Organs of the Immune System

Question 1

List types of immune tissue

Answer 1

1. Primary lymphoid organs = development sites of leukocytes, bone marrow and thymus
2. Secondary lymphoid tissue = sites where adaptive immune response is activated, where APCs present antigens to T cells, where B cells are stimulated to become antibody-secreting plasma cells. Includes lymph nodes, spleen, MALT, GALT

Question 2

What is lymph?

Answer 2

Lymph is created when fluid from blood seeps from capillaries into tissue, creating interstitial fluid, which the peripheral tissues and then is pulled back into circulation as lymph

Question 3

What are lymph nodes and their function?

Answer 3

Encapsulated organs interconnected with blood and lymph circulation.
Main function is to sample pathogens and antigens that are delivered to the lymph via filtering efferent vessels

Question 4

What is the function of the spleen?

Answer 4

• not directly connected to lymph circulation
  1. red pulp region = cortex - where old RBCs are filtered
  2. white pulp region = medulla - lymphoid regions with APCs, T and B cells.
• Fxn similarly to lymph nodes but pathogens are delivered via blood, not lymph

Question 5

What is MALT?

Answer 5

=mucosal associated lymphoid tissue

• In GI, respiratory, urogenital tracts
• fxns similarly to node and spleen: white pulp filters pathogens in the tracts

Question 6

What is GALT?

Answer 6

=gut associated lymphoid tissue

-includes tonsils, adenoids, appendix, Peyer’s patch

Question 7

What is BALT?

Answer 7

=bronchial associated lymphoid tissue