The Lymphatic System and Immunity Functions: Lymph- fluid that goes between capillary blood and tissues Lymph vessels- transport excess tissue fluid back into circulatory system Lymph nodes- produce lymphocytes, filter out harmful bacteria Spleen- produces lymphocytes and monocytes, blood reservoir, recycles old red cells Thymus gland- produces t-lymphocytes

Lymph Straw-colored fluid (similar to plasma) Interstitial fluid or tissue fluid because it is in the spaces between cells Composed of H2O, lymphocytes, some granulocytes, O2, digested nutrients, hormones, salts, CO2 and urea (urea- a waste product of metabolism from the protein that we eat)

No red blood cells or protein molecules (too large) Carries digested food, O2 and hormones to cells Carries wastes back to capillaries for excretion Since the lymphatic system has no pump, skeletal muscle action squeezes lymph along Valves prevent backward flow

Lymph Vessels Closely parallel veins Located in almost all tissues and organs that have blood vessels Tissue lymph enters small lymph vessels which drain into larger vessels called lymphatics- they flow into one of two large, main lymphatics- the thoracic duct or right lymphatic duct.

Lymph flows only in one direction- from body organs to the heart 1. Thoracic duct gets lymph from left side of chest, head and neck, abdominal area and lower limbs 2. Lymph then flows into the left subclavian vein 3. Then the superior vena cava 4.. Finally the heart Lymph flows only in one direction- from body organs to the heart

Lymph Nodes Tiny, oval shaped- size of pinhead to size of almond Located alone or grouped FUNCTION - Site for lymph production and filter for screening out harmful substances If substance can’t be destroyed, node becomes inflamed

Adenoids- tonsils on upper part of the throat Palatine sides of throat Masses of lymphatic tissue that produce lymphocytes and filter bacteria- they get smaller in size as person gets older 3 pairs: Adenoids- tonsils on upper part of the throat Palatine sides of throat Lingual back of tongue Say “aahhh” Why this is helpful?

Sac- like mass of lymphatic tissue Spleen Sac- like mass of lymphatic tissue Upper left abdominal cavity, just below diaphragm Form lymphocytes and monocytes Filters blood Stores large amounts of RBCs- contracts during vigorous exercise or loss of blood, to release RBCs Destroys or removes old or fragile RBCs Thymus Gland Upper, anterior thorax, above the heart Thymus is also considered an endocrine gland

Immunity The body’s ability to resist bacterial invasion and disease Antigen- substance stimulating formation of antibodies against itself Antibody- substance produced by the body that inactivates a specific foreign substance which has entered the body

Natural Immunity at birth, inherited and permanent. Includes: Unbroken skin Mucus and tears Blood phagocytes Local inflammation

2. Acquired Immunity- body’s reaction to invaders A) Passive Acquired Immunity - Acquired artificially by injecting antibodies to protect from a specific disease - Immediate immunity - Lasts 3-5 weeks - Used when someone exposed to meningitis, tetanus, infectious hepatitis - Mother provides newborn with passive acquired immunity with breast feeding

B) Active Acquired Immunity- lasts longer, two types -Natural Acquired Immunity- result of having had and recovered from a disease. For example, a child who has measles will usually not get it again - child’s body has manufactured antibodies. - Artificial Acquired Immunity- comes from being vaccinated Immunization- artificial resistance to a particular infection by artificial means Antigen injected into a person to stimulate production of antibodies

Standard Precautions Guidelines to be used in patient care setting Must be used when there is contact with blood, any body fluid, mucous membranes and non-intact skin Hand washing- the single most effective way to prevent infection 1. Wash hands often 2. Wash hands immediately after removing gloves, between patient contacts 3. Use a plain (non-antimicrobial) soap 4. Wash for a minimum of 20 seconds Gloves- worn when touching blood, body fluids, etc. Mask, eye protection, face shield and gown- during patient care activities that may generate splashes or sprays of blood, body fluids, etc. PPE Patient care equipment and linens- handle with care, don’t let it touch your clothing, and clean or discard appropriately.

Occupational Health and Bloodborne Pathogens Beware of needles! Never recap used needles Dispose of all needles and sharp objects in sharps container Use mouthpieces, resuscitation bags, or other ventilation devices as alternative to mouth-to-mouth resuscitation A patient who contaminates the environment should be in a private room or relatively isolated area Opportunistic Infection- an infection caused by pathogens Nosocomial infections – infections that occur in the hospital

Disorders of the Lymphatic System Adenitis- swelling in the lymph glands Tonsillitis Tonsils become infected, enlarged, and cause difficulty swallowing Surgery done in extreme cases Lymphadenitis- enlargement of the lymph nodes, occurs when infection is present and body is attempting to fight off the infection Hodgkin’s disease- cancer of the lymph nodes: painless swelling of lymph nodes is early symptom RX- chemotherapy and radiation Infectious Mononucleosis Caused by virus Common in young adults and children Spread by oral contact (kissing, sharing glasses, etc.) Symptoms- enlarged lymph nodes, fever, enlarged spleen, physical and mental fatigue, increased lymphocytes RX-bed rest

Hypersensitivity When the body’s immune system fails to protect itself again foreign material, and instead, the antibodies formed irritate certain body cells An abnormal response to a drug or allergen An allergen is an antigen that causes allergic responses. (Examples of allergens- ragweed, penicillin, bee stings, foods, etc.) Anaphylaxis Severe, sometimes fatal allergic reaction Antigen-antibody reaction stimulates a massive secretion of histamine Symptoms- breathing problems, headache, facial swelling, falling blood pressure, stomach cramps, and vomiting RX- adrenaline (epinephrine) AIDS/HIV Acquired Immunodeficiency Syndrome Caused by HIV or Human Immunodeficiency Virus Affects not only homosexual males but all populations The patient with AIDS cannot fight off cancers and most infections Three responses to HIV infection: AIDS ARC (AIDS related complex) Asymptomatic infection Screening tests for HIV/AIDS are available

1. AIDS Most severe type of HIV infection Subject to opportunistic infections- a healthy person would fight off these infections, but a person with AIDS has a compromised immune response. Symptoms of AIDS Prolonged fatigue Persistent fevers or night sweats Persistent, unexplained cough Thick coating in throat or on tongue Easy bruising, unexplained bleeding Appearance of purple lesions on mucous membranes or skin that don’t go away Chronic diarrhea Shortness of breath Unexplained lymphadenopathy Unexplained weight loss, 10 pounds or more, in less than 2 months Incubation period: 1 month to 12 years

2. AIDS-Related Complex (ARC) Has HIV but not AIDS and develops other conditions such as: Chronic diarrhea Chronic lymphadenopathy Unexplained weight loss If life threatening opportunistic infections develop, then individual is said to have AIDS Has HIV but no symptoms High risk groups for AIDS- everyone who participates in risky behaviors 3. Asymptomatic infection

Transmission of HIV by: Sex with someone who is HIV positive (How do you know?) Sharing needles with infected IV drug users At birth from infected mother Careless handling of patient body fluids/needle sticks HIV cannot be spread by: Casual contact Through air, feces, food, urine or water Coughing, sneezing, embracing, shaking hands and sharing eating utensils Prevention of HIV: Avoid risky behaviors Standard precautions