Functions & Structures

 Absorb fats & fat soluble vitamins from the digestive system and transport them to the cells  Return cellular waste products and excess fluid from the tissues to the circulatory system  Serve as an important part of the immune system

 Lymph fluid  Lymph vessels ◦ Lymph capillaries ◦ Lymphatic ducts ◦ Valves ◦ Lacteals  Specialized lymph capillaries located in the villi of the small intestine. There fats and fat-soluble vitamins are absorbed and carried into the bloodstream

 Lymph Nodes ◦ Produce lymphocytes and filter harmful substances from lymph as it flows through the nodes  Tonsils ◦ Adenoids, Palatine tonsils, & Lingual tonsils ◦ Study the chart on page 108 about the different locations of the tonsils

 Vermiform Appendix ◦ Lymphatic tissue that hangs from the lower portion of the cecum of the large intestine  Peyer’s patches ◦ Small bundles of lymphatic tissue located on the walls of the ileum of the small intestine ◦ Where lymphocytes form and undergo further maturation and differentiation

 Cont.  Spleen ◦ Filters microorganisms and foreign material from blood ◦ Forms specialized WBCs ◦ Hemolytic function ◦ Stores extra erythrocytes  Thymus – plays a role in endocrine & immune systems

 Protects the body from harmful substances ◦ Pathogens ◦ Allergens ◦ Toxins ◦ Malignant cells

 First line of defense ◦ Intact skin – physical barrier ◦ Respiratory system ◦ Digestive system ◦ Lymphatic system

 Immune response ◦ Antigen?  Any substance the body regards as foreign ◦ Antibody – disease fighting protein created by the immune system in response to the presence of that specific antigen ◦ Antigen-antibody reaction

 Specialized cells ◦ Lymphocytes-  White Blood cells that specialize so they can attack specific microorganisms.  Mature in the lymphatic tissue ◦ B cells  Immunoglobulin – synonym for antibody, different types eg. M, G, A, E, D  Plasma cells – B cells turn into these when exposed to their antigen. They then make and secrete antibodies coded to match the antigen.

 T cells  Regulatory T cells coordinate immune defenses. Cytotoxic T cells kill infected cells on contact.  Interferon  Produced by T cells. A family of proteins released by cells when invaded by a virus. Causes noninfected cells to form an antiviral protein that slows or stops viral multiplication. Grouped into 3 categories: alpha, beta, and gamma  Lymphokines  Phagocyte – eat invading antigens  Macrophage

 Immunity ◦ Natural  Passed from mother to fetus before birth. After birth additional immunity is passed through breast milk ◦ Acquired  Obtained by the development of antibodies during an attack of an infectious disease. As an example, after having chickenpox antibodies are present against it. ◦ Artificial  Acquired through vaccination. Also known as immunization.

 Immune system response factors ◦ Health ◦ Age ◦ Heredity ◦ Opportunistic infection

 Bacteria – one celled microscopic organisms ◦ Bacilli – rod-shaped, spore forming ◦ Rickettsia – live in lice, fleas, ticks, and mites. Rocky Mountain spotted fever transmitted by infected tick bites ◦ Spirochete – spiral-shaped, have flexible walls and are capable of movement. Lyme disease transmitted by deer tick bites. ◦ Staphylococci – form irregular groups or clusters. Bacterial pneumonia is this type of bacteria ◦ Streptococci – form a chain

 Fungus - Simple parasitic plant ◦ Aspergillosis caused by Aspergillus  Yeast - Type of fungus ◦ Moniliasis – infection of the skin or mucous membranes. Usually localized in the mouth or the vagina  Parasites – plant or animal that lives on or within another living organism at the expense of that organism ◦ Malaria – transmitted by the bite of an infected mosquito

 Viruses – very small infectious agents that live only by invading cells ◦ Cytomegalovirus (CMV) ◦ Mononucleosis ◦ Mumps ◦ Rubella ◦ Herpes zoster – Shingles. Caused by the chickenpox virus that remains dormant in a nerve and is reactivated later ◦ Varicella – VZV – Chickenpox. Caused by a herpes virus ◦ Measles – Koplik’s spots, small red spots with blue- white centers that appear on the lining of the mouth. ◦ Rabies

 Antibiotics- useless on viruses ◦ Bactericide – kills the bacteria, ◦ Bacteriostatic – inhibits, or slows down, the growth of bacteria  antivirals