Spleen
The spleen, in the upper left quadrant of the abdomen, filters blood, responding to blood-borne antigens, and also removes aged red blood cells and platelets. The spleen is subdivided into white pulp and red pulp, named because of their appearance in the fresh state. Reticular connective tissue forms the stroma. Because it filters blood, the spleen has an intricate vascular supply. 40x
Capsule >
Because the spleen projects into the abdominal cavity, it is covered by a serosa, which overlies a dense connective tissue capsule. Long trabeculae extend from the capsule into the organ. Arteries enter the spleen at its hilum and travel in the trabeculae to supply splenic parenchyma. Veins leave the parenchyma, enter the trabeculae and exit at the hilum. Reticular connective tissue forms the stroma of the splenic interior.
Trabecula
Because the spleen projects into the abdominal cavity, it is covered by a serosa, which overlies a dense connective tissue capsule. Long trabeculae extend from the capsule into the organ. Arteries enter the spleen at its hilum and travel in the trabeculae to supply splenic parenchyma. Veins leave the parenchyma, enter the trabeculae and exit at the hilum. Reticular connective tissue forms the stroma of the splenic interior.
White pulp >
The white pulp surrounds arterioles after they leave the trabeculae. White pulp consists of both diffuse (T-dependent) and nodular (B-dependent) lymphoid tissues. The diffuse tissue forms a sleeve around each arteriole, called the periarterial lymphoid sheath (PALS). The lymphoid nodules are suspended within these diffuse areas of red pulp.
- Periarterial lymphoid sheath (PALS)
The white pulp surrounds arterioles after they leave the trabeculae. White pulp consists of both diffuse (T-dependent) and nodular (B-dependent) lymphoid tissues. The diffuse tissue forms a sleeve around each arteriole, called the periarterial lymphoid sheath (PALS). The lymphoid nodules are suspended within these diffuse areas of red pulp.
- Lymphoid nodules
The white pulp surrounds arterioles after they leave the trabeculae. White pulp consists of both diffuse (T-dependent) and nodular (B-dependent) lymphoid tissues. The diffuse tissue forms a sleeve around each arteriole, called the periarterial lymphoid sheath (PALS). The lymphoid nodules are suspended within these diffuse areas of red pulp.
- Germinal centers
The white pulp surrounds arterioles after they leave the trabeculae. White pulp consists of both diffuse (T-dependent) and nodular (B-dependent) lymphoid tissues. The diffuse tissue forms a sleeve around each arteriole, called the periarterial lymphoid sheath (PALS). The lymphoid nodules are suspended within these diffuse areas of red pulp.
Red pulp >
The red pulp consists of splenic cords (of Billroth) and splenic sinuses. Splenic cords are composed of a variety of lymphatic cells supported by reticular connective tissue. The sinuses are vascular channels between the splenic cords. Because of the large number of these vascular sinuses, red pulp appears red in fresh tissue.
- Veins in red pulp
The red pulp consists of splenic cords (of Billroth) and splenic sinuses. Splenic cords are composed of a variety of lymphatic cells supported by reticular connective tissue. The sinuses are vascular channels between the splenic cords. Because of the large number of these vascular sinuses, red pulp appears red in fresh tissue.
