What are the differences in structure between a lymphocyte and a phagocyte?

Lymphocytes and phagocytes are different types of white blood cells which serve to fight off infection of the body. They are part of the immune system which can recognize and subsequently attack and kill invading pathogens, along with remembering the pathogen in order to protect the body from a future attack. The body has non--specific defenses including skin, mucus, saliva, tears, or fever generation to try to stop an invasion of foreign cells. If this...

Lymphocytes and phagocytes are different types of white blood cells which serve to fight off infection of the body. They are part of the immune system which can recognize and subsequently attack and kill invading pathogens, along with remembering the pathogen in order to protect the body from a future attack. The body has non--specific defenses including skin, mucus, saliva, tears, or fever generation to try to stop an invasion of foreign cells. If this doesn't work, specific defenses are put into action, of which lymphocytes and phagocytes are a large part of.

The lymphocytes, or B cells, are able to produce special proteins known as antibodies. These are defenses against specific invaders that cause an infection. They travel to the infection through the blood and then either attack the invading germs or help to signal other cells to attack them. These Y-shaped proteins can bind to the antigens (foreign proteins) on the surface of invading cells. Later, T cells, another type of lymphocyte, can attack the foreign cells. Other lymphocytes can cause invading cells' membranes to rupture. 

B and T cells can even make memory cells which can remain for long periods of time so that if a new attack by the same pathogen occurs in the future, the body will be armed and ready to fight it off.

Phagocytes are capable of recognizing and engulfing dead cell parts and foreign invaders which includes disease pathogens by recognizing surface receptors as foreign rather than "self." The fact that antibodies have attached to the foreign antigens also helps the phagocytes to do their job. They subsequently surround and engulf the invaders which end up being destroyed by chemicals within the phagocyte. They essentially "eat" the foreign cells. Anything that is not recognized as "self" can be attacked which also includes allergens, cancer cells and even a transplanted organ or tissue.

The structure of a phagocyte is related to its function. It has receptors that help it to bind to the invader. It has lysosomes which are organelles that contain enzymes that help it to digest the invading pathogen. It is capable of surrounding and engulfing foreign cells by stretching around and engulfing the germ much like the way an amoeba feeds on prey. An intesting fact about a phagocyte's structure is that its nucleus is very irregular in shape.

Lymphocytes, which include B cells, T cells and killer T cells are basically small cells with a very large nucleus and little cytoplasm. They are very significant as they are the vital cells of the immune system and do most of the work of fighting off infections. The structure of lymphocytes and phagocytes can easily be distinguished when looking at a slide of blood. The link below has an excellent diagram comparing the structure of both cells.