How is the spleen like a lymph node How is it unlike a lymph

How is the spleen like a lymph node? How is it unlike a lymph node? Differentiate between humoral and cell-mediated immunity. (A paragraph or 2, for each)

Solution

Spleen and a lymph node are alike as both the organs act as haemopoietic organs. Haemopoietic organs are those organs in which formation of blood cellular components occurs.

They are unlike in the fact that spleen is that haemopoietic organ which filters blood with sinusoids while as lymph node filters lymph with sinusoids. Moreover Spleen is a prenatal (before birth) haemopoietic organ whereas lymph node is a postnatal (after birth) haemopoietic organ.

DIFFERENCE BETWEEN HUMORAL AND CELL MEDIATED IMMUNITY

When a foreign substance called antigen enters into human body, it is encountered through two ways, humoral and cell mediated immunity.

In humoral immunity B cells or antibodies recognise antigens and kill them. They also produce memory cells specific to each antigen which kill antigens if detected in future.

In contrast, cell mediated immunity uses T cells which circulate in the blood stream. In this system of immunity, antigens are tagged by cell surface proteins called as Major Histocompatibility Complexes (MHC). T-cells bind with MHC tagged antigens and kill them.