The spleen contains reticular and lymphatic tissue and is the largest lymph organ.
The spleen lies in the left hypochondriac region of the abdominal cavity between the fundus of the stomach and the diaphragm. It is purplish in colour and varies in size in different individuals.
The spleen is slightly oval in shape with the hilum in the lower medical border. The anterior surface is covered with peritoneum. It is enclosed in a fibroelastic calpsule that dips into the organ,forming trabeculae. The cellular material,consisting of lymphocytes and microphones,is called splenic pulp,and lies between the trabeculae. Red pulp is the part suffused with blood and white pulp consists of areas of lymphatic tissue where there are sleeves of lymphocytes and macrophages around blood vessels.
The structures entering and leaving the spleen at the hilum are:
- Splenic artery,a branch of the coeliac artery.
- Splenic vein,a branch of the portal vein.
- Lymph vessels.
- Nerves.
Blood passing through the spleen flows in sinusoids,which have distinct pores between the endothelial cells,allowing it to come into close association with splenic pulp.
