structure of Spleen (2)

This a low power image of the Spleen. First of all notice how the over all organization of the spleen looks like a BIG MESS. It sounds funny but, that is one way to remember the spleen. There is stuff all mixed up together. The "stuff" is first the Capsule, indicated by the black arrows that covers the whole organ. There are two main organizations of the rest of the spleen, White Pulp and Red Pulp. The red arrows are pointing to the Red pulp and the blue arrows are pointing to the White Pulp. Again notice how these two pulps just mix with each other all over the place. Where there is a red tint to it, it is Red pulp. Where it is darker, it is white pulp.
Black arrow - Capsule
Red arrow - Red Pulp
Blue arrow - White Pulp
This is another image of the spleen in low power. Here you can see the Capsule (blue arrows) that encapsulated the whole organ. Notice how it looks like a big "mess". It may sound funny but that is the best way to identify the spleen that it looks like a big mess. Also notice the Trabeculae, (red arrows) which are extensions of the capsule into the spleen.
Blue arrow - Capsule
Red arrow - Trabeculae
Here is a another look at the Red and White Pulps. The White Pulp, (blue arrows) is composed of mainly Lymphocytes (White Blood Cells), hence the name white pulp. You may or may not find Primary or Secondary Lymph Nodules with in the White pulp. The Red Pulp (red arrows) is the blood filtering component of the spleen. It is made up of Splenic Cords and Splenic Sinuses made up of a meshwork Reticular fibers involved in the filtering process.
Red arrows - Red Pulp
Blue arrow - White Pulp
Here is a close up of the White Pulp. The Yellow arrow is pointing to the Central Artery. These are the arteries running through the white pulp around which the lymphocytes congregate around. This congregation is known as the Periarteriole Lymphatic Sheath (PALS). The PALS around the artery are dominated by T-cells, while the Nodules in the White pulp (blue arrow) are dominated by B-Cells. In this image the B-cells in the nodule have already come in contact with antigen and are actively dividing, proven so by the presence of the Germinal Center, and the Corona (red arrow).The yellow dotted line is drawing the border between the White pulp and the Red Pulp. Can you see the difference in the texture of the Red pulp from the white pulp?
Yellow arrow - Central Artery
Blue arrow - Germinal Center of Nodule
Red arrow - Corona of Nodule
Yellow dotted line - Border between White and Red Pulp
This is a close up of the Red Pulp. As mentioned above, the Red pulp is composed of Splenic Sinuses (red arrows) and Splenic Cords (green arrows). The Cords are made up of a meshwork of Reticular Fibers and Erythrocytes, Macrophages, Lymphocytes, Plasma Cells, and Granulocytes. It is here where the Macrophages are getting rid of old Red Blood Cells. The sinuses are the spaces in between the Cords where the blood filters through.
Red arrow - Splenic Sinuses
Green arrow - Splenic Cords

Spleen

Spleen (trabeculae)

Spleen (red and white pulp)

Spleen (White Pulp)

Splenic Cords and Sinuses