Key Points
Spleen is an organ on the left side of the abdomen below the stomach.
It performs two major functions:
- Storage of blood - Blood vessels of spleen can alter their thicker and become wider or narrower depending on the situation. In case of emergency situations like trauma & severe injuries where a lot of blood gets lost, the spleen expand its vessels and hold the blood. This reserve blood is then transported to the organ where blood is required. For this reason the spleen is also called the blood bank of human body.
- Filtration of blood - Spleen filters the blood & removes the old & dead RBCs. It acts like a maze from which healthy RBCs can easily pass while the old & dead RBCs get stuck in it. These are then broken down in the spleen by macrophages. For this reason the spleen is also called as The Graveyard of RBCs.

Additional Information
Heart:
- The heart is a mesodermally derived organ, that is present in the thoracic cavity, in between the two lungs, slightly tilted to the left. It has the size of a clenched fist. It is protected by a double-walled membranous bag, pericardium, enclosing the pericardial fluid.
Liver:
- The liver is the largest gland of the human body. It performs the function of detoxification of harmful substances in the body
- For example, it converts harmful ammonia into urea, It also breaks down alcohol and other such substances in the blood.
Bone marrow :
- Bone marrow refers to the tissue located in the hollow interior of long bones. It is composed of adipose tissue, areolar tissue, and blood cells.
- Bone marrow is mainly of two types – red and yellow
