Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Seventh Edition Elaine N. Marieb Chapter 14 The Lymphatic System and Body Defenses

The Lymphatic System Slide 12.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Two parts  Lymphatic vessels  Lymphoid tissues and organs  Lymphatic system functions  Transport fluids back to the blood  Play essential roles in body defense and resistance to disease  Absorb digested fat at the intestinal villi

Lymphatic Characteristics Slide 12.2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymph – excess tissue fluid carried by lymphatic vessels  Properties of lymphatic vessels  One way system toward the heart  No pump  Lymph moves toward the heart  Milking action of skeletal muscle  Rhythmic contraction of smooth muscle in vessel walls

Lymphatic Vessels Slide 12.3b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.1

Lymphatic Vessels Slide 12.4a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymphatic collecting vessels  Collects lymph from lymph capillaries  Carries lymph to and away from lymph nodes  Returns fluid to circulatory veins near the heart Figure 12.2

Lymph Slide 12.5a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Materials returned to the blood  Water  Blood cells  Proteins  Harmful materials that enter lymph vessels  Bacteria  Viruses  Cancer cells  Cell debris

Lymph Nodes Slide 12.6a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  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

Lymph Nodes Slide 12.6b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.3

Other Lymphoid Organs Slide 12.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Several other organs contribute to lymphatic function  Spleen  Thymus  Tonsils  Peyer’s patches Figure 12.5

The Spleen Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Located on the left side of the abdomen  Filters blood  Destroys worn out blood cells  Forms blood cells in the fetus  Acts as a blood reservoir

The Thymus Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Located low in the throat, overlying the heart  Functions at peak levels only during childhood  Produces hormones (like thymosin) to program lymphocytes

Tonsils Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Small masses of lymphoid tissue around the pharynx  Trap and remove bacteria and other foreign materials  Tonsillitis is caused by congestion with bacteria

Peyer’s Patches Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Found in the wall of the small intestine  Resemble tonsils in structure  Capture and destroy bacteria in the intestine

Body Defenses Slide 12.15a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The body is constantly in contact with bacteria, fungi, and viruses (pathogens)  The body has two defense systems for foreign materials  Nonspecific defense system  Mechanisms protect against a variety of invaders  Responds immediately to protect body from foreign materials

Body Defenses & Nonspecific Body Defenses Slide 12.15b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Specific defense system  Specific defense is required for each type of invader  Also known as the immune system  Body surface coverings  Intact skin  Mucous membranes  Specialized human cells  Chemicals produced by the body

Surface Membrane Barriers – First Line of Defense Slide 12.17a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The skin  Physical barrier to foreign materials  pH of the skin is acidic to inhibit bacterial growth  Sebum is toxic to bacteria & vaginal secretions are very acidic  Stomach mucosa  Secretes hydrochloric acid & protein-digesting enzymes  Saliva and lacrimal fluid contain lysozyme  Mucus traps microogranisms in digestive and respiratory pathways

Defensive Cells Slide 12.18a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Phagocytes (neutrophils and macrophages)  Engulfs foreign material into a vacuole  Enzymes from lysosomes digest the material Figure 12.6b

Macrophage attacking e-coli. Macrophage attacking e-coli.

Defensive Cells Slide 12.18b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Natural killer cells  Can lyse and kill cancer cells  Can destroy virus- infected cells Figure 12.6b

Inflammatory Response - Second Line of Defense Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Triggered when body tissues are injured  Produces four cardinal signs  Redness  Heat  Swelling  Pain  Results in a chain of events leading to protection and healing

Functions of the Inflammatory Response Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Prevents spread of damaging agents  Disposes of cell debris and pathogens  Sets the stage for repair

Steps in the Inflammatory Response Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.7

Antimicrobial Chemicals Slide 12.22a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Complement  A group of at least 20 plasma proteins  Activated when they encounter and attach to cells  Damage foreign cell surfaces  Will rupture or lyse the foreign cell membrane Figure 12.8

Antimicrobial Chemicals Slide 12.22c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Interferon  Secreted proteins of virus-infected cells  Bind to healthy cell surfaces to inhibit viruses binding

Interferons are a family species-specific proteins synthesized by eukaryotic cells in response to viruses and a variety of natural and synthetic stimuli. There are several different interferons commonly used as therapeutics, termed alpha, beta, and gamma. These peptides are used to treat hairy cell leukemia, AIDS-related Kaposi's sarcoma, laryngeal papillomatosis, genital warts, and chronic granulomatous disease. Side effects include black tarry stools, blood in the urine, confusion, and loss of balance.

