The Lymphatic System Latest Revision Questions and Verified Correct Answers

Lymphatic system - returns fluids that have leaked from the vascular system back into the blood Lymphoid organs and tissues - Provide the structural basis of the immune system. Play essential roles in the body's defense mechanisms and its resistance to disease. Spleen, thymus, tonsils, other lymphoid tissues, lymph nodes. Lymphatic vessels or Lymphatics - Elaborate networks of drainage vessels that collect the excess protein-containing interstitial fluid and return it to the bloodstream. Lymph - Once interstitial fluid enters the lymphatic vessels Lymphatic capillaries - The transport of lymph begins in microscopic blind-ended LYMPHATIC CAPILLARIES. They weave between the tissue cells and blood capillaries in the loose connective tissues of the body. Widespread but absent from bones and teeth, bone marrow, and the entire central nervous system. Structural modifications of lymphatic capillaries - 1. The endothelial cells forming the walls of lymphatic capillaries are not tightly joined. The edges of adjacent cells overlap each other loosely, forming easily opened, flaplike MINIVALVES. 2. Collagen filaments anchor endothelial cells to surrounding structures so that any increase in interstitial fluid volume opens the minivalves, rather than causing the lymphatic capillaries to collapse. When fluid pressure in the interstitial space is greater than the pressure in the lymphatic capillary - the minivalve flaps gage open, allowing fluid to enter the lymphatic capillary. When the pressure is greater inside the lymphatic capillary - it forces the endothelial minivalve flaps shut, preventing lymph from leaking back out as the pressure moves it along the vessel. Lacteals - Transports absorbed fat from the small intestine to the bloodstream. Milky white lymph that drains through them. CHYLE drains from the fingerlike villi of the intestinal mucosa. Collecting lymphatic vessels - have the same three tunics as veins, but the collecting vessels have thinner walls and more internal valves, and they anastomose more. Lymphatics in the skin travel - along with superficial veins The deep lymphatic vessels of the trunk and digestive viscera travel - with the deep arteries Lymphatic trunks - The largest collecting vessels unite to form LYMPHATIC TRUNKS, which drain fairly large areas of the body