Lymphatic System Anatomy PDF

Lymphatic System Anatomy Lymph Tissue fluid (interstitial fluid) that enters the lymphatic vessels Formation And Transport Of Tissue Fluid Lymphatic System Is a drainage system accessory to venous system Larger particles that escape into tissue fluid can only be removed via lymphatic system Function...

Lymphatic System Anatomy Lymph Tissue fluid (interstitial fluid) that enters the lymphatic vessels Formation And Transport Of Tissue Fluid Lymphatic System Is a drainage system accessory to venous system Larger particles that escape into tissue fluid can only be removed via lymphatic system Functions 245 Reabsorbs excess interstitial fluid: returns it to the venous circulation maintain blood volume levels prevent interstitial fluid levels from rising out of control. Transport dietary lipids: lacteals drain into larger lymphatic vessels eventually into the bloodstream. Lymphocyte development, and the immune response. Components of the Lymphatic System 246 Lymph Lymphatic Vessels Lymphatic Capillaries Lymphatic Vessels Lymphatic Trunks Lymphatic Ducts Lymphatic Organs Thymus Lymph Nodes Spleen Tonsils Lymphatic cells Lymph Vessels Lymphatic Capillaries 24Anatomic features: 8 Blind end (closed end, not connected) Single layer of overlapping endothelial cells High permeability, more than blood capillary Present in the interstitial space of vascular structures Absent in avascular structures brain, spinal cord splenic pulp and bone marrow Lacteals 249 Special types of lymphatic capillaries in the small bowel Besides picking up interstitial fluid they take dietary lipids and lipid-soluble vitamins (ADEK) The lymph is milky color due to the lipid, AKA chyle Lymphatic Vessels 2410 Anatomic features Three layered wall - thinner than veins Valves presents – more numerous than in veins Interposed by lymph nodes at intervals Lymph Trunks Formed by confluence of many efferent lymph vessels Right and left jugular trunks Right and left subclavian trunks Right and left bronchomediastinal trunks Right and left lumbar trunks intestinal trunk Cisterna chyla - located just inferior to the aortic hiatus of the diaphragm Right and left ext. and internal iliac lymph trunk Lymphatic Ducts 2412 Right lymphatic duct Formed by union of right jugular, subclavian, and broncho-mediastinal trunks Ends by entering the right venous angle (union of the R internal jugular vein and R subclavian vein) Lymphatic Ducts Thoracic duct Begins in front of L1 as a dilated sac, the cisterna chyli, formed by left and right lumbar trunks and intestinal trunk Enter thoracic cavity & ascends Travels upward, swings to the left at the level of T5 Lymphatic Ducts Thoracic Duct….. At the root of the neck, it turns laterally before termination, it receives the left jugular, subclavian and bronchomediastinal trunk arches forwards and descends to enter the left venous angle (union of the L internal jugular vein and L subclavian vein) Drainage Pattern Right Lymphatic Duct Receives lymph from right half of head, neck, thorax and right upper limb, right lung, right side of heart, right surface of liver Thoracic Duct Drains lymph from lower limbs, pelvic cavity, abdominal cavity, left side of thorax, and left side of the head, neck and left upper limb Lymphatic Cells 2416 Also called lymphoid cells Located in both the lymphatic system and the cardiovascular system Work to elicit an immune response Types of lymphatic cells are: macrophages epithelial cells dendritic cells lymphocytes Lymphatic Organs Primary organs Bone marrow Thymus gland Secondary organs Lymph nodes Lymph nodules Spleen Lymph Nodes 2418 round Small, or oval located along the pathways of lymph vessels. length from 1 - 25 millimeters Typically found in clusters receive lymph from many body regions Also found individually throughout the body tissues Lymph Nodes Features Bean-shaped bodies With afferent vessels (entering at the periphery) and efferent lymph vessels(emerging at the hilus) Arranged in groups, along the blood vessels or the flexural side of the joint Divided into superficial and deep groups Regional Lymph Drainage Sentinel Lymph Node - is regional node(s) is the lymph Node is the lymph node where the lymph of an organ drains into first Portal of metastasis is cancer Spleen Location Left epigastric region between 9th-11th rib Largest lymphatic organ in the body Can vary considerably in size and weight White pulp is lymphatic tissue consisting mainly of lymphocytes around arteries Red pulp consists of venous sinuses filled with blood and cords of lymphatic cells, such as lymphocytes and macrophages. Function Fights invading germs in the blood Splenic sequestration -controls the level of blood cells (white blood cells, red blood cells and platelets) Filters the blood and removes any old or damaged red blood cells Thymus Features Consists of two elongated lobes Is a large organ in the fetus Occupies the thoracic cavity behind the sternum Secrete lymphopoietin AKA Thymic stromal lymphopoietin, TSLP) - is an interleukin 7-like cytokine expressed mainly by epithelial cells Activates dendritic cells to promote T helper (Th) 2 immune responses Lymphatic Nodules Oval clusters of lymphatic cells with some 24extracellular matrix 23 Not surrounded by a connective tissue capsule Filter and attack antigens In some areas of the body, many lymphatic nodules group together to form larger structures - mucosa-associated lymphatic tissue (MALT) Tonsils Mucosa of the small intestine, primarily in the ileum (Peyer patches) Appendix Walls of the bronchi Conditions Associated to the Lymphatic System Lymphangitis Inflammation of the lymph vessels Commonest cause bacteria called streptococcus pyogenes(most common). Lymph vessels appear as red streaks through the skin Filariasis Lymphedema Occurs due to accumulation of lymphatic fluid in the interstitial tissue Sometimes can be appreciated after wearing tight clothing or jewelry on affected limb Lymphadenopathy Means a disease of the lymph nodes Lymph nodes become swollen/ enlarged and may be painful to touch Lymphomas Cancers originating either from the lymphocytes in the lymph nodes or the lymphatic tissue in organs Risk factors -- HIV, HEPATITIS, EBV infections, NASH Tonsillitis Infection of the pharyngeal tonsils Tonsils are swollen Fever and pain during swallowing usually present Treatment – surgical removal of tonsils (TONSILLECTOMY) Splenomegaly Enlarged Spleen