Lymphatic System PDF

Anatomy of Lymphatic System  Lymphatic System  protects body against foreign material  assists in circulation of body fluids between cells and bloodstream  transports dietary fats  Lymphatic System  Consists of: - lymph - network of vessels - lymph nodes and nodul...

Anatomy of Lymphatic System  Lymphatic System  protects body against foreign material  assists in circulation of body fluids between cells and bloodstream  transports dietary fats  Lymphatic System  Consists of: - lymph - network of vessels - lymph nodes and nodules - tonsils - spleen - thymus gland  Lymph (lympha = clear fluid)  derived from tissue fluid  contains more white blood cells than plasma  enters node through afferent lymphatic vessels  flows through node in one direction LYMPHATIC SYSTEM Essentially a drainage system accessory to venous system larger particles that escape into tissue fluid can only be removed via lymphatic system  Lymph (cont.)  flows through sinuses in lymph node cortex and then into the medulla  exits the lymph node through efferent lymphatic vessels  must be returned to blood stream to maintain blood volume and pressure  Lymph Vessels Just like  resemble veins but have thinner walls and more valves Lymph Vessels (cont.)  no pump for lymph  Lymph is kept moving by: - constriction of vessels - skeletal muscle pump - respiratory pump  at intervals along vessels lymph flows into lymph nodes  lymphatic vessels unite to form lymph trunks  Lymph Trunks  formed by lymphatic vessels uniting  large tubes  empty their lymph into lymphatic ducts  Lymphatic Ducts  Lymph empties into two conducting ducts: - the thoracic duct (left lymphatic duct) - the right lymphatic duct Lymph from these ducts enters the blood stream via the left subclavian vein and the right subclavian vein  Thoracic Duct (left lymphatic duct)  about (38-45 cm) in length  begins as a dilation called the cisterna chyli  main collecting duct of lymphatic system  receives lymph from lower body and upper left quadrant  empties into the left subclavian vein  Right Lymphatic Duct  about (1.5 cm) in length  receives lymph from upper right quadrant  empties into the right subclavian vein  Lymph Nodes  oval or bean-shaped  masses of lymphatic tissue  aid in defense and white blood cell formation  located along length of lymphatic vessels  scattered throughout the body usually in clusters  Major Lymph Nodes  cervical  axillary  inguinal  mesenteric  Cervical  located in neck area  filter lymph from head and neck Axillary  located in armpits  filter lymph from hand, arm, breast  Inguinal  located in groin area  filter lymph from lower extremities and external genital organs Mesenteric  located in abdominal peritoneum  aid in infection control after abdominal surgery  filter lymph from abdominal cavity  Metastasis  process by which bacteria or body cells are spread from one body part to another through lymphatic or circulatory systems  cancer cells migrate to nearby nodes, eg. breast cancer to axillary nodes  Tonsils  aggregations of large lymphatic nodules  embedded in mucous membrane  located beneath epithelium of pharynx and oral cavities  protect nasal and oral cavities  Three types: - nasopharyngeal tonsils - palatine tonsils - lingual tonsils  Nasopharyngeal Tonsils  commonly called adenoids  Located: - behind nose - on roof of posterior wall of pharynx - posterior opening of nasal cavity  Palatine Tonsils  usually referred to as the “tonsils”  Location: - back of mouth - lateral walls of pharynx  most commonly removed - tonsillectomy  Lingual Tonsils  base of tongue  first line of defense from exterior  Spleen  largest lymphatic organ  located in upper left abdominal quadrant  between fundus of stomach and diaphragm  resembles a large lymph node  filters blood  capsule Structure of Spleen - covering of dense connective tissue  hilum - depression on medial surface - nerves and arteries enter spleen, veins and lymphatic vessel exit  Structure of Spleen  trabeculae (cont.) - extensions of capsule, form partitions within the spleen  Pulp  - tissue inside - divided into red and white  White Pulp  consists of lymphatic tissue  mostly lymphocytes arranged around central arteries  Red Pulp  Consists of: - venous sinuses filled with blood - cords of splenic tissue consists of red blood cells, macrophages, lymphocytes, plasma cells, and granulocytes  Functions of Spleen  phagocytosis of bacteria and worn out or damaged red blood cells and platelets  stores and releases blood in times of demand, e.g., hemorrhage  functions in immunity as a site of B cell proliferation into plasma cells  does not filter lymph because it has no afferent lymphatic vessels or lymph sinuses  Thymus Gland  two-lobed organ  located in upper part of chest along trachea  inferior to thyroid gland, posterior to sternum  largest and most active during prenatal period and infancy  after puberty it decreases in size  Thymus Gland (cont.)  composed of lymphatic tissue  subdivided into lobules  immature T cells originating in the bone marrow migrate to thymus via blood  in thymus, cells develop into mature T cells for release into circulation  thymic hormones aid in maturation of T cells  Removal of Thymus (thymectomy)  can be removed but decreased T-cell production results  possible acute susceptibility to infection  Removal of Spleen (splenectomy)  can be removed  other organs, e.g. the liver and bone marrow can compensate for it  increased susceptibility to disease may result  MALT..  Is mucosa associated lymphatic tissues.  It is infiltration of mucosa by large numbers of lymphocytes.  Ex. Peyres patches of small intestine Questions?