Cells and Tissues of the Immune System

Question 1

Primary lymphoid organs

Answer 1

Thymus

Bone marrow

Question 2

Secondary lymphoid organs

Answer 2

Spleen
Lymph nodes
Mucosa associated lymphoid tissue (MALT)
Gut associated lymphoid tissue (GALT)
Cutaneous associated lymphoid tissues (CALT)

Question 3

Where lymphocytes are generated

Answer 3

Primary lymphoid organs

Question 4

Where adaptive immune responses are initiated

Answer 4

Secondary lymphoid organs

Question 5

Thymus

Answer 5

Site of maturation and development of self-tolerance for T cells

Question 6

Spleen

Answer 6

Largest secondary lymphoid organ

Specialized for trapping blood-borne antigens

Question 7

Highly endothelial venule

Answer 7

Enables lymphocyte migration into tissue

Question 8

Lymphocytes

Answer 8

B and T cells
Derived from lymphoid progenitors
Originate in bone marrow

Question 9

T helper cells

Answer 9

Mature in thymus
Release cytokines for stimulation of B cells, macrophage, and cytotoxic T cells
Recognize major histocompatibility complex (MHC) II on antigen
Activated by antigen presenting cells (especially dendritic cells) in secondary lymphoid organs

Question 10

Hematopoietic stem cells

Answer 10

Cells from which all immune cells develop

Question 11

T regulatory cells

Answer 11

Immunosuppressive functions
Suppress activation, cytokine production, and proliferation of other T cells
Shut down immune system after successfully eliminating invading organisms
Maintain tolerance

Question 12

Dendritic cells

Answer 12

Present antigens to T helper cells, activating them

Bridge between innate and adaptive immunity

Question 13

Neutrophils

Answer 13

Short lifespan (hours to days)
Myeloid lineage
Most numerous circulating white blood cell
Kill bacteria via phagocytosis, release of granules containing enzymes and reactive oxygen products, and extracellular traps

Question 14

Natural killer cells

Answer 14

Lymphoid cells 
Don't express antigen-specific receptors
Innate immune system components
Cytotoxic granules
Detect absence of MHC 1 on cells
Induce apoptosis of tumor and viral-infected cells

Question 15

Gamma delta T cells

Answer 15

Small subset of T cells
Adaptive immune system
T cell receptors that have gamma and delta chains
Recognize pathogen related ligands
Induce lysing of cancer cells

Question 16

T cytotoxic cells

Answer 16

Target and kill viral-infected or tumor cells
Release cytotoxins that trigger apoptosis
Recognize MHC I complexes
Arise in bone marrow
Mature in thymus

Question 17

Macrophages

Answer 17

Develop from monocytes
Remove foreign particles and cell debris
Phagocytose
Secrete cytokines
Once migrated into tissues, take on morphologies specific to microenvironment

Question 18

B cells

Answer 18

Specific for one antigen
Plasma cells secrete soluble antibodies
Mature in bone marrow
T helper cells present antigen, causing activation

Question 19

Which type of cells exhibit memory?

Answer 19

Lymphocytes (B and T cells)