Lymphatic Organs Flashcards
(19 cards)
SPLEEN
Which three areas can the white pulp be divided in?
(and are they B- or T-dependent?)
- Periarteriolar lymphatic sheath (PALS) –> T-dependent
- Splenic nodules (Malpighien nodules or follicles) –> B-dependent
- Marginal zone –> B-dependent
SPLEEN
How can we differentiate between red and white pulp ?
H&E staining:
white pulp is strongly basophilic because of the densely packed lymphocytes. So it’s dark blue. The red pulp is lighter stained
SPLEEN
What forms the framework?
Reticular connective tissue (reticular fibers and reticulum cells)
SPLEEN
What staining method can we use to differentiate between localization of splenic B- and T-lymphocytes?
With Immunocytochemistry & H
LYPMH NODE
what structures can we find in the cortex?
- Lymphatic follicles (primary and secondary)
contain mostly B-lymphocytes (B-dependent area) - Interfollicular areas - contains mostly T-lymphocytes (T-dependent area)
- Paracortex: Free of follicles (T-dependent)
LYMPH NODE
What structures can we find in the medulla?
- Darker stained medullary cords
- Lighter stained medullary sinuses
- Numerous plasmacells (B-dependent area)
LYMPH NODE
What forms the framework?
Reticular connective tissue (reticulum cells and reticular fibers)
The reticulum cells have larger and lightly stained nuclei compared to the lymphocytes. They are stellate shaped.
SEEN IN SLIDE WITH TOLUIDINE BLUE STAINING
LYMPH NODE
What are the wall of the postcapillary venules in the region of the paracortex called?
And how do the cells look like?
The wall is lined by high endothelial cells, and are called high endothelial venules (HEV)
The cells are cuboidal with round pale nuclei
LYMPH NODE
What structures can be identified with Toluidine blue?
And where are they located?
- Plasma cells (medullary cords)
- Reticulum cells (Sinuses)
- High endothelial cells HEV (Paracortex)
- Tingible body macrophages (germinal center)
- Lymphoblasts (germinal center)
LYMPH NODE
Why are the germinal centers lighter stained?
Because the B-lymphoblasts have larger cytoplasm and less condensed nucleus
LYMPH NODE
- Where are the Macrophages located?
- Where are the Mast cells located?
- Macrophages: In the germinal centers of secondary follicles
- Mast cells: In the loose connective tissue surrounding the lymph nodes. Some mast cells are also seen in the parenchyme of the lymph node
PALATINE TONSIL
What epithelium forms the deep branching crypts?
Stratified squamous nonkeratinized epithelium
PALATINE TONSIL
What surrounds the palatine tonsils?
connective tissue capsule.
around this connective tissue capsule skeltal muscle and small mixed glands may be present in the section
PALATINE TONSIL
How can we differentiate between the T- and B-cells?
The T- and B-lymphocytes have different membrane proteins. Using immunocytochemical reactions against some of these proteins we can differentiate between them.
On slide no. 42:
Two sections
1. B-lymphocytes are shown by an antibody against the protein CD3
2. T-lymphocytes are shown by an antibody against the protein CD20
PALATINE TONSIL
How can we differentiate between the T- and B-lymphocytes?
Using immunocytochemical reaction, visualizing it with reddish-brown chromogen!
–> The positive structures are stained Reddish-brown
T-lymphocytes:
Are mainly in the interfollicular area
B-lymphocytes:
Mainly found in the lymphatic nodules. Also more numerous..
LINGUAL TONSIL
How can we identify the lingual tonsil?
- very short crypts
- a special feature is that the excretory ducts of the mucous glands situated under the lymphatic tissue drains into the base of the crypts
- The lymphatic tissue occupies a quite narrow band under the surface epithelium
- NO connective tissue capsule can be observed!!
Also seen structures:
- Skeletal muscle fibers
- Mucous glands
- Connective tissue of the tongue
PHARYNGEAL TONSIL
What kind of epithelium?
What other structures can we find?
Epithelium:
Pseudostratified ciliated columnar epithelium
- contains a few goblet cells
Other structures:
- thin connective tissue capsule
- Not very deep crypts
THYMUS (lymphatic)
What do we find in this slide?
- Thin connective tissue capsule
- trabeculae dividing the lymphatic tissue into LOBULES (not true lobules, but look like)
- Cortex (darker) and Medulla (lighter)
- Framework: Epithelial reticulum
- Hassal’s bodies (Thymic corpsules)
Also note: Macrophages and absence of lymphatic nodules.
THYMUS (involuted, fatty)
What can we find in this slide?
Mainly adipose tissue, and some lymphatic tissue islands displaying Hassal’s bodies
