Human Anatomy and Physiology Lesson 13 pg. 220-222: Immune and Lymph System

The Spleen

The spleen is located in the upper left abdomen, It is the size of a fist. The heart and the spleen are about the same size. The spleen looks like an oversized lymph node. It is also the largest lymph organ, the spleen’s job is to filter impurities like a lymph node. Unlike the lymph node however, the spleen filters blood instead of lymph. Red blood cells are consumed by phagocytes when their short life span is over. The spleen removes the damaged and old red blood cells. The spleen is storage area for the blood also. It is possible to live without the spleen, like in cases when the spleen has diseases or is infected, those people go into surgery to have it removed. When the spleen is gone, the liver removes the dead blood cells instead. Without the spleen though, the body is prone to infection and must regularly take antibiotics.

Thymus

The thymus is located in the chest next to the heart. This organ is a boot camp for lymphocytes. There are many lymphocytes in the thymus for special training. These lymphocytes in the thymus are called T-cells or T lymphocytes. For both names, the T stands for thymus.

Immunity

The skin is basically like a stone wall for your body. Mucus and cilia in the nose trap invaders, tears are antibacterial moisturizer, and oil glands on the skin destroy bacteria laying on your skin. There are helpful bacteria in the intestines but if found outside the intestines, they are treated and are pathogens/bacteria. These defenses are called innate defenses and they are basically moats and walls for your body. Macrophages, like lymphocytes and phagocytes, eat bacteria. Inflammation is good though annoying. When there is a large amount of bacteria in a place, pus will form. Pus is made of damaged tissue, dead (and living) bacteria, and dead white blood cells. The pus is carried away by macrophages. If there is a lot of infected tissue, you will have a fever. Fevers are supposed to destroy bacteria and viruses. The white blood cells and inflammatory proteins tell the brain to increase the body’s temperature.