
Spleen: white pulp
The marginal zone is a region located at the interface of the PALS with the red pulp. The marginal zone contains numerous thin walled blood sinuses, which are supplied by radial branches from the central arteriole. The surrounding reticular tissue contains numerous lymphocytes and macrophages. The marginal zone is an important transit area for both immune cells and antigens and for the initiation of an immune response. 400x

Germinal center
The marginal zone is a region located at the interface of the PALS with the red pulp. The marginal zone contains numerous thin walled blood sinuses, which are supplied by radial branches from the central arteriole. The surrounding reticular tissue contains numerous lymphocytes and macrophages. The marginal zone is an important transit area for both immune cells and antigens and for the initiation of an immune response. 400x

Periarterial lymphoid sheath (PALS)
The marginal zone is a region located at the interface of the PALS with the red pulp. The marginal zone contains numerous thin walled blood sinuses, which are supplied by radial branches from the central arteriole. The surrounding reticular tissue contains numerous lymphocytes and macrophages. The marginal zone is an important transit area for both immune cells and antigens and for the initiation of an immune response. 400x

Red Pulp
The marginal zone is a region located at the interface of the PALS with the red pulp. The marginal zone contains numerous thin walled blood sinuses, which are supplied by radial branches from the central arteriole. The surrounding reticular tissue contains numerous lymphocytes and macrophages. The marginal zone is an important transit area for both immune cells and antigens and for the initiation of an immune response. 400x

Marginal zone
The marginal zone is a region located at the interface of the PALS with the red pulp. The marginal zone contains numerous thin walled blood sinuses, which are supplied by radial branches from the central arteriole. The surrounding reticular tissue contains numerous lymphocytes and macrophages. The marginal zone is an important transit area for both immune cells and antigens and for the initiation of an immune response. 400x

Marginal sinuses
The marginal zone is a region located at the interface of the PALS with the red pulp. The marginal zone contains numerous thin walled blood sinuses, which are supplied by radial branches from the central arteriole. The surrounding reticular tissue contains numerous lymphocytes and macrophages. The marginal zone is an important transit area for both immune cells and antigens and for the initiation of an immune response. 400x

Penicillar arteriole >
The central arteriole passes out of the PALS and into the red pulp as the penicillar arteriole which branches into capillaries that either supply the splenic cords or are continuous with the splenic sinuses.