Upload
candra
View
62
Download
4
Tags:
Embed Size (px)
DESCRIPTION
Thymus and Spleen. The Spleen: What is it good for?. Filters blood Iron Retrieval RBC reserve Immune Response* Fetal Hematopoiesis. The ‘White’ Pulp. Appears basophilic on H&E and red on silver stain Site where immune response is mounted; formation of germinal centers - PowerPoint PPT Presentation
Citation preview
Thymus and Spleen
The Spleen: What is it good for?
1. Filters blood
2. Iron Retrieval
3. RBC reserve
4. Immune Response*
5. Fetal Hematopoiesis
The ‘White’ Pulp
• Appears basophilic on H&E and red on silver stain
• Site where immune response is mounted; formation of germinal centers
• Germinal centers with B cells and B cell derivatives push the ‘central artery’ off to the side
White Pulp Vasculature
• The central artery is found in the white pulp
• The central artery is surrounded by the PALS, which is T cells
• Penicilli branch from the central artery into the red pulp
White Pulp Vasculature
• The central artery is found in the white pulp
• The central artery is surrounded by the PALS, which is T cells
• Penicilli branch from the central artery into the red pulp
White Pulp Vasculature
• The central artery is found in the white pulp
• The central artery is surrounded by the PALS, which is T cells
• Penicilli branch from the central artery into the red pulp
Red Pulp Vasculature:
• Penicilli give rise to ellipsoids
• Ellipsoids are capillaries ensheathed by reticular cells and macrophages; their lumens are often occluded in histo sections
• Blood is filtered by macrophages through fenestrations in the sinusoids
Sinusoids
See how the basal lamina is interrupted; evident with both stains
Sinusoids
Lining of endothelial cells: apposed to one another, but remain separated
Macrophages extend their processes into the lumen of the sinusoid (you can see the remains of RBCs in macrophages)
The Red Pulp
• Appears Red on H&E
• Composed of sinusoids and Cords of Billroth
• The cords are the parenchyma of the red pulp; they are composed of reticular tissue w/ macrophages, red blood cells, and lymphocytes
Silver Stain
*Notice how reticular fibers are evident with silver stain and not H&E
*Notice the difference in appearance with the two different stains