The Microstructure of Spleen and Head Kidney in Plectorhynchus cinctus

The spleen and head kidney are the major hemopoietic organs in fish. Through observation of the spleens microstructure in Plectorhynchus cinctus, it is found that the splenic capsule is very thin and the trabeculae are poorly developed. The splenic parenchyma is made up of white pulp and red pulp. The lymphocytes of white pulp aggregate into groups. The trabeculae liens and the lymphatic sheath could seldom be seen in spleen. The red pulp is made of splenic cord and splenic sinus. In the spleen, the ellipsoids are opened to the white and red pulps. In the head kidney, there are two type of veins (i.e. head-renal veins and portal veins) and a number of sinusoids with extensive lumina. The lymphocytes of head kidney distribute around portal veins and sinusoids, forming lymphocyte aggregate region. Granulocytes distribute around head-renal veins and sinusoids, and form a granulocyte aggregate region.