LYMPHATIC SYSTEM Dr Rozzana Mohd Said

ORGANIZATION Consists of: Lymph Lymphatic vessels Lymphoid tissues and organs Lymphocytes + phagocytes + other cells

FUNCTIONS Primary function: To produce, maintain and distribute lymphocytes for body defense mechanisms Secondary function: To return fluid into the general circulation so that normal blood volume is maintained To distribute hormones, nutrients and waste products from tissues of origin to the general circulation

The system The lymphatic system is filled with millions of one-way valves, which allows the lymph fluid to flow in only one direction - usually upward away from gravity. The lymphatic system collects toxins in the body If this flow is impaired, the fluid becomes thick and toxic.

LYMPHATIC VESSELS small amount of interstitial fluid that remains is picked up by tiny vessels called lymph capillaries. lymph capillaries wall very porous

LYMPHATIC VESSELS lymph capillaries drain into still larger vessels that make up the lymphatic system. flow through the lymph vessels is quite slow Lymphatic vessels carry lymph, a colorless liquid, throughout the body. Along lymph vessels are small bean-shaped glandular nodules called lymph nodes.

LYMPHATIC VESSELS Afferent lymphatic vessels carry lymph into the nodes where waste products and some of the fluid are filtered out Efferent lymphatic vessels carry lymph out of the node to continue its return to the circulatory system.

BLOCKAGE OF THE LYMPH VESSELS Elephantiasis. Elephantiasis is a condition of extreme edema that occurs when lymph vessels become blocked by filarial worms. Here the left leg is swollen with the fluids accumulated in the tissues as a result of the blockage.

LYMPHATIC CIRCULATION All the lymph collected from the entire left side of the body, the digestive tract and the right side of the lower part of the body flows into a single major vessel, the thoracic duct.

Drainage area

The Left Drainage Area removes lymph from the: Left side of the head and neck Left arm and the left upper quadrant Lower trunk Both legs

The Right Drainage Area removes lymph from the: Right side of the head and neck Right arm Upper right quadrant of the body. Lymph from this area flows into the right lymphatic duct. This duct returns the lymph to the circulatory system by draining into the right subclavian vein.

LYMPH Lymph originates as blood plasma lost from the circulatory system, which leaks out into the surrounding tissues within the lymphatic system the fluid is called lymph, and has almost the same composition as the original interstitial fluid.

LYMPH The production of lymph is increased by increased blood pressure in the capillaries and/or a decreased concentration of plasma proteins (such as occurs in prolonged malnutrition). The lymphatic system may be unable to handle the increased volume of lymph, and it may accumulate in the tissues and distend them. This condition is known as edema.

POSITION OF LYMPHATIC ORGANS IN THE BODY

LYMPHATIC ORGANS Tonsil: clusters of lymphatic tissues just under the mucous membranes that line the nose, mouth, and pharynx. Nasopharyngeal tonsils / adenoids: at the back of the nose, at the meet of the back of throat

LYMPHATIC ORGANS Peyer patch: lymphoid tissue on the visceral surface of the small intestine.

LYMPHOID ORGANS Spleen: it is similar to a lymph node in shape and structure but it is much larger

LYMPHOID ORGANS Thymus: a soft organ with two lobes that is located anterior to the ascending aorta and posterior to the sternum.

LYMPH NODES Lymph nodes are scattered throughout the lymphatic system groin armpits abdomen and neck. Lymph nodes also manufacture antibodies and lymphocytes These contain cavities - called sinuses - into which the lymph flows The walls of the sinuses are lined with phagocytic cells filtering mechanism heavy infection - "swollen glands".

STRUCTURE OF THE LYMPH NODES

LYMPHOCYTES A lymphocyte is a type of white blood cell present in the blood lymphocytes help provide a specific response to attack the invading organisms Lymphocytes help to protect the body against tumors (tissues that grow more rapidly than normal) lymphocytes can also cause the rejection of tissues during organ transplants because they interpret these tissues as foreign invaders

LYMPHOCYTES Lymphocytes are formed in lymphatic tissue throughout the body lymphatic tissue include the spleen, thymus, tonsils, and lymph nodes Lymphocytes are also made by fetal stem cells and develop in the bone marrow After the lymphocytes are formed, they are released into the circulating blood.

LYMPHOCYTES two types of lymphocytes T cells and B cells differ in function and the molecules that are on their surface 15% to 40% of white blood cells are lymphocytes

In general, the lymphatic system: Drains fluid back into the general circulation Filters lymph Fight infections