HLSC 1201U Lecture Notes - Lecture 6: Mediastinum, Thymus, Thymosin
Document Summary
Lymphatic system is closely related to digestive & cardiovascular systems. Clear, watery-appearing fluid similar to plasma but proteins = isotonic. Lymphatic system is a one way system not continuous (cardiovascular) Functions fluid circulation, immunity (lymph nodes contain wbcs) drain excess interstitial fluid, transport dietary lipids. Lymphatic capillaries larger lymph vessels + nodes lymph nodes. Breathing movements and skeletal muscle contractions establish a fluid pressure gradient: can be sped up through exercise, as with venous blood. Other factors such as if pressure, also drive lymphokinesis. Similar to veins except lymphatic vessels have: thinner walls, more one-way valves, lymph nodes, anchoring fibers. Edema (swelling) opens up gaps between cells even further to let lymph in. As lymphatic vessels diameter increases thicker walls with three layers. Valves are present at least every few millimeters. Nodes are a type of biological filter. Once lymph enters a node, it moves slowly through sinuses to drain into the efferent exit vessel.
