The Lymphatic System

Essential Questions The Lymphatic System What does the lymphatic system do? How do the parts of the lymphatic system work together?

Functions of the Lymphatic System The lymphatic system is part of the immune system and helps destroy microorganisms that enter the body. There are four main functions of the lymphatic system. It absorbs some of the tissue fluid that collects around cells. It absorbs fats from the digestive system and transports them to the circulatory system.

Functions of the Lymphatic System (cont.) It filters dead cells, viruses, bacteria, and other unneeded particles from tissue fluid and then returns the tissue fluid to the circulatory system. It helps fight off illness and infections and includes structures in which white blood cells develop.

Parts of the Lymphatic System The lymphatic system includes lymph vessels and the fluid they carry. Water, white blood cells, and dissolved materials such as salts and glucose make up tissue fluid, which leaks out of capillary walls and into the spaces that surround tissue cells. Cells absorb materials they need from tissue fluid and release wastes into it.

Parts of the Lymphatic System (cont.) About 10 percent of the tissue fluid is absorbed by the lymph vessels and is called lymph. lymph from Latin lympha, means “water”

Lymph vessels transport lymph by contraction of the muscles you use to move your body. C Squared Studios/Getty Images

Parts of the Lymphatic System (cont.) Lymph vessels include clusters of small, spongy structures called lymph nodes that filter particles, such as bacteria, viruses, and fungi, from lymph. Lymph nodes store white blood cells that attack and destroy the trapped particles. Large groups of lymph nodes, found in the neck, groin, and armpits, swell when your body increases its production of white blood cells to fight infection.

Parts of the Lymphatic System (cont.) Lymphocytes are white blood cells that destroy infection-causing microorganisms such as viruses and bacteria. Lymphocytes include B cells, which mature in the bone marrow, and T cells, which mature in the thymus.

Immature T cells move from bone marrow the to the thymus.

Parts of the Lymphatic System (cont.) Mature B cells and T cells move into the lymph and blood to help fight infection. The spleen is an organ of the lymphatic system that recycles worn-out red blood cells and produces and stores lymphocytes. Tonsils are lymph tissues in your throat that help protect your body from infection by trapping and destroying pathogens that enter your nose and mouth.

spleen

tonsils