Lecture #24: Immune and Lymphatic System 1 Flashcards Preview

Histology -- Zach H. > Lecture #24: Immune and Lymphatic System 1 > Flashcards

Flashcards in Lecture #24: Immune and Lymphatic System 1 Deck (92):
1

Does the innate immunity lack immune specificity and memory?

Yes, the innate immunity system lacks immune specificity and memory.

2

What are the two different parts of our immune system?

Innate Immunity and Acquired Immunity

3

Is the innate or acquired immune system more powerful?

Acquired Immune System

4

True or False:

The innate immune system develops in response to antigens?

False - the acquired immune system is developed in response to antigens.

5

Which part of the immune system displays specificity and memory?

Acquired Immunity

*the innate immune system lacks specificity and memory.

6

What is the definition of passive immunity?

Passive immunity -> temporary immunity due to donated antibodies (i.e., transplacental passing of maternal antibodies to fetus).

7

What is the definition of active immunity?

Active immunity -> long-lasting/permanent immunity due to self exposure to antigen resulting in memory T-cells and B-cells specific for antigen.

8

What is the definition of cell-mediated immunity?

Cell-mediated Immunity -> an immune response that does not involve antibodies, but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.

9

What is the definition of humoral immunity?

Humoral Immunity -> also called the antibody-mediated beta cellularis immune system, is the aspect of immunity that is mediated by macromolecules (as opposed to cell-mediated immunity) found in extracellular fluids such as secreted antibodies, complement proteins and certain antimicrobial peptides.

10

What two lymphoid organs are considered primary lymphoid organs?

Thymus
Bone Marrow

11

Which 3 organs are considered secondary lymphoid organs?

Lymph Nodes
Spleen
Tonsils

12

In which type of lymphoid organs do lymphocytes originate in and then where do they reside after maturity?

Lymphocytes originate in primary lymphoid organs and then take up residence in secondary lymphoid organs.

*Primary Lymphoid Organs - precursor cells mature into immunocompetent cells. Each cell is programmed to recognize a specific antigen.

*Secondary Lymphoid Organs - trapped antigens stimulate clonal expansions of mature T and B cells.

13

True or False:

Lymph follicles (nodules) are not enclosed within a capsule.

True

14

What is the function of lymph follicles (nodules)?

Is the site of B-cell localization and proliferation.

15

Are virgin B-cells found in the primary or secondary follicles (nodules)?

Virgin B-cells are found in the primary follicles (nodules).

16

What are primary follicles (nodules)?

Primary follicles are spherical, tightly packed accumulations of virgin B-cells and dendritic reticular cells that have not benn exposed to antigens.

17

What are secondary follicles (nodules)?

Secondary follicles are derived from primary follicles that have been exposed to non-self antigens. They are not present at birth.

18

What kind of cell type is the corona (cortex) of secondary lymph follicles composed of?

The corona (cortex) of the secondary lymph follicle is composed of densely packed B lymphocytes.

19

What type of cells are the germinal center of the secondary lymph follicle composed of?

The germinal center of the secondary lymph follicle is composed of B lymphocytes, memory B-cells, plasma cells, dendritic reticular cells which function as antigen-presenting cells.

20

True or False:

Lymph capillaries are present in secondary lymph follicles.

False - lymph capillaries are NOT present.

21

Do the same arterioles and venules supply the cortex and germinal center of a secondary lymph follicle?

No, separate arterioles and venules supply the cortex and germinal center of the secondary lymph follicle.

22

What cell type are the first responders in the innate immune system?

Neutrophils are the first responders in innate immunity.

23

What cell types make up the diffuse lymphoid tissue?

Scattered clusters of plasma cells, macrophages, and lymphocytes located in the connective tissue stroma and various other sites.

24

Which layer of the dermis is the subcutaneous-associated lymphoid tissue found?

Papillary Layer or the Dermis

25

True or False:

The MALT, BALT, and GALT are all lamina propria-associated lymphoid tissues.

True

**MALT = mucosal-associated lymphoid tissue
**BALT = bronchial-associated lymphoid tissue
**GALT = gut-associated lymphoid tissue

26

Is the diffuse or aggregated lymphoid tissue in contact with the epithelium?

Aggregated lymphoid tissue is beneath and in contact with the epithelium.

*includes various tonsils and Peyer's patches in the ileum

27

Both B-cells and T-cells are derived from the bone-marrow, but in which organ do each differentiate?

B-cells -> differentiate in bone-marrow and are derived from the bone-marrow

T-cells -> differentiate in the thymus and are derived from the bone-marrow

28

T-cells differentiate in the thymus in to what two different T-cell types?

1) helper T cells
2) cytolyticT cells

29

What are the 3 antigen-presenting accessory cells of the immune system, and where are they derived from?

