Biology - The Lymphatic System

Lymphatic System

• a one way system

• a secondary transport system

Functions of Lymphatic System

• returns tissue fluid to the blood

• defends the body against infection

• transports fat

Lymph Nodes

• swellings in the lymph vessels

• filter bacteria

• store lymphocytes (white blood cells), some of these kill microorganisms and others produce antibodies

Tissue Fluid

• is plasma without red blood cells, platelets or large proteins

• surrounds all body cells and helps transport materials in and out of cells

Tissue Fluid Returns to the Plasma

• most enters blood capillaries

• some enters dead-ending lymph vessels, where it is called lymph

Lymph

• is made from tissue fluid

• contains white blood cells, proteins and fats

Lymph Moves in Lymph Vessels

• muscles in the vessel walls

• general body movement

Valves

control the direction of lymph flow

Subclavian Vein

lymph returns to the blood through this vein, located near the collar bones