Fever Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Abnormally high body temperature  Hypothalmus heat regulation can be reset by pyrogens (secreted by white blood cells)  High temperatures inhibit the release of iron and zinc from liver and spleen needed by bacteria  Fever also increases the speed of tissue repair

Specific Defense: The Immune System – Third Line of Defense Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antigen specific – recognizes and acts against particular foreign substances  Systemic – not restricted to the initial infection site  Has memory – recognizes and mounts a stronger attack on previously encountered pathogens

Types of Immunity Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Humoral immunity  Antibody-mediated immunity  Cells produce chemicals for defense  Cellular immunity  Cell-mediated immunity  Cells target virus infected cells

Antigens (Nonself) Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Any substance capable of exciting the immune system and provoking an immune response  Examples of common antigens  Foreign proteins  Nucleic acids  Large carbohydrates  Some lipids  Pollen grains  Microorganisms

Self-Antigens Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Human cells have many surface proteins  Our immune cells do not attack our own proteins  Our cells in another person’s body can trigger an immune response because they are foreign  Restricts donors for transplants

Allergies Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Many small molecules (called haptens or incomplete antigens) are not antigenic, but link up with our own proteins  The immune system may recognize and respond to a protein-hapten combination  The immune response is harmful rather than protective because it attacks our own cells

Cells of the Immune System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymphocytes  Originate from hemocytoblasts in the red bone marrow  B lymphocytes become immunocompetent in the bone marrow  T lymphocytes become immunocompetent in the thymus  Macrophages  Arise from monocytes  Become widely distributed in lymphoid organs

Activation of Lymphocytes Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.9

Humoral (Antibody-Mediated) Immune Response Slide 12.31a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  B lymphocytes with specific receptors bind to a specific antigen  The binding event activates the lymphocyte to undergo clonal selection  A large number of clones are produced (primary humoral response)  Most B cells become plasma cells  Produce antibodies to destroy antigens  Activity lasts for four or five days  Some B cells become long-lived memory cells (secondary humoral response)

Humoral Immune Response Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.10

Active Immunity Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Your B cells encounter antigens and produce antibodies  Active immunity can be naturally or artificially acquired Figure 12.12

Passive Immunity Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antibodies are obtained from someone else  Conferred naturally from a mother to her fetus  Conferred artificially from immune serum or gamma globulin  Immunological memory does not occur  Protection provided by “borrowed antibodies”

Antibodies (Immunoglobulins) (Igs) Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Soluble proteins secreted by B cells (plasma cells)  Carried in blood plasma  Capable of binding specifically to an antigen

Antibody Classes Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antibodies of each class have slightly different roles  Five major immunoglobulin classes – (Do Not Need to know!)  IgM – can fix complement  IgA – found mainly in mucus  IgD – important in activation of B cell  IgG – can cross the placental barrier  IgE – involved in allergies

Cellular (Cell-Mediated) Immune Response Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antigens must be presented by macrophages to an immunocompetent T cell (antigen presentation)  T cells must recognize nonself and self (double recognition)  After antigen binding, clones form as with B cells, but different classes of cells are produced

Cellular (Cell-Mediated) Immune Response Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.15

T Cell Clones Slide 12.44a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cytotoxic T cells  Specialize in killing infected cells  Insert a toxic chemical (perforin)  Helper T cells  Recruit other cells to fight the invaders  Interact directly with B cells  Suppressor T cells  Release chemicals to suppress the activity of T and B cells  Stop the immune response to prevent uncontrolled activity  A few members of each clone are memory cells

Summary of the Immune Response Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.16

Organ Transplants and Rejection Slide 12.46a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Major types of grafts  Autografts – tissue transplanted from one site to another on the same person (ideal donors)  Isografts – tissue grafts from an identical person (ideal donors)  Allografts – tissue taken from an unrelated person (more successful with a closer tissue match)  Xenografts – tissue taken from a different animal species (never successful)

Disorders of Immunity: Immunodeficiencies Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Production or function of immune cells or complement is abnormal  May be congenital or acquired  Includes AIDS – Acquired Immune Deficiency Syndrome

Disorders of Immunity: Autoimmune Diseases Slide 12.50a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The immune system does not distinguish between self and nonself  The body produces antibodies and sensitized T lymphocytes that attack its own tissues

Disorders of Immunity: Autoimmune Diseases Slide 12.50b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Multiple sclerosis – white matter of brain and spinal cord are destroyed  Myasthenia gravis – impairs communication between nerves and skeletal muscles  Juvenile diabetes – destroys pancreatic beta cells that produce insulin  Rheumatoid arthritis – destroys joints  Systemic lupus erythematosus (SLE) – affects kidney, heart, lung and skin  Glomerulonephritis – impairment of renal function