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Histology Sem 3 > Lymph > Flashcards

Flashcards in Lymph Deck (70)
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1
Q

Effector cells of the lymphatic system

A

Lymphocytes

2
Q

Provides physical support for lymphocytes

A

Supporting cells: stromal cells, monocytes/macrpphages, polymorphomuclear leukocytes, dendritic cells

3
Q

Supporting cells that form a loose meshwork that creates a suitable environmetn for lymphocytes

A

Stromal cells

4
Q

Supporting cells that assist with antigen presentation and regulation of immune response

A

Monocytes/macrophages, polymorphonuclear leukocytes, and dendritic cells

5
Q

Non-specific type of immunity that does not require exposure to an antigen

A

Innate immunity

6
Q

Represents innate immunity

A

Physical or chemical barriers, phagocytic and natural killer cells

7
Q

Specific type of immunity and develops after the exposure to an entigen

A

Adaptive immunity

8
Q

2 types of adaptive immune responses

A

Humoral and cell-mediated

9
Q

Mediated by antibodies that act on invading agents. Produced by B cells and plasma cells

A

Humoral immunity

10
Q

Mediated by Tc Cells, NK cells, monocytes/macrophages, PNMs

A

Cell-mediated immunity

11
Q

Primary lymphatic organ

A

Bone marrow and Thymus

12
Q

Type of tissue in bone marrow

A

Reticular connective tissue

13
Q

Contents of cords of cells

A

Blood cell precursors, mature blood cells, adipocytes, stromal cells

14
Q

General structure of bone marrow

A

Hemopoietic cords supported by reticular fibers

15
Q

Types of stromal cells

A

Fibroblasts and macrophages

16
Q

What does the thymus develop from?

A

3rd and 4th branchial pharyngeal pouch

17
Q

Most abundant cell of the thymus

A

T cell

18
Q

Supports lymphcytes that provides a framework for the developing t cells

A

Epithelioreticular cells

19
Q

Structure of epithelioreticular cells

A

True epithelial cells, connected by occuding junctions and desmosomes forming a sytoreticulum, but do not decrete reticular fibers

20
Q

Phagocytose the T cells that do not fulfill thymus education requirements

A

Macrophages

21
Q

Connective tissue extends into the parenchyma as thin struts form what?

A

Trabeculae

22
Q

Characterizes the cortex of the thymus

A

Densely packed lymphocytes that are the least differentiated

23
Q

Characterizes the medulla of the thymus

A

Lighter-staining, have Hassal’s corpuscles that contain a keratin pearl

24
Q

Prevents antigens from escaping cortical capillaries into the thymus cortex

A

Blood-thymus barrier

25
Q

3 mechanisms that make up the blood-thymus barrier

A

Continuous capillaries (tight junctions), perivascular connective tissue (contains macrophages), Epithelioreticular cells (form occluding junctions around the capillaries)

26
Q

3 stages od T cell education

A

Double-negative stages, Double-positive stage, single positive selection

27
Q

Stage that occurs in the thymuc cortex, T cells have no CD4 or CD8, and only have CD2 and CD7 on surface

A

Double-negative stage

28
Q

Stage that occurs in the thymic cortex, T cells express TCR, CD3, CD4 and CD8. T cells are presented with both self-MHC and self/foreign antigens and must recognize both

A

Double-positive stage

29
Q

Stage in thymic medulla where the double-positive cells recognize self-antigen presented by self-MHC are eliminated

A

Single-positive stage

30
Q

Secondary lymphatic organs

A

MALT, GALT, BALT

31
Q

Lymph tissue that does not have a capsule and consists of loosely arranged immune cells

A

Diffuse lymphoid tissue

32
Q

Spherical structures scattered throughout the lamina propria of the GI tract

A

Lymphoid follicles (composed mostly of B Cells)

33
Q

Express receptors for soluble immunoglobins

A

Follicular dendritic cells

34
Q

Dividing of lymphocytes are what type of follicles?

A

Secondary

35
Q

Portion of the primary follicle that contains large, activated immature lymphocytes that are undergoing mitoses

A

Germinal center

36
Q

Portion of primary follicle that contains small lymphocytes that arround the germinal center

A

Mantle

37
Q

secondary lymph found in the ileum and appendix

A

Aggregated lymphoid follicles

38
Q

Lymph in the lamina propria of the ileum

A

Peyer’s patches

39
Q

Ring of lymph tissue at the entrance of the oropharynx

A

Tonsils

40
Q

3 types of tonsils

A

Palatine, pharyngeal, smaller tonsils (lingual and tubal)

41
Q

Type of tissue covering the palatine tonsils and what is forms

A

Non-keratinized stratified squamous epithelium that forms tonsillar crypts

42
Q

Where are B and T cells stored in the tonsillar crypts?

A

Lymphoid follicles (B cells) and spaces between the follicles (T cells)

43
Q

How do the lymphocytes exit the palatine tonsil?

A

High-endothelial venules

44
Q

Located beneath the capsule of the lymph node

A

Subcapsular sinus

45
Q

Projections from the lymph node capsule into the parenchyma

A

Trabeculae (with trabecular sinuses within them)

46
Q

What cells are contained in the outer cortex of the lymph node?

A

B cells

47
Q

What cells are contained in the paracortex of the lymph node?

A

T cells

48
Q

Portion of the lymph node medulla that contains lymphocytes, plasma cells, macrophages, dendritic cells

A

Medullary cords

49
Q

Recieves lymph from the trabecular sinuses and converage near the hilum where they drain into the efferent lymphatic vessel

A

Medullary sinuses

50
Q

Allows for filtration of lymph and connects the lymphatic channels

A

Sinuses

51
Q

Contained in the lymph sinuses

A

Meshwork of crisscrossing reticular fibers and macrophage processes

52
Q

Drains into the efferent lymphatic vessel

A

Medullary sinuses

53
Q

Name of the postcapillary venules in lymph nodes and what are they lined with?

A

High endothelial venules are lined with cuboidal epithelium

54
Q

Expressed in high concentration in the HEVs

A

Water channels

55
Q

What do the specialized endothelial cells of HEVs have?

A

Receptors that signal both T and B cells to leave circulation and migrate into the lymph node

56
Q

Function of the lymph node

A

Phagocytosis and initiation of immune reponses

57
Q

Where are HEV’s usually found?

A

T cell region

58
Q

Purpose of the spleen?

A

Filters blood and reacts immunologically to blood-borne antigens

59
Q

Contents of spleen capsule

A

Regular fibroblasts and myofibroblasts, so spleen can be contracted

60
Q

Contents of the spleen pulp

A

White and red pulp

61
Q

2 major components of white pulp

A

Periarterial lymphatic sheath (mainly T cells) and Lymphoid follicles (B cells)

62
Q

Contents of red pulp

A

RBCs and splenic sinuses/cords

63
Q

Characteristic of splenic cords

A

Dense meshwork of reticular fibers, large number of RBCs, macrophages, lymphocytes, plasma cells, and granulocytes. Splenic macrophages phagocytose damaged RBCs here

64
Q

Receives blood that has been filtered thru the cords

A

Splenic sinuses

65
Q

Brings blood to the spleen then breaks into trabecular arteries

A

Splenic artery

66
Q

What artery is surrounded by PALS?

A

Central Artery

67
Q

Short straight vessels in the red pulp

A

Penicillar arterioles

68
Q

Arteries surrounded by a sheath of macrophages

A

Sheathed capillaries

69
Q

Type of circulation in the spleen

A

Open circulation

70
Q

Order of splenic veins

A

Splenic sinuses to pulp veins to trabecular veins to splenic veins