Introduction by Period 7, 2014

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The four parts of the lympatic system include the vessels, fluid, Lyphocytes and the Lymphoid tissues and organs.

• The vessels: the lymphatic vessels begin in the peripheal tissues and end at the connectrions to the veins, they are also called lymphatics.

• Fluid: the fluid called lymph looks like plasma but it contains lower concentration of suspended proteins. this fluid flows through the lyphatic vessels.

• Lymphocytes: Lymphocytes are specialized cells that preform special functions to defend the body.

• Lyphoid tissues and organs: lyphoid tissues an example is the tonsils;are a group of loose connective tissue and lymphocytes in stuctures called lymphoid nodules. Lymphoid organs the examples include lymph nodes, sleen, and thymus; are more complex containing more lymphocytes and they are connected to lymphatic vessels.

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Production, maintenance, & distribution of lymphocytes

• Lymphocytes react to bacteria and viruses (invading pathogens), abnormal body cells, and foreign proteins. They attempt to eliminate them.Return of fluid and solutes from peripheral tissue to the blood

• Maintains normal blood volume and eliminates local variations in the composition of the interstitial fluid. A break in the Lymphatic vessel can cause a fatal decline in blood volume.

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Distribution of hormones, nutrients, & waste products from

their tissues of origin to the general circulation

• Helps substances that are unable to enter the blood stream directly can do so by way of the Lymphatic vessels.

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Lymphatic Vessels

• Lymphatic vessels carry lymph from peripheral tissues to the venous system.

• Lymphatic capillaries begin as blind pockets in peripheral tissue and are lined by simple squamous tissue.

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Lymphatic vessels

• The lymphatic vessels empty into two large collecting structures called lymphatic ducts.

• The thoracic duct collects lymph from the lower abdomen, pelvis, and lower limbs, and from the left half of the head, neck, and chest.

• It empties its collected lymph into the venous system near the junction between the left internal jugular vein and the left subclavian vein.

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Lymphatic vessels• The smaller right lymphatic duct delivers

lymph from the right side of the body above the diaphragm.

• It empties into the right subclavian vein.• Blockage of the lymphatic drainage is

known as a condition called lymphedema.

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Lymphocytes

A cell of the lymphoid system that participates in immune response. Lymphocytes account for roughly 25%of the

circulating white blood cell population. The three types include T-Cells, B-Cells, and NK Cells.

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T-Cells and B-Cells• T-cells or thymus-dependent cells are lymphocytes responsible

for cellular immunity and for the coordination and regulation of the immune response. Cytotoxic T Cells directly attack foreign cells or virus infected body cells.

• B-cells or bone-marrow cells are lymphocytes capable of differentiating into the plasma cells that produce antibodies. Antibodies bind to specific chemical targets called antigens, which are usually pathogens.

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NK Cells

• NK cells or natural killer cells are lymphocytes that attack foreign cells, normal cells infected with viruses, and cancer cells that appear in normal tissues.

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Lymph Nodules – Lymph nodules are masses of lymphoid

tissue that are not surrounded by a fibrous capsule.

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Structure and Location

• -Lymph Nodules are found beneath the epithelial lining various organs of the respiratory, digestive, and urinary systems.

• -There are different types of lymph nodules such as the tonsils, which guard the entrance of the digestive and respiratory tracts.

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Infections and Description

• -Nodules are open to the external environment, the provide a root of entrance to the body to potential dangerous toxins and organisms.

• -The lymphocytes in a lymphoid nodule are not always able to destroy bacterial or viral invaders, and if pathogens establish in a lymph nodule, a inflammatory response begins.

• -There are two main infections that happen from the nodules called tonsilitis and appendicitis.

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Lymphoid Organ : NodesLymph Nodes are small oval organs that filter and purify the lymph before it reaches the venous system.

They are located in regions where they detect harmful intruders before reaching vital organs.

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Lymphoid Organ : Thymus The Thymus is a pink gland posterior to the sternum that produces T- Cells and maturation.

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Lymphoid Organ : SpleenThe spleen filters blood and removes abnormal cells and initiates cells to antigens in blood.

The spleen also stores iron fromrecycled RBC’s.

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Autoimmune disorders develop when the immune response mistakenly targets normal body cells and tissues.

Autoantibodies-misguided antibodies that attack normal body cells and tissues

Examples of autoimmune disorder: • Rheumatoid arthritis• Insulin-dependent diabetes mellitus (IDDM)

Many autoimmune disorders appear to be cases of mistaken identity.

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Immunodeficiency Disease is when the immune system fails to develop normaly or the immune response is blocked in some way.

Severe combined immunodeficiency disease- fails to develop either cell or antibody-mediated immunity.

Example of Immunodeficiency is AIDSAIDS- a result of a viral infection that targets primarily helper T cells.

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AllergiesType I- immediate hypersensitivity- The reaction may involve skin, eyes, nasopharynx, bronchopulmonary tissues and gastrointestinal tract. The reaction may cause a range of symptoms from minor inconvenience to death. The reaction usually takes 15 - 30 minutes from the time of exposure to the antigen

Type II- cytotoxic reactions- The antigens are normally endogenous, although exogenous chemicals which can attach to cell membranes can also lead to type II hypersensitivity. Drug-induced hemolytic anemia, granulocytopenia and thrombocytopenia are such examples. The reaction time is minutes to hours.

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AllergiesType III- immune complex disorders- The reaction may be general or may involve individual organs including skin, kidneys, lungs, blood vessels, joints or other organs. This reaction may be the pathogenic mechanism of diseases caused by many microorganisms. The reaction may take 3 - 10 hours after exposure to the antigen

Type IV- delayed hypersensitivity- The classical example of this hypersensitivity is tuberculin reaction which peaks 48 hours after the injection of antigen. The lesion is characterized by induration and erythema.

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