L8 Lymphatic System PDF

Anatomy of the Lymphatic System Department of human Anatomy and Embryology Faculty of Medicine Mansoura National University, Egypt  Intended Learning Outcomes (ILOs) 1. Enumerate the components of the lymphatic system. 2. Recognize the features of lymph 3. Describe the...

Anatomy of the Lymphatic System Department of human Anatomy and Embryology Faculty of Medicine Mansoura National University, Egypt  Intended Learning Outcomes (ILOs) 1. Enumerate the components of the lymphatic system. 2. Recognize the features of lymph 3. Describe the lymphatic drainage of the body in vessels. 4. Define and identify the different lymphoid tissues of the body 5. Identify the different lymphoid organs and their functions  Agenda 1. What are the components of the lymphatic system? 2. What are the features of the lymph? 3. What are the major lymphatic vessels of the body? 4. What are the lymphoid tissues of the body? 5. What are the lymphoid organs of the body and their functions?  Components of the Lymphatic System Components: 1.Lymph 2.Lymphatic vessels 3.Lymphoid tissues 4.Lymphoid organs Functions: 1.Part of the immune system 2.Complementary to the circulatory system  Lymph A clear fluid that escapes from capillaries by filtration into tissue spaces It returns to the blood stream via Lymphatic Vessels  Lymphatic Vessels Features: Begin as blind-ended capillaries, which unite to form lymphatic vessels Have multiple valves to allow the passage of lymph in only one direction Lymphatic vessels are absent in some tissues, e.g. central nervous system, bone marrow, teeth and avascular tissues (e.g. cartilage) All lymphatic vessels of the body unite to form two large lymphatic ducts: Thoracic Duct and Right Lymphatic duct  Lymphatic Vessels Right Lymphatic duct drains: Right side of the head and neck Right upper limb Right side of the thorax  Thoracic duct drains: the rest of the body The two ducts terminate at the junction of the internal jugular vein and subclavian vein  Quiz What vessels have valves? A) Arteries and veins B) Arterioles and venules C) Capillaries and lymphatic vessels D) Veins and capillaries E) Lymphatic vessels and veins Answer: E  Quiz What area does NOT have lymphatic vessels? A) Teeth B) Upper limb C) Foot D) Abdomen E) Peripheral nervous system Answer: A  Lymphoid Tissues Tissues that contain aggregations of lymphocytes Include: MALT and tonsils A. MALT (Mucosal Associated Lymphoid Tissues): in the walls of tubular organs B. Tonsils: non-encapsulated aggregations of lymphoid tissue located within the pharynx. Include: Pharyngeal, tubal, palatine and lingual tonsils  Lymphoid Organs Encapsulated aggregations of lymphocytes Include: Lymph nodes, spleen and thymus gland Spleen A lymphoid organ located in the upper left part of the abdomen Functions: 1. Destroys old RBCs 2. Acts as a Blood reservoir 3. A part of the immune system  Lymph nodes Small, kidney-shaped lymphoid organs situated along the course of lymph vessels Present in groups in different body regions (e.g. cervical, axillary, inguinal, etc) Lymph enters the lymph node through afferent vessels and leaves it through efferent vessels Function: filtration of lymph and also contain lymphocytes, which are important for immunity Become enlarged when infected by microorganisms and when infiltrated by malignant cells  Lymphoid Organs Thymus Gland A lymphoid organ located in the thoracic cavity behind the sternum Increases in size during childhood reaching its maximum size at puberty then it begins to decrease in size and activity (involution) Function: T-lymphocyte maturation  Quiz What differentiates tonsils from lymphoid organs? A) Tonsils have a capsule B) Tonsils do NOT have a capsule C) Tonsils break down old RBCs D) Tonsils are responsible for T cell maturation E) Tonsils are grouped in different body regions (cervical, axillary, inguinal, etc) Answer: B