Lymphoid Tissues

Question 1

Primary lymphoid organs

Answer 1

Site where lymphopoiesis occurs( which is the production of lymphocytes)
Occurs in
Thymus
Foetal liver
Bone marrow
Yolk sac in foetus

Question 2

Bone marrow

Answer 2

Is the primary site of haematopoiesis
Foetus: occurs in all bones liver and spleen
Adult:flat bones vertebrae ribs ends of long bones and iliac bones

Question 3

Repertoire

Answer 3

Range of genetically distinct BCRs and TCRs present in a host. Large repertory means larger amount of threats can be recognized
Bcr means B cell receptors

Question 4

Red vs yellow bone marrow

Answer 4

Red produces blood cells yellow is fat

Question 5

Thymus function

Answer 5

T cell maturation and differentiation
Positive selection:can the T cell receptor signal
Negative selection:does it react against its own body

Question 6

Thymocytes

Answer 6

Immature T cells become thus when they migrate from bone marrow to the thymus

Question 7

Thymic involution

Answer 7

Shrinking of thymus with age

Question 8

Why do we need secondary lymphoid organs

Answer 8

TCR AND BCR outnumber T and B cells present in our bodies so require specialized lymphoid tissues and vessels for rapid migration of these cells to facilitate interactions with foreign antigens
So that lymphocytes can interact with antigens and other lymphocytes

Question 9

Secondary lymphoid organs

Answer 9

Spleen
Lymph nodes
Appendix
Mucosal associated lymphoid tissues

Question 10

Lymph nodes function

Answer 10

Activate and proliferate B and T lymphocytes
Facilitate interactions between immature lymphocytes and antigens

Question 11

Spleen function

Answer 11

Removal of waste products and aged or defective red boood cells
Activate and proliferate B and T lymphocytes
Facilitate interactions between immature lymphocytes and antigens
Highly attached to arterial circulation via splenic artery

Question 12

Gut associated lymphoid tissue

Answer 12

Peyers patches are specialized secondary lymphoid tissues
Highly enriched with B cells as high amount of foreign antigens are provided in the form of microbial products
Contain lots of germinal centers

Question 13

Germinal center

Answer 13

Where B cells undergo mutation and selection to generate high affinity antibodies

Question 14

Function of gut associated lymphoid tissues

Answer 14

Facilitate interactions between immature lymphocytes and antigens
Contains M cells which are a part of immune response which transport antigens from the lumen of the intestine to cells of the immune system

Question 15

Tonsils

Answer 15

Facilitate interaction between immature lymphocytes and antigen

Question 16

Lymphatic circulation

Answer 16

At high endothelial venules lymphocytes are able to migrate from blood to lymphatic tissue.

Question 17

Movement of cells in lymph nodes

Answer 17

T cells enter through high endothelial venules where they interact with dendritic cells and then leave through efferent lymphatic vessels