Lymphatic-System - Lymhatic System Today’s topics What is...

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Unformatted text preview: Lymhatic System Today’s topics What is the lymphatic system What Composition of lymph Composition Formation of lymph Formation Transportation of lymph Transportation The transportation system The What are lymph nodes What Lymphatic System The lymphatic system consists of a unique set of vessels separate from the circulatory system that includes a clear lymph. These vessels lack a pump such as a heart and must depend on other means to transport the fluid. Compositon of lymph (cont) Thus fluid, called interstitial fluid, is simply Thus interstitial blood plasma minus most of the proteins. When blood enters the arteriole end of a When capillary, it is still under pressure produced by the contraction of the left ventricle. As a result of this pressure, a substantial amount of water and some plasma proteins filter through the walls of the capillaries into the interstitial space. Composition of Lymph The lymph is clear although it has many The components of blood it lacks erythroctyes (RBC’s) and thrombocytes (platelets). RBC’s) Naturally the red blood cells would cause Naturally the lymph to be red similar to blood not clear. Formation of lymph The lymph forms when the interstitial fluid The escapes from spaces and enters a lymph capillary. The fluid in the interstitial spaces is known The as interstitial fluid. When this fluid enters a lymph vessel it is When then called lymph. It has the same elements as interstitial fluid It the location is the reason for the name change. 1 Lymph vessels Lymph capillary working The smallest of the lymph vessels would The be the lymph capillaries. These vessels have one way valves that These allow the interstitial fluid to enter the lymph capillaries but not escape. 1-way valve Lymphatic System Following the lymph The lymph moves from the lymph The capillary to larger lymph vessels. The lymph vessels have enlarged The swollen-like structures on them called swollenlymph nodes. Lymph nodes Several hundred lymph nodes are Several scattered throughout the lymphatic system, especially in the groin groin armpits armpits abdomen and abdomen neck. neck. Function of lymph nodes These contain cavities - called sinuses These sinuses into which the lymph flows. The walls of the sinuses are lined with phagocytic cells, which engulf any foreign particles, e.g., bacteria, that might be present in the lymph. Tests have demonstrated that over 99% of the bacteria carried into a node are screened out before the lymph leaves the node on its return to the blood. 2 Lymph node from a cat Lymph node (details) Size of a large pea Location of lymph nodes Lower lymph nodes Lymph vessels go here Thoracic duct All of the lymph vessels dump into one of two All subclavian veins. All the lymph collected from the entire All left side of the body, left the digestive tract and the the right side of the lower part of the body the flows into a single major vessel, the thoracic thoracic duct ( also known as left lymphatic duct) 3 One third of lymph goes to the right lymphatic duct. The right upper quadrant dumps into the The right lymphatic duct. Thus all the lymph is returned to the Thus blood. The lymph originated from the blood and The returned to the blood. IF no heart why does it move. Lymph vessels surrounded by Lymph smooth muscle which contracts myogenically & propels lymph forward Lymph vessels lie between skeletal Lymph muscles; lymph is also propelled forward by skeletal muscle contraction Lymph flow continued By breathing the thorax creates a vacuum that draws the lymph toward the thoracic cavity where the thoracic duct is found. The production of new lymph also propels the lymph away from the interstitial spaces and into lymph capillaries. Other interesting websites Pohala’s Home website This presentation can be viewed as a This slide show or printed out in a handout version by going to the website and clicking on links and choosing lymphatic system and choosing whether to view as a slide show or print out. More websites mphatic/ BiologyPages/L/Lymphatic.html http://www.cayuga ymphatic2/lymphatic2.html 4 ...
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