Lymphatic and Immune system Chapter 17

Lymphatic System System consists ofSystem consists of –Lymph fluid –Lymphatic vessels –Structures and organs consisting of lymphatic tissue –Red bone marrow –Lymphocytes Tortora Pages

Functions of Lymphatic System Draining interstitial fluidDraining interstitial fluid Transporting lipids and lipid soluble vitamins A,D, E, and KTransporting lipids and lipid soluble vitamins A,D, E, and K Carries out immune responsesCarries out immune responses Tortora Page 456

Lymphatic and Interstitial fluid Same fluid - different areas.Same fluid - different areas. –Interstitial fluid bathes cells. –Lymphatic fluid is I.F. in lymphatic vessels. Contains same materials as plasma except no proteinsContains same materials as plasma except no proteins

Lymphatic capillaries –Lie between cells –Open –Collect interstitial fluid. –Fluid moves due to pressure. –Flaps open, allow fluid in, then close Tortora 456

Lymphatic Vessels Lymphatic vesselsLymphatic vessels –Carry lymph fluid –Similar structure as veins with –Thinner walls & more valves. valves. –Skeletal and muscular pumps move it towards the heart. Tortora pg 457

Return to veins Lymphatic fluid is returned to circulatory system via the jugular & subclavian veinsLymphatic fluid is returned to circulatory system via the jugular & subclavian veins 20 L of plasma become IF every day20 L of plasma become IF every day 17 L goes back to heart via the veins17 L goes back to heart via the veins 3 L becomes lymph3 L becomes lymphTortora

Lymph Nodes –Located along lymphatic vessels. –Arranged in groups. –Afferent vessel leads to node. –Efferent leads away. –Valves do not let lymph fluid move backwards. Tortora pg

Lymphatic nodes –600 located in the body –Concentrated at axillae, mammary glands, throat and groin –Foreign materials are filtered and destroyed in nodes. –Macrophages destroy by phagocytosis –Lymphocytes destroy by a variety of immune responses Tortora pg 458

Macrophages Two cross sections of a lymph node: macrophages, which appear as red in the top image, are sticky cells that act like flypaper, trapping viruses and bacteria when they enter the lymph node. Green and blue show other structural elements of the node. In the bottom picture, B cells are red and the structural elements of the node are in green and blue

Swollen lymph nodes

Tonsils & spleen Tonsils:Tonsils: –Large nodules grouped together. –Contains T and B lymphocytes. SpleenSpleen –Largest mass of lymphatic tissue. –Stores blood. –Stores 1/3 rd of the body’s platelets –Destroys broken RBCs & platelets.

Thymus gland –Contains T cells, dendritic cells, and macrophages. –Immature T cells arrive here from the red bone marrow. –2% “graduate” to be mature T cells. –Mature T cells leave the thymus via the blood, are carried to the lymph nodes, spleen, and other lymphatic tissues. Tortora 458

Lymph Circulation Fluid from plasma of blood.Fluid from plasma of blood. Interstitial fluid.Interstitial fluid. Lymph Vessels and nodesLymph Vessels and nodes –Lymphatic capillaries –Lymphatic vessels. –Lymph nodes. Back to plasma.Back to plasma. Thursday 5/8/03 Pages

Lymph Circulation Lymph fluid is moved by;Lymph fluid is moved by; –Skeletal muscles compressing vessels. –Valves insure one way flow. EdemaEdema –Fluid gain in the interstitial spaces. –Can be due to blocked lymphatic vessels or nodes. Thursday 5/8/03 Pages

Innate Resistance to Disease Pathogens are disease causing organisms.Pathogens are disease causing organisms. Pathogens produce toxins or toxic waste products.Pathogens produce toxins or toxic waste products. Your ability to ward off pathogens is resistance.Your ability to ward off pathogens is resistance. Lack of resistance is susceptibility.Lack of resistance is susceptibility.

Skin & Mucous Membranes Skin is 1st defense against pathogens.Skin is 1st defense against pathogens. Mechanical factorsMechanical factors –Many layers of epithelial cells. –Role of keratin. –Role of Mucus membranes. –Mucus –Cilia –Role of lacrimal apparatus –Role of Saliva

Skin & Mucous Membranes Chemical Factors in skin and mucous membranes:Chemical Factors in skin and mucous membranes: –Oil glands secrete sebum. –Perspiration –Lysozymes –Gastric juice –Vaginal Secretions.