1) macrophages; derived from monocytes

2) dendritic cells; derived from monocytes

3) follicular dendritic cells; derived from lymph nodes

30

The maturation of B-cells involves the appearance of certain cell surface receptors. Which MHC class protein is needed to signal B-cell maturation?

MHC class II proteins

31

Maturation of B-cells involves the appearance of certain cell surface receptors. What 2 antibodies are involved in B-cell maturation?

IgM and IgD

32

Maturation of B-cells involves the appearance of certain cell surface receptors. Which 2 receptors are involved in this maturation?

Complement Receptors and Ig Fc Receptors

33

What are the 5 classes of antibodies?

IgA
IgD
IgG
IgM
IgE

34

What are the two chains of the antibody structure and what function does the highly and less variable regions of the antibody do?

Light and Heavy Chains

Highly Variable Regions:
>Fab fragment
>Recognizes antigen

Less Variable Regions:
>Fc fragment
>Binds antibody to cells

35

Where in the body is the IgA antibody typically found?

Found in saliva, milk, GI, and Respiratory Tracts

36

Where is the IgD antibody typically found in the body?

Found on surface of B-cells traveling to lymphoid organs.

37

Which antibody is typically in the blood in highest concentration?

IgG

38

Which antibody is responsible for most antibody activity?

IgG

39

Which antibody is associated with allergic responses?

IgE

40

What is the first antibody class expressed by developing B-cells?

IgM

41

What does MHC stand for and what is its function of the MHC gene products?

MHC -> Major Histocompatibility Complex

Function -> main function of MHC gene products is the presentation of antigenic peptides to T-cells.

42

What type of cell surface is MHC I expressed on?

MHC I -> expressed on the surface of all cells except trophoblast and red blood cells.

43

What type of cell surface is MHC II expressed on?

MHC II -> expressed on the surface of B-cells and antigen-presenting cells.

44

What do CD8+ T-cells recognize?

Peptide fragments of foreign proteins bound to MHC class I on the surface of cells.

*Recognize antigens bound to MHC class I molecules.
*CD8 is a member of the Ig Superfamily.
**Both the CD8 and the T-cell antigen receptor are required for the binding of MHC class I protein fragments.

45

What do CD4+ T-cells recognize?

Peptide fragments of foreign proteins bound to MHC class proteins on surface of APCs.

*Recognize antigens bound to MHC class II molecules.

46

Where are T-cells produced and where do they travel to mature?

Pre T-cells develop in bone marrow and travel to the thymus to complete maturation.

47

What is the function of the CD4+ T-cell?

CD4+ T-cells are called "helper cells" and assist:
> assist CD8+ cell differentiation
> assist B cell differentiation

48

What two proteins are released by the CD8+ T-cell?

Perforins and Fas Ligand

49

Fill in the Blank:

CD8+ T-cells are __________ of cellular ______________.

mediators ; immunity

50

What are CD8+ T-cells also known as?

Cytolytic T-cells

51

True or False:

Cytolytic T-cells bind to an antigen presenting cell.

True

52

Which T-cell is called the "natural killer (NK)" T-cells?

CD16+ T-cells

53

Activated (by tumor cell antigens) T-helper cells release cytokines. What are these released proteins?

Interleukin-2
>stimulates proliferation of NK cells

Interferon-gamma
>activates NK cells

Macrophage activating factor (MAF)
>activates macrophages

Chemotactic factor

Tumor Necrosis Factor (TNF-beta)
>kills tumor cells directly

54

What protein activates NK cells?

Interferon-gamma

55

Which interleukin stimulates the proliferation of NK cells?

Interleukin-2

56

What does MAF (macrophage activating factor) do?

activates macrophages

57

What cytokine released by T-helper cells kills tumor cells directly?

Tumor Necrosis Factor (TNF-beta)

58

True or False:

T-cells recognize peptide antigens only when they are presented bound to MHC.

True

*Cytolytic T-cells recognize an antigen presented by class I MHC molecules.

*Helper T-cells recognize an antigen in association with class II MHC molecules.

** This property is called MHC restriction!

59

True or False:

Co-receptor CD4+ binds to the alpha3 region of class I MHC.

False - Co-receptor CD8+ bonds to the alpha3 region of class I MHC.


**The CD4+ co-receptor binds to the beta2 region of class II MHC.

60

True or False:

The co-receptor CD4+ binds to the beta2 region of class II MHC.

TRUE

61

What receptor on the cytolytic T-cell binds to the class 1 MHC on the antigen-presenting cell (macrophage)?

Thymus Cell Receptor (TCR)

62

The thymus cell receptor (TCR) on what type of T-cell binds to the class II MHC protein presented on the antigen-presenting cell (macrophage)?

Helper T-cell (CD4+ T-cell)

63

Foreign proteins are broken down into fragments, some of which have antigenic properties. What are these short antigenic property containing fragments known as?

epitopes

64

In T cell-mediated immunity macrophage phagocytize foreign material and present epitopes (antigens) on the surface of the macrophage that are bound to MHC-II. This MHC II/antigen complex is presented to activated helper T-cells, in which the activated T-cell undergoes mitosis. What do some of the daughter cells secrete and what type of cell does some of the daughter cells from the activated T-cell become?

