1. THE LYMPHATIC SYSTEM AND IMMUNITY
Chapter 15
THE LYMPHATIC SYSTEM AND IMMUNITY

2. FUNCTIONS OF THE LYMPHATIC SYSTEM
Lymph fluid acts as intermediary between blood, capillaries, and tissues
Lymph vessels transport tissue fluid back into circulatory system
Lymph nodes produce lymphocytes and filter harmful bacteria
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3. FUNCTIONS OF THE LYMPHATIC SYSTEM
Spleen produces lymphocytes and monocytes, acts as a reservoir for blood, and recycles red blood cells
Thymus gland produces T-lymphocytes for immune system
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LYMPH
Lymph diffuses from capillaries into tissue spaces
Lymph acts as an intermediary between blood in capillaries and tissues
Lymph carries digested food, oxygen, and hormones to cells
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LYMPH VESSELS
Lymph vessels accompany and are similar to veins
They are in almost all tissues and organs that have blood vessels
Lymph only travels in direction from body organs to the heart
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LYMPH VESSELS
2 large main lymphatics
Thoracic duct (left lymphatic duct)
Receives lymph from left side of head, neck, abdominal area, and lower limbs
Right lymphatic duct
Circulates lymph from right arm, right side of head, and upper trunk to the superior vena cava
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LYMPH NODES
Lymph nodes provide sites for lymphocyte production and screen harmful substances from the lymph
Bacteria and other harmful substances in large quantities may injure the lymph node
Adenitis - swelling in lymph gland
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LYMPH NODES
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TONSILS
Tonsils are masses of lymphatic tissues capable of producing lymphocytes and filtering bacteria
Three pairs of tonsils
Palatine
Adenoids
Lingual
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SPLEEN
The spleen is a saclike mass of lymphatic tissue that forms lymphocytes and monocytes
The spleen filters blood that passes through it, destroying old or fragile red blood cells
The spleen stores large amounts of red blood cells
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THYMUS GLAND
The thymus’s function is to produce lymphocytes called T-lymphocytes
The thymus is also an endocrine gland because it secretes a hormone called thymosin that stimulates the production of lymphoid cells
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12. DISORDERS OF THE LYMPH SYSTEM
Lymphadenitis - enlargement of the lymph nodes that occurs when infection is present
Hodgkin’s disease - form of cancer of lymph nodes
Infectious mononucleosis - caused by Epstein-Barr virus
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IMMUNITY
Immunity is the body’s ability to resist invaders and disease
Acquired immunity - reaction to exposure of invaders
Passive acquired immunity - borrowed immunity from another person’s blood that produces immunity immediately
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IMMUNITY
Active acquired immunity
Natural acquired immunity results from having had and recovering from disease
Artificial acquired immunity is the result of inoculation with vaccine, antigen, or toxoid
Immunization is increasing the resistance to infection through artificial means
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IMMUNITY
Autoimmunity
Occurs when a person’s own immune system targets normal cells, tissues, and organs of person’s own body
Causes range from genetics to viruses to sunlight exposure
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IMMUNITY
Hypersensitivity
Body’s immune system fails to protect itself against foreign material
Antibodies irritate certain body cells
Allergen - antigen causes allergic responses
Anaphylactic shock - severe, often fatal allergic reaction
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AIDS/HIV
Acquired - disease is not inherited
Immune - body’s natural defenses
Deficiency - lacks cellular immunity
Syndrome - diagnosed from sets of diseases or conditions present
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AIDS/HIV
Human immunodeficiency virus (HIV) destroys T4-lymphocyte cells without causing symptoms
Opportunistic infections arise
Three outcomes of HIV infection:
AIDS
AIDS-related complex (ARC)
Asymptomatic infection
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AIDS/HIV
Transmission of AIDS
Sexual contact with infected partner
Sharing hypodermic needles among IV drug users
In utero or at birth of infected mother
Transfusion of blood
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AIDS/HIV
Screening tests for HIV/AIDS
There are two antibody tests
Enzyme-linked immunosorbent assay (ELISA) - detects antibodies for AIDS but not the virus
Western blot is the follow-up to confirm ELISA results
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AIDS/HIV
Symptoms of HIV/AIDS
Flu-like symptoms
Fever
Headache
Malaise
Enlarged lymph glands
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AIDS/HIV
There is no cure for AIDS yet certain drugs are used to slow the virus
Transmission is prevented by following the CDC’s Standard Precautions
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