Lymphatic System PDF

LYMPHATIC SYSTEM LYMPH What is lymph ?  Tissue fluid (interstitial fluid) that enters the lymphatic vessels.  Lymph is watery fluid that moves through your lymphatic system. . Lymph collects fluids from your tissues and returns them to your blood.  It carries nutrients and proteins to your cel...

LYMPHATIC SYSTEM LYMPH What is lymph ?  Tissue fluid (interstitial fluid) that enters the lymphatic vessels.  Lymph is watery fluid that moves through your lymphatic system. . Lymph collects fluids from your tissues and returns them to your blood.  It carries nutrients and proteins to your cells and tissues.  It also collects any harmful substances found in your cells and tissues. FORMATION AND TRANSPORT OF TISSUE FLUID LYMPHATIC SYSTEM oEssentially a drainage system accessory to venous system olarger particles that escape into tissue fluid can only be removed via lymphatic system Functions of the Lymphatic System 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: ◦transported through lacteals ◦drain into larger lymphatic vessels ◦eventually into the bloodstream. lymphocyte development,and the immune response. Components of the Lymphatic System Lymph Lymphatic Vessels ◦ Lymphatic Capillaries ◦ Lymphatic Vessels ◦ Lymphatic Trunks ◦ Lymphatic Ducts Lymphatic Organs ◦ Thymus ◦ Lymph Nodes ◦ Spleen ◦ Tonsils Lymphatic cells Lymph Vessels  Lymphatic capillaries  Lymphatic collecting vessels  Lymphatic trunks  Lymphatic ducts Lymphatic Capillaries Features of structure: Blind end Single layer of overlapping endothelial cells More permeable than that of blood capillary Absent from avascular structures, brain,spinal cord splenic pulp and bone marrow Lymphatic Capillaries – Lacteals The small intestine contains special types of lymphatic capillaries called lacteals. Lacteals pick up not only interstitial fluid,but also dietary lipids and lipid-soluble vitamins. The lymph of this area has a milky color due to the lipid and is also called chyle. Lymphatic Vessels Features of structure  Three layered wall but thinner than vein,  More numerous valves than in vein  Interposed by lymph nodes at intervals  Arranged in superficial and deep sets LYMPH TRUNKS  right and left jugular trunks  right and left subclavian trunks  right and left bronchomediastinal trunks  right and left lumbar trunks  intestinal trunk LYMPHATIC DUCTS Right lymphatic duct Formed by union of right jugular, subclavian, and bronchomediastinal trunks Ends by entering the right venous angle 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,veering to the left at the level of T5.…THORACIC DUCT At the root of the neck,it turns laterally arches forwards and descends to enter the left venous angle before termination,it receives the left jugular,Subclavian and broncho- mediastinal trunk DRAINAGE PATTERN RIGHT LYMPHATIC DUCT THORACIC DUCT -Receives lymph from right half of - Drains lymph from lower limbs, head, neck, thorax and right upper pelvic cavity, abdominal cavity, left limb, right lung, right side of heart, side of thorax, and left side of the right surface of liver head, neck and left upper limb Lymphatic Cells Also called lymphoid cells. Located in both the lymphatic system and the cardiovascular system. Work together to elicit an immune response. Types of lymphatic cells are: ◦macrophages ◦epithelial cells ◦dendritic cells ◦lymphocytes LYMPHATIC ORGANS Primary organs ◦Red bone marrow ◦Thymus gland Secondary organs ◦Lymph nodes ◦Lymph nodules ◦Spleen Lymph Nodes Small,round or oval located along the pathways of lymph vessels. length from 1 -25 millimeters Typically found in clusters receive lymph from many body regions. Lymph nodes are also found individually throughout the body tissues. Lymph node  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 Spleen  Location  Left epigastric region  between 9th-11th rib  in line of 10th rib Largest lymphatic organ in the body. Can vary considerably in size and weight Function  Stores blood.  Filters blood by removing cellular waste and getting rid of old or damaged blood cells.  Makes white blood cells and antibodies that help you fight infection.  Maintains the levels of fluid in your body.  Produces antibodies that protect you against infection. THYMUS Features  Consists of two elongated lobes  Is a large organ in the fetus  Occupies the thoracic cavity behind the sternum  Secrete lymphopoietin Lymphatic Nodules  Oval clusters of lymphatic cells with some extracellular matrix that are 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) or tonsils ◦very prominent in the mucosa of the small intestine, primarily in the ileum ◦Peyer patches ◦also present in the appendix Tonsils  clusters of lymphatic cells and extracellular matrix not completely surrounded by a connective tissue capsule.  Consist of multiple germinal centers and crypts  Several groups of tonsils form a protective ring around the pharynx. ◦pharyngeal tonsils (or adenoids) in nasopharynx ◦palatine tonsils in oral cavity ◦lingual tonsils along posterior one-third of the tongue