Histology LAB. 3Lymphatic Tissue and the Immune System
Contains of this LAB.
Lymph node (MH 076 )
Tonsil of Human (MH S276 )
Spleen of human (MHS212 )
Thymus gland (MH 079 )
Edited by F ahad A.Mosul Medical College 2018 -2019 2th stage
Get it fromwww.muhadharaty.com
This copy is used to study tissue s with Histology Guide websiteto get a better result and a deeper understanding .
Do not hesitate to ask the doctors of the histology branch .
1 - Lymph nodeCapsule
enclosing the node
It's the inner region of the node
All the spherical clusters
Remember lighter center of
nodule s called germinal center
It's connective tissue
that extends inward from
7 Lymphatics at hilus
Medullary SinusesIntervening spaces in which
Notes StructureDense connective tissue enclosing the node.
- contains of :-
1- Subcapsular Sinus - space underneath the capsule that receives
lymph from afferent lymphatic vessels .
2- Trabeculae - connective tissue that extends inward from the
3- Trabecular Sinuses - spaces alongside trabeculae in which lymph
flows from the subcapsular sinus into the cortex .
Outer region of the node .
- contains of :-
with lighter Nodules have ( region adjacent to the capsule - Outer Cortex -1
) germinal center called center
2- Inner Cortex - (paracotex ) region between the outer cortex and the medulla
that is free of nodules.
Most inner part of the node .
contains of :- -
1- Medullary Cords
2- Medullary Sinuses - intervening spaces in which lymph flows
MH 076 VS Code – .com guide istology HLymph Node
ال تقسيم odulesN1- Primary nodules هي nodules التي تحتوي germinal center
2- Secondary nodules هي nodules التي ال تحتوي germinal center
3- white pulp ال هي nodules التي تحتوي على Central arteries و germinal center
وتوجد في spleen
Remember lighter center of nodule s called germinal center
2 - TonsilEpithelial lining
TYPE: s tratified Squamous
Non -Keratinized Epithelium
Spherical clusters الحظ
It's lighter center of nodules الحظ
It's Granules dispersed "lymph cell "الحظ
Notes StructureType of it Stratified Squamous Non -Keratinized Epithelium - covers
the numerous nodules that compromise the tonsil .
Infoldings of the epithelium into the underlying connective tissue. Crypts
spherical aggregations of lymphocytes ( have germinal centers ) Lymph Nodules
pass through the epithelium in areas of inflammation . Lymphocytes
Tonsil on Histologyguide.com76 2 S MH VS Code – Histologyguide.com
3 – SpleenCapsule
Enclosing the organ
Connective tissue that extends inward Blood vessels
Central arteriesRegular circle in nodule
It's Granules dispersed "lymph cell " الحظ
Red pulp االساليد ارضية هي و
Splen ic nodules
Notes StructureDense connective tissue enclosing the organ . Capsule
connective tissue that extends inward from the Trabeculae
Composed of lymphatic tissue.
It appears basophilic due to the large number of nuclei
Clusters of B lymphocytes located on central arterioles.
They usually contain a germinal center of activated B lymphocytes
branches of trabecular arteries . Central Arterioles
Filters and degrades red blood cells (RBCs).
It appears eosinophilic due to the large number of RBCs
vascular spaces Splenic Sinusoids
Spleen on Histologyguide.com212 S MH VS Code – Histologyguide.com
4 - Thymus (for adult)Hassel's Corpuscle
"nd & 2 st It have nodule "1
Small nuclei of condensed chromatin.
تقسم النسيج لفصوص
4- Thymus (Neonatal)Hassel's Corpuscle
LymphocytesSmall nuclei of condensed chromatin.
Notes Structurethin connective tissue surrounding the thymus that extends inward
as trabeculae to form incomplete lobules.
Adult = nner, lighter region of large lymphocytes. Cortex
Neonatal = outer darker, region of small lymphocytes.
It have -1- T-Lymphocytes
2- Epithelial Reticular Cells
inner, lighter region of larger lymphocytes.
Have " Hassel's Corpuscle "
Hassel's Corpuscle = closely packed, concentrically arrangedepithelial reticular cells.
Thymus on Histologyguide.com079 MH VS Code – Histologyguide.com
Questions //Question : Where else do you find tonsils in the oral cavity?
1 – Palatine tonsils
2 – Pharyngeal tonsils
3 – Lingual tonsil
Question : What is the function of tonsils?
They are the immune system's first line of defense against ingested or inhaled foreign
Play role in immunity of the body because they contain B&T - lymphocytes thus they are
important especially in children .
Discuss the effects of removing the tonsils .
(A very common procedure not so long ago!)
Question : What is happening to the thymus gland with increasing age?Is it still functional in the adult?
Task : List the major immune cells and their functions