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Worksheet 14 Veins and Lymphatic SystemName some structural differences between veins and arteries.Veins are larger in diameter and have less smooth muscle in their walls. They also hold more blood at any given time than arteries. Because of the lower amount of smooth muscle in tunica media, veins collapse when emptyWhat are valves? What is the function of valves? Do all blood vessels have valves?Valves in veins are extensions of the tunica intima (innermost layer of the wall). Since blood in venous vessels has to fight against gravity, the presence of these valves in veins helps prevent backflow of blood. Not all blood vessels have valves. Arteries don’t have them but MOST veins do. The only veins that do not have valves are the ones found near digestive organs and the major veins like the superior and inferior vena cava. If the valves become faulty and blood starts pooling near them, a condition called varicose veins occurs**Muscle contractions are very important to create a pump that pushes blood against gravity**Which veins are responsible for draining the thoracic wall? What is the submucosal esophageal plexus? Esophageal plexus?Azygous vein (on the right side) and hemiazygous vein (on the left side) both drain into the superior vena cava. The submucosal esophageal plexus is what drains the esophagus.Veins of the head and neck drain blood into what veins before reaching the superior vena cava?They dump blood into subclavian vein and then into the brachiocephalic vein and then into the superior vena cavaWhat is the importance of the internal jugular vein?The internal jugular veins are important in returning fluid from the ventricular system of the brain back into circulation. CSF (and deoxygenated blood) from ALL dural venous sinuses drain into the internal jugular veinDraw a diagram showing the major tributaries of the Inferior vena cava and the organs they drain. See flow sheets***Occlusion of the LEFT renal vein may cause varicosity in the LEFT testicular artery which can be easily seen**What is deep vein thrombosis? Which are is in particular danger of this condition?Deep vein thrombosis is a condition in which a large clot appears in a deep vein usually of the leg. This is dangerous because if the clot becomes too large, bits of it may break off and travel along the blood vessels as an embolism. If it reaches the pulmonary blood vessels, it is deadly. This condition is referred to as pulmonary embolism. Areas in particular danger of deep vein thrombosis are the legs and specifically the back of the knee (popliteal fossa)What is the respiratory organ of the fetus?placentaDescribe the 2 possible ways flow of blood happens in a fetusPlacentaumbilical veinsliverductus venosusinferior vena cavaR atriumforamen ovaleL atriumL ventricleaortasystemic circulationumbilical arteriesback to placentaPlacentaumbilical veinsliverductus venosusinferior vena cava R atrium R ventriclepulmonary trunkductus arteriosusaortasystemic circulationumbilical arteriesback to placenta**notice how one completely bypasses pulmonary circuit and goes right into the systemic circuit through the foramen ovale****notice how the other one passes through the pulmonary circuit but then instead of going to the lungs and continuing the systemic circuit, it just goes straight into the aorta and into systemic circulation**What are the 2 fetal remnants in the adult heart? What were they in the fetal heart?Foramen ovale in between R and L atria becomes fossa ovalis in the adultDuctus arteriosus in between the pulmonary trunk and aortic arch becomes ligamentum arteriosum in adult**these fetal structures MUST close at birth. If they don’t, mixing of deoxygenated and oxygenated blood can happen and can lead to many problems.**LYMPHATIC SYSTEMWhat are the components of the lymphatic system?Lymph nodes, lymph vessels (capillaries), lymphatic organs, and lymphWhere are lymph nodes mostly located?Areas that are open to the outside (nose, mouth, genitals) and also a long glands (salivary glands, mammary glands, etc) and digestive organs!What is lymph?Ultrafiltrate of blood. It is a fluid usually made up of lymphocytes and also interstitial fluid. Comparable to blood plasmaIt looks different depending on where it is coming from. If it coming from the intestines it is called CHYLE and it is high in fat and appears white.If it is coming from the liver it is high in protein and yellowish!How are lymphatic capillaries alike or different than vascular capillaries?Lymphatic capillaries are irregularly shaped, have unfused linings that allow them to overlap, and also have valves. **Since the edges of endothelial cells of lymph vessels overlap, a one-way direction of flow is created. That is, interstitial fluid flows in and cannot flow out.**What is the cysterna chyli?Sac at the lower end of the thoracic duct at which chyle (lymph from the gut) and lymph from the other lower nodes of the body is dumped intoWhat is the difference between the thoracic duct and the right lymphatic duct?Most lymph of the body drains into the thoracic duct. Only the upper right quadrant is dumped into the the right lymphatic ductWhy is drainage to the axillary lymph nodes important?Most lymph from the mammary glands drains into the axillary lymph nodes. If any cancerous cell is coming from the breast, it usually would get caught there at the axillary nodes. Thus, axillary nodes are important check points for breast cancer because if a cancer cell would get caught there, the node would start swelling because of the multiplication of lymphocytes and it could be easily palpated in a mammogram. ................
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