lymphatic system and immunity human anatomy and physiology ii oklahoma city community college dennis...
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Lymphatic System and Immunity
Human Anatomy and Physiology II
Oklahoma City Community College
Dennis Anderson
Functions of Lymphatic System
• Drain fluid from around cells
• Absorb fat from intestines
• Circulate lymph
• Filter lymph
• Immunity
Lymphatic Vessels
• Transport lymph
• Lymph is returned to the circulatory system at either the right or left subclavian veins
Causes of Edema
• Blockage of lymphatic system
• Increased pressure in veins
• Lack of albumin– Decreases fluid returning to blood capillaries
by osmosis
• Inflammation
Steroid Hormones
• Hydrocortisone, cortisone and others
• Depress inflammation
• Used to treat inflammatory diseases– Rheumatoid arthritis
Antigens
• Molecules often found in the membrane of cells
• Antigens of foreign cells stimulate an immune response
Self Antigens• Antigens of our own cells
• Do not cause an immune response in our body– Usually cause an immune response in another
person
• MHC proteins– Major Histocompatibility Complex
Cells of the Immune System
• APCs– Antigen-presenting cells
• B cells– B lymphocytes
• T cells– T lymphocytes
Antigen-Presenting Cells
• Macrophages• Engulf foreign cells and attach the cells antigens on their
MHC proteins
Antigen-Presenting CellAPC
• Macrophages and other cells
• Engulfs and digests foreign cells
• Present antigens on MHC proteins to T cells
B Cells
• Lymphocytes that react directly with antigens
• Require stimulation from Helper T Cells
• Offspring become– Plasma cells– Memory B cells
• Humoral Immunity
Helper T Cell
• Reacts with antigen from APC
• Stimulates Cytotoxic T Cells and B Cells– Secretes Interleukin II
Cytotoxic T Cells• Activated by antigens
on any body cell• Require stimulation
from Helper T Cells• Destroys body cells
infected with viruses• Destroys cancer cells• Cellular Immunity
Memory Cells
• T Cells and B Cells
• Remember antigen
• React to a second invasion of an antigen more rapidly
Cytokines
• Chemicals used in cellular immunity• Interleukin I
– Produced by macrophages– Stimulates helper T cells
• Interleukin II– Produced by helper T cells
• Perforin– Causes lysis of target cell
Acquired Immune Deficiency Syndrome
• HIV Virus
• Attacks and destroys Helper T Cells– Depresses humoral and cellular immunity
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