LYMPHATIC SYSTEM

Lymphatic comes from the Latin word Lymphaticus “connected to water”. The lymph system is a network of organs, lymph nodes, lymph ducts and lymph vessels that make and move lymph from tissues to the bloodstream. The lymph system is a major part of the body’s immune system. The lymphatic system collects excess and proteins  from body tissues and carries them back to the bloodstream. There are 600 to 700 lymph nodes in the human body that filter the lymph before it returns to the circulatory system.

Lymph is a clear to white fluid made of:

• White blood cell, especially lymphocytes (cell that defend you against germs).
• Fluid from the intestines called chyle, which contains proteins and fats.

Organization

The lymphatic system can be broadly divided into the conducting system and the lymphoid tissue. The conducting system carries the lymph and consists of tubular vessels that include the lymph capillaries, the lymph vessels, and the right and left thoracic ducts.

The lymphoid tissue is primarily involved in immune responses and consists of lymphocytes and other white blood cells enmeshed in connective tissue through which the lymph passes. Regions of the lymphoid tissue that are densely packed with lymphocytes are known as lymphoid follicles. Lymphoid tissue can either be structurally well organized as lymph nodes or many consist of loosely organized lymphoid follicles known as the mucosa associated lymphoid tissue (MALT).

COMPOMEMTS IN THE LYMPHATIC SYSTEM

Lymph Nodes

Are soft, small, round or bean shaped structures. They usually cannot be seen or easily felt. They are located in clusters in various parts of the body, such as the neck, armpit, groin, and inside the center of the chest and abdomen. Lymph nodes make immune cells that help the body fight infection. They also filter the lymph fluid and remove foreign material such as bacteria and cancer cells.

Lymph Capillaries

Begin blindly in the tissue spaces and from intricate network. Lymph capillaries are absent from the cellular structures like brain, spinal cord, splenic pulp and bone marrow. The lymph capillaries joint to from lymphatic, which are superficial and deep lymphatic. The superficial lymphatic accompany  veins, while the deep lymphatic accompany arteries.

Central Lymphoid Tissues

Comprise bone marrow and thymus. All pluripotent lymphoid stem cells are initially produced by liver and spleen. The stem cells undergo differentiation in the central lymphoid tissue, so that the lymphocytes become competent defensive elements of the immune system.

Bone marrow helps differentiation of the (committed) B-lymphocytes which are capable of synthesizing antibodies after getting transformed into plasma cells.

T-cells being uncommitted can react to a wide range of foreign antigenic stimuli. These respond by cytotoxic cell killing (killing virus-infected cells, neoplastic cells, fungi, tissue grafts, etc), by ‘arming’ macrophages and by triggering the large mononuclear cells (killer cells) and the ‘helper’ activity of B-lymphocyte.

Circulating Pool Of Lymphocytes

The pool contains mature progenies of B- and T-Lymhocytes which may be called upon during antigenic emergencies.

FUNCTIONS

The lymphatic system has multiple interrelated function:

It is responsible for the removal of interstitial fluid from tissues.

It absorbs and transports fatty acids and fats as chyle from the digestive system.

It transports white blood cells to and from the lymph nodes into the bones.

The lymph transports antigen presenting (APCs) such as dendritic cells to the lymph nodes where an immune response is stimulated.

DISEASE OF THE LYMPHATIC SYSTEM

LYMPHEDEMA

Is the swelling caused by the accumulation of lymph fluid which many occur if the lymphatic systems is damaged or has malformations. It usually affects limbs, though face, neck and abdomen many also be affected.

Causes of lymphedema include:

• Infection
• Scar tissue radiation therapy or surgical removal of lymph nodes.
• Inherited conditions in which lymph nodes or vessels are absent or abnormal.
• Cancer

Lymphoma

• Is a cancer of the lymphatic system. Types of lymphoma:
• Hodgkin
• Non-Hodgkin lymphoma

Hodgkin Disease

1. The first sign of Hodgkin disease is often an enlarged lymph node.
2. The disease can spread to nearby lymph nodes.
3. Later it many spread to the lungs, liver or bone marrow.
4. The cause is unknown
5. Hodgkin disease is are symptoms include:

• Painless swelling of the lymph nodes in the neck, armpits or groin
• Fever and chills
• Night sweats
• Weight loss
• Loss of appetite
• Itchy skin

Non-Hodgkin

Begin when a type of white blood cell, called a T-cell or B-Cell becomes abnormal

The cell divides again and again making more and more abnormal cells

1. These abnormal cells can spread to almost any other part of the body
2. Most of the time, doctors can’t determine why a person get non-Hodgkin lymphoma
3. Non-Hodgkin lymphoma can cause many symptoms such as:

• Swollen, painless lymph nodes in the neck, armpits or groin
• Unexplained weight loss
• Fever
• Soaking night sweats
• Coughing, trouble breathing or chest pain
• Weakness and tiredness that don’t go away
• Gain, swelling or a feeling of fullness in the abdomen.

CASTLEMAN DISEASE

Is caused by benign tumors that affect the lymph nodes. While not specifically a cancer, it is similar to a lymphoma and is often treated with chemotherapy. Localized Castleman disease affects the lymph nodes of the stomach and chest. Multicentric Castleman disease affects greater than one region of lymph nodes as well as lymphoid containing organs such as the spleen.

ELEPHANTIASIS

Infection of the lymphatic vessels causes a thickening of the skin and enlargement of underlying tissue, especially in the legs and genitals. There is an abnormal accumulation of watery fluid in the tissues (edema) causing severe swelling. The skin usually develops a thickened, pebbly appearance and may become ulcerated and darkened. Fever, chills and a general feeling of ill health (malaise) many be present.

Elephantiasis many also affect the male and female genital organs. In a male there may be enlargement of the scrotum and the penis may be retracted under skin which has become thickened, non-elastic, hot an painful. The spermatic cords many become thickened.

The external parts of the female genital organs (vulva) may also affected by elephantiasis. A long timorous mass covered by thickened and ulcerated skin many develop between the thighs. There may also be an enlargement of the lymph nodes of the legs.

Affected Population

Elephantiasis is most commonly found in African nations.