CHAPTER 6 - LYMPHOID ORGANS Flashcards
1
Q
LYMPHOID ORGANS
- Divided into two:
A
Primary and Secondary lymphoid organs
2
Q
- Main producers of lymphocytes (B cells and T cells)
A
Primary
3
Q
o Followed by release to the circulation
then to the secondary lymphoid organ (SLO)
A
Primary
4
Q
- Provide appropriate microenvironments or the development and maturation of lymphocytes
A
Primary
5
Q
- Thymus
A
Primary
6
Q
- Bone marrow
A
Primary
7
Q
- Site of maturation and site where lymphocytes can perform their main functions.
A
Secondary
8
Q
- Trap antigen from defined tissues or vascular spaces and are sites where mature lymphocytes can interact effectively with the antigen
A
Secondary
9
Q
o Tonsils, spleen (lymph nodes (Lymphatics and skin), Peyer’s patches, appendix, and mucosa- associated lymphoid tissue (MALT)
A
Secondary
10
Q
function as potential sites for contact with foreign antigen, and they increase the probability of an immune response.
A
Secondary
11
Q
- Adenoids
A
Secondary
12
Q
- Tonsils
A
Secondary
13
Q
- Lymph nodes
A
Secondary
14
Q
- Spleen
A
Secondary
15
Q
- Peyer’s Patches
A
Secondary
16
Q
- Appendix
A
Secondary
17
Q
- MALT
A
Secondary
18
Q
– lymphatics and skin
A
Lymph nodes
19
Q
– entry through circulation
A
Spleen
20
Q
– a specialized type of MALT and are located at the lower ileum of the intestinal tract
A
Peyer’s Patches
21
Q
- Largest tissue of the body (adult: 1300 to 1500g)
A
Bone Marrow
22
Q
Bone Marrow
- Two parts:
A
- Red marrow
- Yellow Marrow
23
Q
– produces blood cells
A
Red marrow
24
Q
– higher percentage; cannot produce HSC
but adipose/fat cells instead
A
Yellow Marrow
25
- Primary function: Primary source of pluripotent stem cells that give rise to all hematopoietic stem cells (HSC) that fives rise to other blood cells
Bone Marrow
26
- Major organ for B cell maturation (“B” cells = “B”one marrow) gives rise to the precursor cells of the thymic lymphocytes.
Bone Marrow
27
- common lymphoid progenitor
HSC
28
- common myeloid progenitor
HSC
29
– produced in the BM then undergo further maturation to a B cell (either released to the circulation or proceeds to SLO)
B cell progenitor
30
– produced in the BM then proceeds to the thymus for further maturation
T cell progenitor
31
- Center for antigen-independent lymphopoiesis (production of lymphocytes)
Bone Marrow
32
o Without the stimulus of an antigen
Bone Marrow
33
o Maturation does not end as B cells and T cells
Bone Marrow
34
= Plasma cell (can produce
Abs)
B cell + Ag
35
= memory B cell (remembers Ag encounter)
T cell + Ag
36
o Produce large numbers of B cells, each with unique
antigen receptors (antibodies) such that, overall, there is sufficient B cells diversity to recognize millions of microbial antigens in the environment.
Bone Marrow
37
- Same to the concept of Ab-diversity by Paul Ehrlich (Side Chain Theory)
Bone Marrow
38
- An Ag looks for a particular cell with a specific receptor to become an Ab
Bone Marrow
39
- To avoid autoimmunity (attacking of own cells due to overreactivity of B cells)
Eliminate B cells with antigen receptors having high affinity for self-molecules.
40
61-89% = (?)
T cells (Most abundant)
41
10-20% = (?)
B cells
42
- Primarily involved in adaptive/specific
immunity
T cells & B cells
43
22% =(?)
NK cells
44
- Neither B or T cells
NK cells
45
- Large Granular: Lymphocytes
NK cells
46
- Primarily involved in innate/natural
immunity
NK cells
47
– produced in the BM (+ T cell progenitor: thymus)
Thymocytes
48
– produced, matures and develops in the BM
B cells
49
– matures and develops in the thymus
T cells
50
- Site of T-cell development and maturation
Thymus
51
- Rearrangement of gene segments that encode T cell receptor
Thymus
52
- Flat bilobed organ above the heart
Thymus
53
- Each Lobe surrounded by a capsule and divided into lobules.
