The lymphatic system is an extensive network of vessels and nodes that collects lymph from the spaces between the cells and empties it into the venous circulation just before it enters the heart.
The lymph nodes protect the body against infection. important sites of lymphocyte formation. Lymphocytes are the white blood cells that manufacture antibodies, and during periods of active antibody formation the lymph nodes often become swollen and tender. only occur in mammals
Lymph vessels are found in all vertebrate. In most amphibians and reptiles and in some fishes, the lymph is propelled by pulsating lymph hearts. In other vertebrates, including all mammals, lymph movement depends primarily on external forces, such as the action of neighboring skeletal muscles, pulsations of nearby arteries, intestinal contractions, alterations of pressure within the chest during breathing, and the force of gravity.
things to remember
- remember: closed circulatory system in mammals
- diameter of blood and lymph capillaries is large enough to allow passage of blood cells
- lymph vessels are closed tubes (one way flow)
Water potential is the net effect of osmotic pressure and physical pressure on water movement