Lymphatic Tissue Flashcards
1
Q
What are the two primary lymphatic tissues? What characteristic distinguishes them?
A
Bone marrow
Thymus
Site of development and maturation of lymphocytes into immunocompetent cells
2
Q
What are the three secondary lymphatic tissues?
A
- Lymph nodes
- Mucosa-associated lymphatic tissue (MALT)
- Spleen
3
Q
What are the four subtypes of mucosa-associated lymphatic tissue?
A
- GALT (gut associated)
- BALT (bronchus)
- GU tract
- Tonsils
4
Q
What is the defining characteristic of secondary lymphatic tissue?
A
Site of formation of immunological defense against antigens or pathogens
Confrontation with antigens or pathogens occurs here
5
Q
What part of the lymph system filters lymph?
A
Lymph nodes
6
Q
What part of the lymph system filters blood??
A
Spleen
7
Q
What part of the lymph system acts as surveillance?
A
MALT
8
Q
Where does confrontation of antigens occur?
A
In secondary lymphatic tissues
9
Q
Where is GALT found?
A
In the lamina propria of the intestines
10
Q
Where are the mucous-associated lymphatic tissues found within the body?
A
Sprinkled in loose CT as part of another organ, usually in the lamina propria
11
Q
What type of cells are present in lymphatic tissue?
A
Lymphocytes
Monocytes
Macrophages
Plasma cells
12
Q
What type of fibers are present in lymphatic tissue?
A
Reticular fibers
13
Q
What are the histological characterisitcs of primary lymphatic nodules?
A
appears homogenous throughout, has mostly small lymphocytes
14
Q
What are the histological characterisitcs of secondary lymphatic nodules?
A
Has a corona zone and a germinal center
15
Q
What distinguishes between primary and secondary lumphatic nodules?
A
Appearance
16
Q
What is the corona zone in secondary lymphatic tissue?
A
the outer, dark-staining zone, containing mature lymphocytes
17
Q
What is the germinal center of secondary lymphatic nodules?
A
The inner, light-straining zone containing immature lymphocytes
18
Q
Encounter with an antigen has what effect on the germinal centers of secondary lymphocytes?
A
Causes the center to swell
19
Q
What helps suspend cells in primary lymphatic nodules?
A
Reticular fibers
20
Q
When there is a clear differentiation in the mantle zone and the germinal center of secondary lymphatic nodules, what has occurred?
A
Anitgen is/was present
21
Q
What processes are taking place in the germinal center of secondary lymphatic nodules?
A
Mitosis
22
Q
What type of cells are in the mantle zone of secondary lymphatic nodules?
A
Mature lymphocytes
23
Q
What are the two forms that lymphatic nodules may appear as? How long do each last (relatively)?
A
Solitary lymph nodes are short lived
Aggregates of lymph nodes are permanent
24
Q
What are the four examples of lymphatic node aggregates that were discussed in class?
A
Peyer’s patches
Lymphatic tissue in appendix
BALT in respiratory tract
Lymphatic nodules in the tonsils lymph nodes, and spleen
25
What are Peyer's patches? Where are they found? What do they contain?
Lymph node aggregates in the ileum that contains B and T lymphocytes
26
What do the lymphatic tissue in the appendix contain? Where are these found in the layers of the tissue?
Consists of permanent aggregations of lymphatic nodules
| in the lamina propria and the submucosa of the appendix
27
The lymphatic nodules present in the tonsils, lymph nodes, and spleen are of what type?
Lymphatic aggregates
28
What type of lymph tissue is found in the appendix?
Primary lymphatic nodule aggregates
29
The pharyngeal, palatine, and lingual tonsils are aggregations of what? What cells do they contain?
Lymphatic nodules, containing B lymphocytes
30
What is characteristic of the CT of the tonsils? What is the purpose of this?
Thay have partial / incomplete CT capsule which sends septa into the interior of the tonsil.
Capsule may provide some protection from spread of tonsilar infections
31
What is the epithelial type that surround the pharyengeal tonsils?
Pseudostratified columnar
32
What is the epithelial type that surround the lingual tonsils?
Stratified squamous (non-keratinized)
33
What is the epithelial type that surround the palatine tonsils? What infiltrates this?
Stratified squamous (non-keratinized), infiltrated by B lymphocytes
34
What are the epithelial lined pits that are present in palatine tonsils?
Crypts
35
What surrounds the palatine tonsils on the non-luminal side?
Cap
36
What do the palatine tonsils contain? What is the purpose of these?
lymphatic nodules where B-lymphocytes are produced
37
What type of epithelium covers the pharyngeal tonsil? What specialization does the epithelium have?
Pseudostratified columnar with cilia
38
What forms the white exudate found in viral tonsillitis?
WBCs
39
Adenoid tonsils is to (insert word here) as pharyngeal tonsils is to crypts.
Pleats
40
What are the only organs that are located along the path of a lymphatic vessel?
Lymph nodes
41
What is the function of lymph nodes?
