BSC 2086 01 Anatomy and Physiology II Spring 2013 11 The Lymphatic System 2012 Pearson Education Inc An Introduction to the Lymphatic System and Immunity Learning Outcomes 22 1 Distinguish between innate nonspecific and adaptive specific defenses and explain the role of lymphocytes in the immune response 22 2 Identify the major components of the lymphatic system describe the structure and functions of each component and discuss the importance of lymphocytes 2012 Pearson Education Inc An Introduction to the Lymphatic System and Immunity Microscopic organisms that cause disease Pathogens Viruses Bacteria Fungi Parasites 2012 Pearson Education Inc Each attacks in a specific way 22 1 Overview of the Lymphatic System The Immune System Immunity The ability to resist infection and disease All body cells and tissues involved in production of immunity not just lymphatic system Two main types of defenses 1 Nonspecific defenses 2 Specific defenses 2012 Pearson Education Inc 22 1 Overview of the Lymphatic System 1 Nonspecific Defenses Block or attack any potential infectious organism Cannot distinguish one attack from another 1 Specific Defenses Lymphocytes pathogen 2012 Pearson Education Inc Part of the immune response Identify attack and develop immunity to a specific 22 1 Overview of the Lymphatic System The Lymphatic System Protects us against disease Lymphatic system cells respond to Environmental pathogens Toxins Abnormal body cells such as cancers 2012 Pearson Education Inc 22 2 Structures of Body Defenses Organization of the Lymphatic System 1 Lymph proteins system A fluid similar to plasma but does not have plasma 1 Lymphatic vessels lymphatics Carry lymph from peripheral tissues to the venous 1 Lymphoid tissues and lymphoid organs 2 Lymphocytes phagocytes and other immune system cells 2012 Pearson Education Inc Figure 22 1 An Overview of the Lymphatic System Part 1 of 2 Lymphatic Vessels and Lymph Nodes Cervical lymph nodes Thoracic duct Right lymphatic duct Axillary lymph nodes Lymphatics of mammary gland Cisterna chyli Lymphatics of upper limb Lumbar lymph nodes 2012 Pearson Education Inc Lymph Lymphocyte Lymphoid Tissues and Organs Tonsil Thymus Spleen Mucosa associated lymphoid tissue MALT in digestive respiratory urinary and reproductive tracts Figure 22 1 An Overview of the Lymphatic System Part 2 of 2 Lymphoid Tissues and Organs Appendix Lymphatic Vessels and Lymph Nodes Inguinal lymph nodes Lymphatics of lower limb 2012 Pearson Education Inc 22 2 Structures of Body Defenses Function of the Lymphatic System To produce maintain and distribute lymphocytes Lymphocytes Detect problems Travel into site of injury or infection Lymphocyte Production Lymphocytes are produced In lymphoid tissues e g tonsils In lymphoid organs e g spleen thymus In red bone marrow 2012 Pearson Education Inc 22 2 Structures of Body Defenses Lymphocyte Circulation From blood to interstitial fluid through capillaries Returns to venous blood through lymphatic vessels The Circulation of Fluids From blood plasma to lymph and back to the venous system Transports hormones nutrients and waste products 2012 Pearson Education Inc 22 2 Structures of Body Defenses Lymphatic Vessels vessels that carry lymph Lymphatic system begins with smallest vessels Lymphatic capillaries Differ from blood capillaries in four ways 1 Start as pockets rather than tubes dead ends 2 Have larger diameters 3 Have thinner walls 4 Flat or irregular outline in sectional view 2012 Pearson Education Inc Figure 22 2a Lymphatic Capillaries Smooth muscle Arteriole Endothelial cells Lymphatic capillary Venule Interstitial fluid Lymph flow Blood capillaries Loose connective tissue The interwoven network formed by blood capillaries and lymphatic capillaries 2012 Pearson Education Inc Figure 22 2b Lymphatic Capillaries Lymphocyte Incomplete basement membrane Lymph flow Loose connective tissue To larger lymphatics Interstitial fluid Lymphatic capillary Interstitial fluid Blood capillary A sectional view indicating the movement of fluid from the plasma through the tissues as interstitial fluid and into the lymphatic system as lymph 2012 Pearson Education Inc 22 2 Structures of Body Defenses Lymphatic Capillaries Endothelial cells loosely bound together with overlap Overlap acts as one way valve Allows fluids solutes viruses and bacteria to enter Prevents return to intercellular space Edema of tissue causes overlapping endothelial cells to separate allowing fluid into the lymphatic capillaries 2012 Pearson Education Inc 22 2 Structures of Body Defenses Lymph Flow From lymphatic capillaries to larger lymphatic vessels containing one way valves Lymphatic vessels travel with veins Transports lymph to right lymphatic duct and left thoracic duct that is connected to the subclavian vein to combine with venous return Lacteals special lymphatic capillaries in small intestine Transport lipids absorbed from digestive tract 2012 Pearson Education Inc Figure 22 3a Lymphatic Vessels and Valves Vein Artery Lymphatic vessel Lymphatic valve From lymphatic capillaries 2012 Pearson Education Inc Artery Vein Lymphatic vessel Toward venous system Figure 22 3b Lymphatic Vessels and Valves Lymphatic valve Lymphatic vessel Like valves in veins each lymphatic valve consists of a pair of flaps that permit movement of fluid in only one direction 2012 Pearson Education Inc Lymphatic vessel and valve LM 63 Figure 22 4a The Relationship between the Lymphatic Ducts and the Venous System Drainage of right lymphatic duct Drainage of thoracic duct Note The right lymphatic duct drains the upper right thoracic region head and arm while the left thoracic duct drains the rest of the body The thoracic duct carries lymph originating in tissues inferior to the diaphragm and from the left side of the upper body The smaller right lymphatic duct delivers lymph from the rest of the body 2012 Pearson Education Inc Figure 22 4b The Relationship between the Lymphatic Ducts and the Venous System Part 1 of 2 Brachiocephalic veins Right internal jugular vein Right jugular trunk Right lymphatic duct Right subclavian trunk Right subclavian vein Right bronchomediastinal trunk Superior vena cava cut Azygos vein Rib cut Inferior vena cava cut Right lumbar trunk 2012 Pearson Education Inc The thoracic duct empties into the left subclavian vein The right lymphatic duct drains into the right subclavian vein Figure 22 4b The Relationship between the Lymphatic Ducts and the Venous System Part 2 of 2
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