Anatomy and Physiology Answer Key

B veins have a larger lumen than arteries 2 most of

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Unformatted text preview: lastic and muscle tissue to enable the veins to adjust to changes in blood volume and pressure. The symptoms of Type 1 diabetes mellitus include high blood sugar and excretion of glucose in the urine, increased urine production, accelerated fat breakdown and ketosis, excessive thirst and hunger, and weight loss. These symptoms arise as a result of the lack of insulin, which is required in order for cells to take up glucose. The cells are deprived of glucose, hence the excessive hunger and loss of weight, but blood glucose is too high, hence excessive excretion of glucose, excessive urination, and excessive thirst. 3. Veins are "massaged" by the skeletal muscles (e.g. leg muscles). Valves (together with these muscular movements) help to return venous blood to the heart by preventing backflow away from the heart. Extra note: When skeletal muscles contract and tighten around a vein the valves open and blood is driven towards the heart. When the muscles relax, the valves close, preventing backflow. 4. Venous blood oozes out in an even flow from a wound because it has lost a lot of pressure after passing through the narrow capillary vessels (with their high resistance to flow). Arterial blood spurts out rapidly because it is being pumped directly from the heart and has not yet entered the capillary networks. (a) Insulin injection (of human insulin produced from industrial culture of genetically modified microbes). (b) Cell therapy: Transplant of insulin producing cells. (c) Gene therapy: Insertion of the gene for insulin production into the cells of diabetics. Capillaries and Tissue Fluid (page 109) 1. Capillaries are very small blood vessels forming networks that penetrate all parts of the body. The only tissue present is an endothelium of squamous epithelial cells. In contrast, arteries have a thin endothelium, a central layer of elastic tissue and smooth muscle and a thick outer layer of elastic and connective tissue. Veins have a thin endothelium, a central layer of...
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