Lymphatic and Immune System

Lymph

• a clear, watery fluid
• surrounds the body's cells
• flows in lymphatic system: thin walled vessels
• close relationship with blood, but does differ from blood

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• Rich in two types of white blood cells
• Lymphocytes
• Monocytes

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• The liquid part of lymph contains:
• water
• salts
• sugar
• metabolic waste (urea, creatinine)

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• originates from the blood
• ends back in the bloodstrem

same fluid that filters blood capillaries

• interstitial fluid passes continuously into specialized, thin walled vessels called lymph capillaries: course through tissue spaces
• When in lymph cappillaries it is called lymph instead of interstitial fluid.

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• passes through larger lymph vessels and clusters of lymph tissues (lymph nodes)
• Finally reaches large lymph vessels in the upper chest
• large lymph vessels empty into the bloodstream

Functions of the Lymphatic System

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• drainage system transports proteins & fluids from blood capillaries back into the bloodstream
• Absorbs lipids from the small intestine and puts into bloodstream
• defend our body against foreign organisms: viruses and bacteria
• Lymphocytes & monocytes protect the body by producing antibodies and attacks foreign cells and organisms.

Lymphatic System

Lymphatic Capillaries

• Begin in the spaces around cells throughout the body
• Thin-walled tubes that carry lymph from the tissue spaces to larger lymph vessels

Lymph Vessels

• thicker walled and containing valves to help keep lymph flowing in the right direction

Lymph Nodes

• masses of lymph cells and vessels, surrounded by CT
• Located along the path of the lymph vessels

Lymphocytes

• Lymph nodes produce lymphocytes. They also filter lymph and trap substances from infections, and inflammatory and cancerous lesions

Macrophages

• are located in lymph nodes as well as the spleen, liver, lungs
• Swallow (phagocytose) foreign substances
• when bacteria are present in lymph nodes that drain a particular area of the body, the nodes become swollen

B lymphocytes (B cells)

• present in the nodes
• produce antibodies

T lymphocytes (T cells)

• attack bacteria and foreign cells
• recognize a cell surface protein as foreign, attaching to the foreign or cancerous cells
• poke 'hoses" in them, injecting them with toxic chemicals

major sites of lymph node concentration

• cervical
• axillary (armpit)
• mediastinal
• inguinal (groin)
• Tonsils-masses of lymph tissue in the throat near the back of the mouth
• adenoids- enlarged lymph tissue in the part of the throat near the nasopharynx

Lymph Flow

• all lymph vessels lead toward the thoracic cavity
• Empty into two large ducts in the upper chest
• 1. the right lymphatic duct-drains the right sife of the head and the chest
• 2. thoracic duct- drains the lower body and the left side of the head
• 3. both ducts carry the lymph into blood

Spleen

• located in LUQ
• Functions:
• Destruction of old erythrocytes by macrophages
• Filtration ofmicroorganisms
• activation of lymphocytes by antigens filtered from the blood
• Storage of blood, especially erythrocytes and platelets

spleen cont.

• Susceptible to injury-a sharp blow to the upper abdomen can cause to rupture
• A ruptured spleen can lead to massive hemmorrhage
• immediate surgical removal may be necessary
• After the spleenectomy, the liver, bone marrow, and lymph nodes take over the functions of the spleen

The Thymus Gland

• Located in upper mediastinum, between lungs
• composed of nests of lymphoid cells
• Importan for childhood immune syste development

Immune System

• specialized to defend the body against antigens
• Leukocytes (neutrophils, monocytes, macrophages) are located in tissues
• Lymphoid organs (lymph nodes, spleen, and thymus) produce lymphocytes and antibodies

Immunity

• The body's ability to resist foreign organisms and poisons that damage tissues and organs
• Natural Immunity
• 1. Protection inherited and present at birth
• 2. not dependent on previous contact with infectious agents

Acquired immunity

• body's ability to form antibodies
• vaccinations
• immediate immunity-antitoxins
• infections of antibodies, immunoglobulins
• babies receive maternal antibodies: placenta or breast milk

Immunotherapy

• The use of antibodies, B cells, and T cells to Tx diseases such as cancer

Pathology Immunodeficiency

• Severe Combined Immunodeficiency Disease (SCID)
• Acquired Immunodeficiency Syndrome
• Kaposi Sarcoma

Pathology-Hypersensitivity

• Allergy- an abnormal hypersensitivity acquired by exposure to an antigen
• 1. allergic rhinitis
• 2. systemic anaphylaxis
• 3.asthma
• 4. hives
• 5. atopical dermatitis
• 6. atopy-

Pathology Malignancies

• Lymphoma
• Hodgkin disease
• Non-Hodgkin lymphoma
• Multiple Myeloma
• Waldenstrom macroglobulinemia
• Thymoma

Laboratory Tests

• CD4+ cell count
• ELISA
• Western blot test
• Immunoelectrophoresis
• Viral Load test

Clinical Procedures

• CT- computerized Tomography scan