Filter lymph prior to being passed on to the bloodstream
42
What covers lymph nodes? What is this made of?
A capsule formed by dense CT
43
What are trabeculae in lymph nodes? What is located here?
CT septa that extend from into the lymph node carrying blood vessels and nerves?
44
What carries blood vessels and nerves into lymph nodes?
Trabeculae
45
What is the site where blood vessel and efferent lymphatic vessel leave the lymph node?
Hilum
46
What forms the inner part of the lymph node?
Cortex + Medulla
47
What are the vessels that bring in lymph/blood to the lymph node? What specialization do these have?
Afferent lymph vessels that have valves
48
What are the three sinuses of lymph nodes?
Subcapsular
Trabecular
Medullary
49
Where are subscapular sinuses located in lymph nodes? What do these sinuses drain into?
Just beneath the capsule, and drain into trabeculae
50
Where are the trabecular sinuses located, and where do they drain?
Found separating the lymphatic nodules from trabeculae, and drain into medullary sinuses
51
What two cells types are found within trabecular sinuses, and what are their function?
Endothelial cells which act as gates for lymph and reticular cells that serve as anchoring points for macrophages
52
All lymph sinuses are lined by what type of cells?
Macrophages
53
What is the last sinuses in lymph nodes that are found in the deepest layer, and are wide and tortuous?
Medullary sinuses
54
What do the medullary sinuses drain into?
Efferent lymph vessels
55
What is the framework that suspends cells in the lymph node made from? What cells make it?
Reticular fibers from reticulocytes
56
What is the flow of lymph through a lymph node?
1. Afferent lymphatic vessels (numerous, penetrate capsule, have valves)
2. Subcapsular (cortical) sinus (located between capsule and parenchyma)
3. Trabecular sinuses
4. Medullary sinuses – interconnected lymphatic channels (wide, tortuous)
5. Efferent lymphatic vessels (at hilum, have valves)
57
What are the three types of cells that are found in the reticular tissue of lymph nodes?
Reticulocytes
Dendritic cells
Macrophages
Follicular dendritic cells
58
What is the function of reticulocytes?
Synthesize collagen III (reticular fibers)
59
What is the function of the dendritic cells in lymph tissue?
Anitgen presenting cells that monitor for foreign substances
60
What is the function of the macrophages found in lymphatic tissue?
Phagocytic
61
What is the function of the follicular dendritic cells of the reticular tissue?
Bind antigen complexes
62
What is the parenchyma part of lymphatic cells?
The cellular part
63
What are the three components of the parenchyma cells?
Cortex
Paracortex
Medulla
64
What is the function of the dendritic recticular cells that are a part of the cortex of lymph nodes?
bind newly synthesized immunoglobulin and when these cells re-encounter the same antigen, they bind it and present it to the B- and T-lymphocytes
65
What does the paracortex part of lymph nodes contain?
1. T-lymphocytes
| 2.
66
Does the cortex part of lymph tissue have more or less cells than the medulla part?
More
67
What is the thymus-dependent part of the lymph node? Why?
The paracortex, because it receives B and T lymphocytes from the blood via high endothelial venules
68
What is the function of the high endothelial venules of lymph nodes?
Receive 90% of the B and T lymphocytes from the blood produced by the thymus
69
What are the two routes into lymph nodes that B and T lymphocytes may take?
Through afferent lymph vessel (10%)
High endothelial venules
70
What is contained in the Medullary cords of the medulla of lymph nodes?
Reticular cells/fibers
Lymphocytes
Plasma cells
(Most cells associated with lymph nodes)
71
Are lymphatic nodules primary or secondary? Permanent or temporary?
Secondary, thus permanent
72
What is the blood supply/flow of lymph nodes?
1. Hilum
2. trabeculae
3. medulla
4. medullary cords
5. Form capillaries
6. empty into post capillary venules
73
Where are B-lymphocytes primarily found in lymph nodes?
Cortex
74
Where are T-lymphocytes primarily found in lymph nodes?
Paracortex
75
Where do the t-lymphocytes that are present in lymph nodes ultimately come from?
Thymus
76
Where are the high endothelial venules found in the lymph node?
In the paracortex
77
What is the epithelium that lines high endothelial venules?
simple cuboidal to columnar
78
What happens to B and T lymphocytes when the leave the high endothelial venules?
B go to the cortex
| T go the the paracortex
79
What are medullary cords?
Clumps of cells that contain plasma cells, dendritic cells, macrophages
80
Are the sinuses of lymph nodes empty spaces?
No--filled with reticular cells lymphocytes
81
Do the plasma cells leave the lymph node, or just their antibodies?
Just the antibodies
82
Where to T lymphocytes originate from? Where do they go to after that?
Bone marrow, go to thymus where they mature
83
How many lobes are they to the thymus?
2
84
What is the capsule of the thymus made of?
Dense, irregular collagenous CT
85
What partitions the thymus to form thymic lobules?
