Tissues And Organs Of The Immune System

Front 1

Primary (central) lymphoid organ (Definition)

Back 1

Site of immune cell development

Front 2

What are the primary (central) lymphoid organs?

Back 2

Bone marrow

Thymus

Front 3

Secondary (peripheral) lymphoid organ (Definition)

Back 3

Site of mature immune cell residence and initiation of adaptive immune responses

Front 4

What are the secondary (peripheral) lymphoid organs?

Back 4

Spleen

Lymph nodes

Mucosal-associated tissue

Front 5

In bone marrow, hematopoiesis is ____

Back 5

Compartmentalized

Front 6

Islands of maturation (Definition)

Back 6

Compartmentalized areas of immune cell development in bone marrow

Front 7

How do mature cells exit the bone marrow?

Back 7

Via the central sinus

Front 8

What causes immune cells to migrate to the central sinus for exit from bone marrow?

Back 8

Chemokines

Front 9

What role do reticular cells play in the development of immune cells in bone marrow?

Back 9

They provide architecture and maturation signals (cytokines/growth factors)

Front 10

Besides reticular cells, what other cells provide cytokines/growth factors for immune cell development in bone marrow?

Back 10

Endothelial cells

Front 11

Genetic immunodeficiency can affect ____ cells or ____ cells

Back 11

Immune cells or reticular cells

Front 12

How do bone marrow reticular cells interact with developing immune cells?

Back 12

Via cytokines, chemokines, and growth factors

Via cell:cell signals

Front 13

____ is an important reservoir of neutrophils that can be rapidly mobilized in response to infection and stress

Back 13

Bone marrow

Front 14

How many neutrophils are produced in the bone marrow per day?

Back 14

100-200 billion

Front 15

What is the lifespan of a neutrophil?

Back 15

6-8 hours

Front 16

What are the components of a thymus lobule?

Back 16

Outer cortex

Inner medulla

Front 17

In what portion of a thymus lobule do T cells develop?

Back 17

Cortex

Front 18

What portion of a thymus lobule is responsible for immune tolerance?

Back 18

Medulla

Front 19

What is immune tolerance?

Back 19

A state of unpresponsiveness of the immune system, typically to self-tissue

Front 20

What is the role of cortical epithelial cells in a thymus lobule?

Back 20

They provide cell:cell signals, growth factors, and chemokines for T cell development (analogous to reticular cells of bone marrow)

Front 21

How do mature T cells enter the bloodstream (from the thymus)?

Back 21

Via venules in the corticomedullary junction

Front 22

How is the thymus gland implicated in immunosenescence?

Back 22

Age related thymic involution (replacement of parenchymal tissue with fat)

Front 23

What are CD molecules?

Back 23

Molecules found on cell surfaces that have a biological function

Front 24

What are thymocytes?

Back 24

Immature T cells

Front 25

When a T cell begins development, which (if any) CD molecules are expressed?

Back 25

None are expressed

Front 26

In the initial stages of T cell development, what happens to the thymocytes?

Back 26

Massive proliferation

Front 27

What causes developing thymocytes to migrate from the cortex of a thymus lobule toward the medulla?

Back 27

Chemokines

Front 28

What percentage of the initial T cells survive to maturation?

Back 28

~3%

Front 29

As thymocytes migrate toward the medulla of thymus lobules, what CD molecules are expressed?

Back 29

CD4, CD8, and CD3/TCR

Front 30

What CD molecules are expressed by mature helper T cells?

Back 30

CD4 and CD3/TCR

Front 31

What CD molecules are expressed by mature cytotoxic T cells?

Back 31

CD8 and CD3/TCR

Front 32

How does a thymus lobule contribute to immune tolerance?

Back 32

By destroying any T cell that recognizes self-tissue (negative selection)

Front 33

The presence of what molecule can be used to identify a cell as a T cell?

Back 33

CD3

Front 34

The spleen is the site of adaptive immune responses to ____ antigens

Back 34

Blood-borne

Front 35

How are blood vessels carried to lymphoid follicles within the spleen?

Back 35

Via fibrous trabeculae

Front 36

Periarteriolar lymphoid sheath (PALS) (Definition)

Back 36

T cell-rich area surrounding central arteriole in the spleen

Front 37

Lymphoid follicle (definition)

Back 37

Outpocket of lymphocytes from a periarteriolar lymphoid sheath (white pulp)

Front 38

Lymphoid follicles are rich in what type of cell?

Back 38

B cells

Front 39

Primary lymphoid follicle (Definition)

Back 39

Area of spleen composed of resting B cells

(Resting follicle)

Front 40

Secondary lymphoid follicle (Definition)

Back 40

Area of spleen composed of an outer mantle of resting B cells with a central germinal center of proliferating B cells

(Active follicle)

Front 41

What is the role of red pulp in the spleen?

Back 41

Eliminates RBCs via macrophages

Front 42

Does lymph drain into the spleen?

Back 42

No

Front 43

In what area of a lymphoid follicle does the adaptive immune response begin?

Back 43

The perifollicular zone

Front 44

How do the necessary cells for an adaptive immune response reach the perifollicular zone of a lymphoid follicle?

Back 44

Via the central arteriole

Front 45

How is an adaptive immune response induced in the spleen?

Back 45

A dendritic cell presents an antigen to a T cell, which helps a B cell respond

(D:T:B)

Front 46

Lymph nodes are the sites of adaptive immune response to ____ antigens

Back 46

Tissue-borne

Front 47

What are lymph nodes?

Back 47

Filtration units for lymphatic drainage

Front 48

How are microorganisms and antigens carried to lymph nodes?

Back 48

Via afferent lymphatic vessels

Front 49

Where do afferent lymphatic vessels deposit lymph?

Back 49

In subcapsular sinuses

Front 50

When do dendritic cells migrate from tissue to lymph nodes?

Back 50

At all times

Front 51

How do naive lymphocytes (T and B cells) enter a lymph node?

Back 51

Via specialized post-capillary venules called high endothelial venules (HEV)

Front 52

How do lymphocytes (T and B cells) exit a lymph node?

Back 52

Via a single efferent lymphatic

Front 53

What is contained within the lymph node cortex?

Back 53

Follicles and T cell-rich regions (analogous to spleen)

Front 54

What is contained within the lymph node medulla?

Back 54

Macrophages and plasma cells

Front 55

How does the lymphatic system increase the odds of antigens being recognized?

Back 55

When lymph leaves one lymph node via an efferent lymphatic vessel, it travels to another lymph node, and then another, and so on

Front 56

Mucosal-associated lymphoid tissue (Definition)

Back 56

Lymph node-like regions in subepithelia of all mucosal tissue sites that function like spleen/lymph nodes

Front 57

Examples of mucosal-associated lymphoid tissue

Back 57

GALT (gut-associated)

BALT (bronchial/tracheal-associated)

NALT (nose-associated)

VALT (vulvovaginal-associated)

Front 58

Mucosal-associated lymphoid tissue can be ____ or ____ structures

Back 58

Organized or diffuse

Front 59

Examples of mucosal-associated lymphoid tissue in organized structures

Back 59

Tonsils

Peyer's pathces

Appendix

Front 60

Example of mucosal-associated lymphoid tissue in diffuse structures

Back 60

Intestinal lamina propria (effector cells activated in lymphoid follicles)