ELAINE N. MARIEB EIGHTH EDITION 12 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY PART A The Lymphatic System and Body Defenses

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Lymphatic System  Lymphatic system functions  Transport fluids back to the blood  Role in body defense, disease resistance  Lymph: excess tissue fluid  Lymphatic vessels: carry lymph toward heart  Lymph materials returned to the blood-  Water, blood cells, proteins  Harmful materials that enter lymph vessels  Bacteria, Viruses, Cancer cells, Cell debris

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lymph Nodes  Lymph Nodes:  Filter lymph before it is returned to the blood  Defense cells within lymph nodes  Macrophages – engulf and destroy foreign substances  Lymphocytes – provide immune response to antigens

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lymph Nodes Figure 12.3

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Other Lymphoid Organs  Spleen: filters blood, destroys old RBCs.  Thymus: Located in throat, over heart. Programs lymphocytes.  Tonsils: lymph tissue of pharynx, traps & removes bacteria. Tonsillitis: bacteria congestion  Peyer’s patches: Capture and destroy bacteria in the intestine  Appendix: help produce antibodies Figure 12.5

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Body Defenses  The body is constantly in contact with bacteria, fungi, and viruses. Body secretes chemicals like lysozyme, acid, and enzymes to kill invaders; mucous to trap invaders.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Defensive Cells  Phagocytes (neutrophils and macrophages)  Engulfs foreign material  Lysosome enzymes digest material  Interferon  Bind to healthy cell surfaces to inhibit viruses binding Figure 12.7a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Inflammation- Second Line of Defense  Inflammation: Triggered when body tissues are injured.  Signs- Redness, Heat, Swelling, Pain  Results in a chain of events leading to protection and healing of tissue  Fever: Abnormally high body temperature.  High temperatures inhibit the release of iron and zinc from liver and spleen needed by bacteria. Fever also increases the speed of tissue repair.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antigens (Nonself)  Antigen: any foreign substance capable of triggering immune system  Examples of common antigens:  Foreign proteins, pollen grains, microorganisms  Our immune cells attack specific antigens  Has memory – recognizes and mounts a stronger attack on previously encountered pathogens  Allergies: molecules that immune system interprets as foreign, end up attacking our own cells

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cells of the Immune System  Lymphocytes (B and T lymphocytes)  B lymphocytes: bind to a specific antigen, Produce antibodies (immunoglobulins Igs) to destroy antigens. Some become memory cells.  T lymphocytes: Antigens must be presented by macrophages to T cell. Killer T cells destroy it.  Macrophages  Arise from monocytes  Become widely distributed in lymphoid organs

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cellular (Cell-Mediated) Immune Response Figure 12.17

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders of Immunity: Immunodeficiencies  Immunodeficiency: immune cells abnormal, not enough. Includes AIDS- Acquired Immune Deficiency Syndrome  Autoimmune Disease: cells cannot tell self and non-self apart and attacks own cells. Includes Multiple Sclerosis (MS), arthritis