Trabeculae
86
What are the two compartments of each thymic lobule?
cortex and medulla
87
Are the lobules of the thymus completely separate?
No
88
What does the capsule of the thymus contain?
Blood vessels, efferent lymphatic vessels and nerves
89
What does the CT of the thymus contain?
Collagen, fibroblasts, plasma cells, granulocytes, lymphocytes
mast cells
adipose cells
Macrophages
90
True or false: the medulla of each thymic lobule is distinct and separate?
False--all are connected
91
What happens as t-lymphocytes migrate through the cortex to the medulla?
Mature
92
What is the framework for the thymus?
Epithelial retciular cells
93
What are type I reticular cells?
Cells that forma a seal around the cortex of the thymus, separating it from the CT capsule and trabeculae
94
What are the junctions between type I reticular cells?
Occludens (tight) junctions
95
What are type II epithelioreticular cells?
Are cells that branch in a stellate fashion to form a meshwork in the mid cortex
Functions as "teachers"
96
What are type II epithelioreticular cells connected by?
Desmosomes
97
What are type III epithelioreticular cells?
Cells that reside deep in the cortex of the thymus, and form the corticomedullary junction, forming a seal between the cortex and the medulla
98
What common function do all three types of epithelial reticular cells have?
Protection the thymus and isolate it from antigens
99
Which type of epithelioreticular cells form the blood-thymus barrier? What are the other components of this? (4)
1. Type I cells
2. Basal lamina
3. Cortical capillary endothelium
4. Macrophages
100
Where are the first four types of epithelioreticular cells found?
I = outer
II = in the cortex
III and IV = at the medullary and paracortex junction
101
What are type IV epithelial reticular cells? What do they do? Where are they found?
cells are associated with Type III cells and participate in the establishment of a "barrier" at the corticomedullary junction
102
What are type V epithelial reticular cells? What do they do? Where are they found?
form the meshwork / cytoreticulum (framework) of the medulla
103
What are type VI epithelial reticular cells? What do they do? Where are they found?
form thymic corpuscles called Hassall's corpuscles - concentric, eosinophilic, whorls, unique to the thymic medulla. They exhibit keratinization
104
What are Hasall's corpuscles? Do they stain darker or lighter than the surrounding tissue?
Areas formed by type VI epithelioreticular cells that contain mature T-lymphocytes
Stain lighter
105
Where do immuocompetent T lymphocytes leave the thymus? Where do they go?
Via postcapillary venules to go to the paracortex of lymph nodes, PALS of the spleen, GALT, and BALT
106
Where is the only place that Hasall's corpusles are found?
Thymus
107
What is DiGeorge's syndrome?
Developmental disorder where the thymus does not develop, thus causing an inability to produce T lymphocytes.
Death = by infection
108
Where is the major site of T and B lymphocytes proliferation?
Spleen
109
What is the white pulp of the spleen made of?
PALS
| Splenic nodules
110
What suspends the red pulp?
Reticular fibers
111
What are the two major components of the spleen?
Red and white pulp
112
What is contained in the Red pulp of the spleen?
Splenic sinuses
| Spelnic cords
113
What is the function of splenic sinuses? What are they lined by
Are lined by endothelial cells, with wide intercellular spaces allowing blood cells to pass in and out of the sinuses
Drain into pulp veins which in turn drain into trabecular veins
114
What is the artery that enters the spleen at its hilum? What does it give rise to once inside?
Splenic artery, which gives rise to trabecular arteries
115
What happens to the trabecular arteries once they enter they leave the CT of the trabeculae?
Loose their tunica adventitia, and are infiltrated with T-lymphocytes
116
What is the periarteral sheath?
T-lymphocyte covered central artery in the spleen
117
What are the arteries that lose their T-lymphocyte sheath and penetrate into the red pulp?
Penicullar arterioles, then arterial capillaries
118
Where do the arterial capillaries and sheathed capillaries in the spleen drain into?
Splenic sinuses
119
What is the path of blood flow in the spleen? (7)
1. Spenic artery
2. Trabecular arteries
3. PALS, central artery
4. Penicillar arteries
5. Arteriole capillaries
6. Sheathed capillaries
7. Splenic sinuses
120
What color does white pulp in the spleen stain?
Basophilic Blue
121
What is the part of the spleen that contains T-lymphocytes?
White pulp
122
What are splenic nodules? What do they contain? Where are they found
Lymphatic nodules in the white pulp that contain B lymphocytes
123
What is the marginal zone of the spleen?
Between the red and white pulp
124
What are the two components of the red pulp? What does it stain with?
1. Spelcni cords
2. Splenic sinuses
Eosinophilic
125
What are the splenic cords that make up the red pulp of the spleen?
They are irregular branchig cords of tissue consisting of reticular fibers/cells, with the spaces between fibers filled with filtered blood
126
What are the splenic sinus of the red pulp in the spleen? What are their function?
Sinuses lined by enothelial cells.
Drain blood into pulp veins, which drain into trabecular veins
