Hint: The purification of the blood takes place in the spleen and blood cells are also stored in it.
Spleen is important for blood purification and urgent storage of blood cells; it acts as a reservoir of blood and is known as the Blood bank of the body.
Hence, option B: Spleen, is the correct answer.
- The spleen is located in the left part of the diaphragm underneath and has a smooth, convex surface that faces the diaphragm. It is beneath the ninth, tenth, and eleventh ribs.
- The gastric surface is directed forward, upward and towards the middle, it is broad and concave, and is in contact with the posterior wall of the stomach.
- Below this, it is in contact with the tail of the pancreas. It is flattened, considerably narrower than the gastric surface, and is in relation with the upper part of the anterior surface of the left kidney and occasionally with the left adrenal gland.
- The spleen plays important roles as it removes old red blood cells and holds a reserve of blood, which is crucial in case of hemorrhagic shock.
- As a part of the mononuclear phagocyte system, it metabolizes haemoglobin removed from senescent red blood cells (erythrocytes).
- The spleen is a hub of activity of the mononuclear phagocyte system and is analogous to a large lymph node, as its absence causes a predisposition to certain infections.
Note: In humans, the spleen is purple in colour and is in the left upper quadrant of the abdomen, which is similar in structure to a large lymph node.