Some daughter cells become memory cells.

Some daughter cells secrete interleukins.

65

In T cell-mediated immunity, what attracts the B-cells?

T cells attract B-cells

66

Towards the end of T cell-mediated immunity T cells attract B cells, in which now have access to free antigens. The exposure to antigens cause the B-cells to undergo mitosis. What are two different cell types that these daughter cells become post mitosis?

Some daughter cells become plasma cells.
>secrete appropriate antibodies

Some daughter cells become memory cells.

67

What is the complement system?

The complement system is an array of about 20 serum proteins which are synthesized in the liver and found in the blood.
>Classic Pathway
>Alternate Pathway

68

How is the classic pathway activated?

The classic pathway cascade is activated by antibody binding to a pathogen.

69

How is the alternate pathway activated?

The alternate pathway cascade is directly activated by the pathogen.

70

What does the complement system facilitate in the presence of a pathogen?

The complement system facilitates inflammatory responses.


*The complement cascade (either pathway) involves coating the pathogen with complement initiating the cascade.

71

Look Over The Schematic For Classical Complement Pathway

In the book and the powerpoint presentation.

72

What does the complement cascade result in?

1) activation of the membrane attack complex (MAC) on the pathogen leading to perforations and lysis.

2) Production of opsonins, which are coatings that make the antigens more palatable to phagocytes.

3) Release of chemotactic agents (chemokines) which attract phagocytes (chemotaxis) to the areas of infection or inflammation.

73

The complement cascade results in the production of opsonins. What are opsonins?

Opsonins are coatings that make the antigens more palatable to phagocytes.

74

What is the parenchyma of a lymph node?

The parenchyma consists of the cells that typically pack areas of the lymphoid organ:
> mostly lymphocytes

75

What is the stroma of a lymph node?

The stroma consists mostly of reticular fibers and cells, including undifferentiated cells and fixed and free macrophages.

76

What is the hilus of a lymph node?

Where vessels enter and exit the lymph node.

*efferent lymphatic vessels as well as arteries and veins enter through the hilus

*afferent lymphatic vessels enter the convex side of the node.

77

What kind of tissue does the capsule of the lymph node consist of?

Dense Collagen Fibers

Some Elastic Fibers

Smooth Muscle Fibers

78

Where do afferent lymphatic vessels enter the lymph node?

Afferent lymphatic vessels enter the convex side of the node.

79

Where do efferent lymphatic vessel, veins, and arteries enter the lymph node?

Efferent lymphatic vessels as well as arteries and veins enter through the hilus.

80

True or False:

Trabeculae extend down in to the parenchyma for the capsule of a lymph node.

TRUE

81

What kind of cells does the follicles of lymph nodes contain?

B-cells

Follicular Dendritic Cells

Migrating Dendritic Cells

82

What does primary follicles lack that secondary follicles do not lack?

Primary follicles lack a mantle and a germinal center.

Secondary follicles do NOT lack a mantle and a germinal center.

83

Are lymph follicles (nodules) found in the outer cortex or the deep (inner) cortex?

Outer Cortex

84

The inner cortex contains what type of cells?

Contains T Helper Cells and Macrophages

85

In which part of the cortex is the high endothelial venules (HEVs) located? Also, what are HEVs?

The high endothelial venules are located in the deep (inner) cortex.

The high endothelial venules are a port of entry for circulating differentiated lymphocytes to seed lymph node.

86

The outer part of the cortex is bone marrow mediated and consists of B cells, unlike the inner cortex that contains T helper cells.

What Dr. Anderson Said in Class

87

What makes up the medulla of the lymph node?

irregular arrangement of loose medullary sinuses and dense medullary cords.

>sinuses are lined with macrophages
>cords consist of blood vessels, lymphoblasts and plasma cells

88

What kind of cells line the loose medullary sinuses of the medulla in the lymph node?

sinuses are lined with macrophages

89

What does the dense medullary cords of the medulla in the lymph node contain?

Cords consist of blood vessels, lymphoblasts, and plasma cells.

90

Where is the site of lymphocyte reentry into the lymph stream?

Medulla of the Lymph Node

91

A lymphatic follicle consists of a germinal center in which activated B cells proliferate. Proliferation occurs after B cells have activated by what type of cell?

Helper T-cells

*helper T cells are present in the inner cortex of the lymph node

92

Macrophages phagocytose apoptotic B cells with low affinity surface immunoglobulin (Ig). B cells with high affinity surface Ig migrate to the medullary cords and differentiate into short lived plasma cells that secrete which two antibodies?

IgM and IgG

Plasma cells secret IgM and IgG into the lymph, leaving the lymph node.