Histology Practical
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24) Lymph node
25) Thymus
26) Spleen
27) Palatine Tonsil
28) Root of Tounge
General Information about lymphatic tissue:
Red bone marrow
Thymus
Primary Lymphatic organs. All others are
secondary.
What is the stroma of the Network? Reticular fibers! Native lymphocytes are released from primary
lymphatic organs but have to be immune competent
Only secondary lymphatic Organs posses lymphatic follicles
B-Cells = immunoglobines require B-Cell Receptors (BCR) therefore lymphatic follicles occur
function: keeping the own antigen environment, eliminating the foreign substances/antigens
lymphoid tissue lymphoid organs: primary (red bone marrow, thymus): development of lymphocytes
secondrary(lymph node, spleen, tonsils, Peyer s patches, appendix): mature lymphocytes can be
found here
basic tissue: lymphoreticular- reticular connective tissue, reticular fibers, reticular cells; thymus:
epithelial reticular cells
main cell types: lymphocytes, macrophages, dendritic cells, endothelial cells
Lymphoid follicles
unit of the lymphoid tissue
round, oval structure, many lymphocytes
primary: dark, ruond, little lymphocytes, intrauterine
secondary: bigger (200-400 m), originating from the primary,
in the middle: light area- germinal center (centroblasts, centrocytes, FDC), peripheral: cap zone
24) Lymph node
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Mantle zone
Lymphatic follicles
Cortex (inner / outer zone)
Anastomosing network of lymphoids
Medulla:
o Medullary cord (dark)
o Medullary sinuses (pale)
Cortex: inner B-Cell Zone
Medulla: B-Cell zone
along the course of lymphatic vessels
bean-shaped, encapsulated organs
afferent lymphatic vessels efferent lymphatic vessels
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
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connective tissue capsule trabeculae hilus
among trabeculae: reticular connective tissue
cortex: lymphoid follicles (B dep. zone)
paracortex: no lymphoid nodules (T dep. zone)
medulla: medullary lymphoid sinuses, medullary cords
marginal sinus intermediate sinus medullary
sinus efferent lymphatic vessels (hilus)
Lymph node:
Lymph node Reticulin fibers:
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
CD (cluster differentiation) marker: CD19 & CD20: B-Cells
 CD3: all
 CD4: helper
 CD8: cytotoxic
25) Thymus
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Lobulated organ, it has septa which separate the lobules
Cortex is darker
Medulla is paler
Lymphocytes wander from cortex to medulla
In the Medulla there are larger cells
No incoming just outgoing.
Hassals corpuscle
o Pinkish mass in center
o Can only be found in Medulla
o Has no function for thymus
epithelial, lymphatic, adipose form during life
2 lobes+ capsule lobules
cortex: peripheral, darker, thymocytes, macrophages, epithelial reticulum cells
medulla: central, lighter, more epithelial reticulum cells,
Hassal-corpuscules (eosinophil,concentrically arranged,flattened epithelial cells with
keratohyalingranules), neuroendocrine cells, myoid (Hammar)cells
no lymph follicles
function: mature and differentiation of T lymphocytes
blood-thymus barrier: pericytes, capillary basal lamina, basal lamina of the epithelial reticular
cell, cells of the endothelium, epithelial reticular cells
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
26) Spleen
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Main color pinkish because of the erythrocytes but there are also small bluish spots
intraperitoneal organ
connective tissue capsule trabeculae parenchyma (pulp)
red pulp (80%), white pulp (20%)
reticular connective tissue, reticulum cells, reticular fibers
red pulp: Billroth s cords, sinuses
white pulp: PALS (A. centralis- T dep. zone), lymhoid follicles
Malpighi (B dependent), marginal zone
open and closed circulation
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
27) Palatine tonsil
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lymhoid tissue in the mucosa
Waldeyer s lymphatic ring:
o pharyngeal tonsils
o palatine tonsils
o tubal tonsils
o lingual tonsils
 tonsillary epithelium+ lymhoid tissue
(lymphoreticular connective tissue)
 tubal and pharyngeal t.: ciliated
pseudostratified epithelium with
goblet cells
 lingual and palatine t.: stratified
squamos nonkeratinized epithelium
 epithelium crypts: lingual t.- shallow, wide// palatine t.: narrow, deep
 lingual t.: seromucous glands crypts, strited muscle fibers
 follicles (B dep.), interfollicular area (T dep.)
 epithelium is often infiltrated with lymphocytes
Palatine tonsil
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
Pharyngeal tonsil
Lingual tonsil
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)
Copyright by Matthias Heyner Based on the Histology practical from E. Dobo et. al at the University
of Szeged videos by WashingtonDeceit (www.youtube.com/user/WashingtonDecit)