Defenses Against Microbes Second line of defense:Second line of defense: –Interferon Proteins produced by cells infected by viruses.Proteins produced by cells infected by viruses. Bind to receptor sites of other cells.Bind to receptor sites of other cells. –Complement Group of about 20 proteins.Group of about 20 proteins. Found in the plasma of blood.Found in the plasma of blood. Inhance immune system.Inhance immune system. Monday 5/12/03 Pages

Defenses Against Microbes Natural killer cellsNatural killer cells –Type of lymphocyte. –Ability to kill microbes and some cancer cells. –Located in spleen, lymph nodes, bone marrow, and blood. PhagocytesPhagocytes –Macrophages are monocytes that morph. Wandering and fixed.Wandering and fixed. –Neutrophils HiHi Monday 5/12/03 Pages

Phagocytosis ChemotaxisChemotaxis –Phagocytes move towards higher concentration of chemicals. AdherenceAdherence –Phagocytes attach to microbe. –Role of complement. IngestionIngestion –Pseudopod surrounds microbe. –Phagocytic vesicle is formed. –Vesicle fuses to lysosome. –Microbe is digested. –Wastes are released by exocytosis.

Inflammation Caused by pathogens, abrasions, chemical irritations.Caused by pathogens, abrasions, chemical irritations. SymptomsSymptoms –Redness –Pain –Heat –Swelling

Inflammation Stages of inflammationStages of inflammation –Vasodilation & increased permeability of blood vessels. –Phagocyte migration. Usually within an hour.Usually within an hour. Chemotaxis & emigrationChemotaxis & emigration RepairRepair

Fever The hypothalamic thermostat resets to raise body temp. Reason: higher temps inhibit antigen replication, but speeds up interferon and body repair

Innate and Adaptive Immunity Innate immunity is a generalized responseInnate immunity is a generalized response Adaptive immunity refers to “specific” response to certain pathogens.Adaptive immunity refers to “specific” response to certain pathogens. An antigen is any substance that triggers an immune response.An antigen is any substance that triggers an immune response. The immune system carries out immune responses to antigensThe immune system carries out immune responses to antigens Self-tolerance is when a body does not attack its own tissues and chemicals. Lack of self tolerance results in autoimmune diseases.Self-tolerance is when a body does not attack its own tissues and chemicals. Lack of self tolerance results in autoimmune diseases.

2 forms of adaptive immunity –Cell mediated immunity: Cells directly attack a specific antigen (pathogens)Cells directly attack a specific antigen (pathogens) –Antibody mediated immunity: Antibodies are produced to attack specific antigen.Antibodies are produced to attack specific antigen. –Both use mature T and B cells –2 types work together to remove infection

T Cells and Cell Mediated Immunity Recognizing self from nonself :MHCsRecognizing self from nonself :MHCs –Major histocompatibility complex proteins recognize non-self antigens –Role of MHCs in transplants T Cells destroy antigens:T Cells destroy antigens: –Macrophages present antigen to T cells. –T cells sensitize. –T cells clone. –Lyse infected cells

Antibodies and antigens Antigens can be –Whole pathogens –Toxins –Parts of pathogens Antigens + interleukin- 2 induce plasma cells to secrete proteins called antibodies (immunoglobulins)Antigens + interleukin- 2 induce plasma cells to secrete proteins called antibodies (immunoglobulins) Shaped like a “Y”Shaped like a “Y” One arm is always the same.One arm is always the same. Other 2 arms are specifically shaped to antigen.Other 2 arms are specifically shaped to antigen. Tortora Pages

Antibody action Antibodies travel to the infection site, bind to the antigen, and inactivate it.Antibodies travel to the infection site, bind to the antigen, and inactivate it.

How Antibodies affect antigens Neutralize the antigen toxinsNeutralize the antigen toxins Immobilize bacteria.Immobilize bacteria. Agglutination- antigens are stuck togetherAgglutination- antigens are stuck together

Memory cells –Converted B lymphocytes –B lymphocytes were shown the antigen by macrophages. –B cells now recognize antigen. –Some B cells become memory cells

B Cells and Antibody- Mediated immunity Long-lasting antibodies and lymphocytes “remember” the invading antigenLong-lasting antibodies and lymphocytes “remember” the invading antigen If the body is ever re-exposed, it will launch a swift attackIf the body is ever re-exposed, it will launch a swift attack Primary responsePrimary response –Slower to develop Secondary responseSecondary response –Much faster and stronger. Tortora Pages

Primary and secondary response

Vaccines and immunological memory Vaccines contain weakened, killed microbes or parts of microbes. Without getting sick, your body launches an immune response, activating B and T cells If you are ever exposed, your body will quickly remove the antigen. Some vaccines need “booster shots” to remain effective ( tetanus)

Types of Immunity 1.Naturally acquired active immunity. Response to pathogens in every day life.Response to pathogens in every day life. 2.Naturally acquired passive immunity. Natural transfer of resistance. Nursing baby.Natural transfer of resistance. Nursing baby. 3.Artificially acquired active immunity. Acquired through vaccinations.Acquired through vaccinations. 4.Artificially acquired passive immunity. Intravenous injection of antibodies.Intravenous injection of antibodies.