2 What is the lymphatic system? An extensive drainage network that helps keep bodily fluid levels in balance and defends the body against infections.Together with lymphoid organs and tissues, provide the structural basis of the immune system
3 Lymphatic characteristics One way system to the heartCarries clean fluids back to the bloodDrains excess fluid from tissuesLymph is a clear, watery fluid that contains protein molecules, salts, glucose, urea, and other substances — throughout the body.Removes antigens from the body and exposes antigens to the immune systemLymph may contain macrophages, viruses, bacteria, cellular debris and even traveling cancer cells.Exercise. Exercise helps to restore flexibility and strength, and improves drainage. Specific exercises will be recommended by your doctor and/or physical therapist.Bandage. Wearing a customized compression sleeve or elastic bandage may help to prevent an accumulation of fluid.Arm pump. Applying an arm pump often helps to increase the fluid flow in the lymphatic vessels and keeps the fluid from collecting in the arm.Diet. Eating a well-balanced diet and controlling body weight is an important part of treatment.Keep the arm raised. Keeping the arm raised above the level of the heart, whenever possible, allows gravity to help drain the accumulated fluid.Prevent infection. It is important to follow preventive measures, such as good skin care, to protect the affected arm from infection and skin breakdown.
4 What type of vessels make up the lymphatic system? Vessels are called lymphaticsThin walled and analogous to veins2 large ductsRight lymphatic ductThoracic ductBoth empty into the right and left subclavian veinsDrained by the right lymphatic ductDrained by thoracic duct
6 Lymph nodes Principal lymphoid organs of the body Most are bean shaped organs along lymphatic collecting vesselsUp to 1 inch in sizeGrouped together at various parts of the bodyClusters of both superficial LNs deep
7 Lymph nodes Superficial Deep Cervical Axillary Inguinal TracheobronchialAorticIliac
8 Circulation in the lymph nodes Enters via afferent lymphatic vesselsTravels through large subcapsular sinus and smaller sinusesExits the node at the hilus via efferent vesselsAfferent vesselsEfferent vessels
9 Critical Thinking Question Why are there more afferent lymphatic vessels carrying lymph to the lymph nodes than there are efferent lymphatic vessels?Answer:Fewer efferent vessels, causing flow of lymph to stagnate, allowing lymphocytes and macrophages time to carry out functions
10 What function do lymph nodes have? Filter lymphmacrophages destroy microorganisms and debrisImmune system—lymphocytes are activated and mount an attack against antigens
12 Spleen Largest lymphoid organ Filters blood (lymph nodes filter lymph) Filters blood of bacteria, viruses, and other debris (blood-borne antigens “white pulp”Removes and destroys worn out red blood cells (RBCs)Stores plateletsSite of lymphocyte production and immune surveillance and responseIn fetus only: RBC are made in the spleenSusceptible to injury; splenectomy increases risk of bacterial infectionsome of the breakdown products of RBCs to the liver ..for example Fe, so that more RBCs can be made .The unusable portion of worn-out blood is excreted in bile.Platelets- Platelets are not cellscytoplasmic fragments of very large cells called megakaryocytesFunction in the process of hemostasis or stoppage of bleedingPlatelets have granules containing chemicals that act in the clotting process
14 Thymus Differs from other lymphoid organs in important ways It functions strictly in T lymphocyte maturationT cells become ImmunocompetentIt does not directly fight antigensSize with ageIn infants, it is found in the inferior neck and extends into the mediastinum, where it partially overlies the heartIncreases in size and is most active during childhoodStops growing during adolescence and then gradually atrophies
15 Critical Thinking Question Why does the thymus increases in size and is MOST active during childhood, stops growing during adolescence and then starts getting smaller?Answer:The thymus produces a large amount of T cells so by the time a person reaches puberty, the body has a lot of lymphocytes. The thymus also produces a variety of hormones and plays an important role in the development of immunologic competence in fetus and child.
16 Tonsils Simplest lymphoid organs Form a ring of lymphatic tissue around the pharynxCrypts trap and destroy bacteria and particulate matter
17 Mucosa-associated lymphoid tissue (MALT) Mucosal surfaces within the body are protected by the mucosal immune system consisting of the mucosa-associated lymphoid tissue or MALTAn extensive diffuse system of small concentrations of lymphoid tissue found in various sites of the body such as the gastrointestinal tract, thyroid, breast, lung, salivary glands, eye, and skin to protect from foreign matter.
18 MALTExamples:GALT (gut-associated lymphoid tissue, such as the Peyer's patches in the lining of the small intestines, as well as the adenoids, tonsils, and appendix)BALT (bronchial-associated lymphoid tissue in the bronchi)