enter the node from the circulation through high endothelial venules in the paracortex

Question 25

What is the largest secondary lymphoid organ where antibodies are produced?

Answer 25

Spleen

Question 26

True/False: The spleen also contains high endothelial venules to help filter blood.

Answer 26

False ***only secondary lymphoid organ its not found in is the spleen

Question 27

Which of the following is true? a. HEV's are found in all secondary lymphoid organs except lymph nodes b. If a naive T cell doesn't encounter an antigen it stays within the organ c. When antigens enter the antigen specific lymphocyte is activated and changed into effector or memory cells d. There is only a certain amount of lymphocytes that are moved into the nodes

Answer 27

c. When antigens enter the antigen specific lymphocyte is activated and changed into effector or memory cells

Question 28

True/False: Rearrangement of the immunoglobulin heavy chain gene must occur first before rearrangement of the immunoglobulin light chain gene.

Answer 28

True

Question 29

Which of the following leads to the production of the light chain protein and mu protein of the heavy chain? a. Transcription of RNA b. Splicing of mRNA c. DJ joined DNA d. Translation of chains

Answer 29

d. Translation of chains

Question 30

What signaling molecules transmit biochemical signals after the variable region of the BCR binds to its antigen? a. CD79 b. IL-7 c. CD3 d. MHC II

Answer 30

a. CD79

Question 31

A B cell that sheds its pre B cell IgM receptor is known as an ____ B cell.

Answer 31

Immature

Question 32

Which of the following terms refers to a process that attempts to rescue a self reactive B cell from undergoing apoptosis by reactivating the RAG 1 and RAG 2 genes and begins further rearrangement of the light chain genes? a. Anergy b. Receptor editing c. Deletion d. Clonal ignorance

Answer 32

b. Receptor editing

Question 33

Which lymphatic organ does not involute? a. Bursa of Fabricious b. Spleen c. Ileal Peyer's patch d. Thymus

Answer 33

b. Spleen

Question 34

Pluriportent stem cells differentiate to give rise to all blood cells. The stem cells reside primarily in the: a. Spleen b. Thymus c. Bone marrow d. Liver

Answer 34

c. Bone marrow

Question 35

Which of the following is considered a foreign antigen? a. Viruses b. Bacteria c. Fungi d. All the above

Answer 35

d. All the above

Question 36

WHich of the following do not influence the potency and diversity fo a host's immune system response to an antigen and are not considered "best antigens"? a. Foreign b. Non-degradable c. Molecularly large d. Chemically complex

Answer 36

b. Non-degradable

Question 37

Tens of billions of B cells are generated every day in the bone marrow, how many survive? a. 90% b. 10% c. 50% d. 0% e. 17%

Answer 37

c. 50%

Question 38

Which of the following is correct regarding where B and T cells mature, just prior to traveling to lymph nodes? a. B cells mature in the thymus; T cells mature in the thyroid b. B cells mature in bone marrow; T cells mature in thymus c. B cells mature in the spleen; T cells mature in the Bursa of Fabricious d. B cells mature in the thymus; T cells mature in the peyers patches

Answer 38

b. B cells mature in bone marrow; T cells mature in thymus

Question 39

In the event of re-infection with the same pathogen, which immune cell allows for a quick response? a. Null cell b. Helper T cell c. Memory B cell d. Plasma cell

Answer 39

c. Memory B cell

Question 40

Which of the following statements regarding the spleen is the least accurate? a. It is considered a secondary lymphatic organ b. It is the largest "lymph node" in the body c. The spleen filters antigens from the blood d. It combines the innate and adaptive immune system in a unique way d. Naive lymphocytes migrate from the blood into the spleen through high endothelial venues (HEV)

Answer 40

d. Naive lymphocytes migrate from the blood into the spleen through high endothelial venues (HEV)

Question 41

Which of the following is not a T cell signaling molecule? a. CD4/ CD8 b. CD28 c. CD3 d. CD17 e. zeta zeta molecules

Answer 41

d. CD17

Question 42

What is the T cell adhesion molecule?

Answer 42

Integrins