Lymph and You : the elusive immune system

Closely associates with circulation (sometimes called "the other circulatory system")
Helps to transport extra interstitial fluid, lymph, away from tissues, and helps to defend against disease
Lymph is collected by lymphatic capillaries and vessels. Lymphatic vessels can, and often do, give rise to lymph nodes. Several vessels can come together and empty into a lymphatic trunk, which then joins one of two collecting ducts – the thoracic duct (the larger) which receives lymph from the left side and the lower part of the body; and the right lymphatic gets lymph from the right side of the head and neck, arm and thorax. Both empty lymph into the subclavian vein, where it becomes part of venous return.
The skin has many lymphatic capillaries. Things are more likely to affect the lymphatic system than other systems.
How does lymph form? It originates from blood plasma, but lacks some of the larger proteins.
Lymph’s functions : return protein molecules to the bloodstream, and transporting foreign particles, including virues or bacteria, to the lymph nodes
Movement of lymph : is controlled by osmotic pressure of the tissue fluid and muscular activity around the lymphatic vessels, much like venous blood. Valves within the lymphatic vessels prevent backflow.

Interfering with lymph flow can lead to a backup and swelling due to fluid accumulation called an edema or lymphedema . A type of edema caused by filarial worms clogging lymphatic vessels is called elephantiasis.

Nodules within each node contain dense masses of lymphocytes and macrophages
Sinuses form the chambers for lymph to flow through
Lymph nodes occur in groups or chains along the larger lymphatic vessel pathways

Nodes you should know : cervical, axillary, pelvic cavity, inguineal, thoracic cavity, pelvic cavity, abdominal cavity and supratochlear

Lymph nodes are centers for lymphocyte production (in addition to the red bone marrow). Cells in the lymph nodes are responsible for the breakdown of foreign particles

The thymus, composed of lymphocyte-dense lobules, makes the special T-cells which provide immunity.
The spleen is the largest lymphatic organ, and it resembles a large lymph node

The spleen includes two types of tissue called pulp. White pulp is distributed throughout, but congregated into islands. Red pulp fills the spaces between white pulp islands.
White pulp is similar in structure to lymph node nodules. The white pulp nodules contain a lot of lymphocytes
Red pulp contains many RBCs and is analogous to the sinuses of lymph nodes. Red pulps also contains lymphocytes and macrophages
Red pulp contains extremely permeable capillaries. RBCs can leave the capillary to enter the venous sinuses of the red pulp. Old RBCs will probably rupture trying to do this, due to frailties of their membranes.