Thymus
54
Thymus
- Each lobule:
o Outer cortex
o Inner medulla
55
(?) : densely packed with immature T cells: thymocytes
Outer cortex
56
(?) : sparsely populated with thymocytes
Inner medulla
57
Function example:
o Ag enters the wound → trapped in the axillary lymph
nodes (kulani); filters the lymph
Lymph Nodes
58
- lined with macrophages, creating an ideal location for phagocytosis
Subcapsular sinus
59
Blast transformation – B cells become plasma cells that are capable of producing Ab
Germinal center
60
– B cells become plasma cells that are capable of producing Ab
Blast transformation
61
Cells: Macrophages, most of B cells, follicular dendritic cells
Cortex (outermost layer)
62
- Contains Naïve B cells (resting B cells)
Primary Follicles
63
o Has not encountered an Ag
Primary Follicles
64
- Consist of antigen-stimulated B cells
Secondary Follicles
65
- Has encountered an Ag
Secondary Follicles
66
The interior of a secondary follicle is known as the (?)
germinal center
67
Cells: Most T cells
Paracortex
68
- Space between cortex/follicles and medulla
Paracortex
69
- T lymphocytes are mainly localized in the (?).
paracortex
70
T lymphocytes are in close proximity to antigen-presenting cells called (?).
interdigitating cells
71
Cells: mostly macrophages, numerous plasma cells
Inner Medulla
72
The (?) is less densely populated but contains some T cells (in addition to B cells), macrophages, and numerous plasma cells.
medulla
73
Particulate antigens are removed as the fluid travels across the node from cortex to medulla.
Inner Medulla
74
The transit time through a lymph node is approximately 18 hours.
Inner Medulla
75
- If contact with antigen takes place, lymphocyte traffic shuts down due to the proliferation of activated cells.
Inner Medulla
76
- Accumulation of lymphocytes and other cells causes the lymph nodes to become enlarged, a condition known as (?) .
lymphadenopathy
77
- Recirculation of expanded numbers of lymphocytes then occurs
Inner Medulla
78
- Largest secondary lymphoid organ
Spleen
79
- It is located in the upper-left quadrant of the abdomen
Spleen
80
(?) : removal of the spleen
Splenectomy
81
o Increases risk of infection with encapsulated bacteria and severe malaria
Splenectomy
82
(?) :intraerythrocyticparasite
Plasmodium
83
Cells: Platelets, RBCs, WBCs
Red Pulp
84
- Responsible for apoptosis or programmed cell death
Red Pulp
85
Cells: WBCs
White Pulp
86
- Also known as the lymphoid tissue
White Pulp
87
- contains T cells
Periarteriolar Lymphoid Sheath (PALS)
88
- contains Naïve B cells (resting B cells)
Primary Follicles
89
- contains dendritic cells (best Ag presenting cells; traps antigen)
Marginal Zone
90
- Nasal
NALT
91
– lines the throat and nasal passages
Nasal
92
- Tonsils
NALT
93
- Gut
GALT
94
- Contains the Peyer’s patches
GALT
95
Liver
GALT
96
– specialized
epithelium and contains antigen presenting cells and
intraepithelial lymphocytes.
Peyer’s patches
97
- Bronchus
BALT
98
- Contains lymphoid aggregates and follicles along
main bronchi
BALT
99
Secondary lymphoid organs
Appendix
100
o Concentrate of lymphoid tissue
Appendix
101
o Produces IgA
Appendix
102
(?) : important in trapping Ags that enters the GIT
lymphoid tissue
103
(?) : helps in regulating the density and quality of the normal flora
IgA
104
- Almost the same as BALT
Cutaneous Associated Lymphoid Tissue (CALT)
105
- Found in the skin or epidermis
Cutaneous Associated Lymphoid Tissue (CALT)
106
- Most of these are T cells, which are uniquely positioned to
combat any antigens that enter through the skin.
Cutaneous Associated Lymphoid Tissue (CALT)
107
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