This allows the blood to gather as much oxygen as it can hold Since water must

This allows the blood to gather as much oxygen as it

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countercurrent pathway, the blood is always passing water that still has oxygen. This allows the blood to gather as much oxygen as it can hold. Since water must be flowing over the gills to provide a continual source of oxygen, fish have developed several ways to keep them ventilated. Some fish swim with their mouths open almost all of the time. Other fish have a special flap called an operculum, which is used to force water across the gills. c.) Mammals Mammalian respiratory systems rely on a single large muscle at the base of the lungs. This muscle is called a diaphragm. The diaphragm pulls the lungs downward to increase their volume, causing air
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to rush into the lungs. As it presses upward, the lungs become smaller, and air is exhaled. Muscles in the rib cage work in consort with the diaphragm to expand and contract the lungs. Different mammals breathe differently. Some breathe through the nose, others breathe through the mouth. Some mammals are able to breathe through either the nose or the mouth. As the air passes through the nose or down the trachea, or airway, small hairs and microscopic hair-like structures filter the air by attracting dust and microbes that could cause damage or infection in the lungs. As the air passes through the airways, it enters the lungs. Mammals have two lungs. The air is split between the lungs by an airway called bronchi. It moves to smaller airways called bronchioles. The bronchioles take the air to alveoli, which are small sacks where the gas transfer occurs. In addition, large animals cannot maintain gas exchange by diffusion across their outer surface. As a result, they developed a variety of respiratory surfaces that all increase the surface area for exchange, thus allowing for larger bodies. A respiratory surface is covered with thin, moist epithelial cells that allow oxygen and carbon dioxide to exchange. Those gases can only cross cell membranes when they are dissolved in water or an aqueous solution, thus respiratory surfaces must be moist. 3.) Atherosclerosis, the cause of myocardial infarction, stroke, and ischemic gangrene, is an inflammatory disease. The atherosclerotic process is initiated when cholesterol-containing low- density lipoproteins accumulate in the intima and activate the endothelium. Leukocyte adhesion molecules and chemokines promote recruitment of monocytes and T cells.
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  • Fall '17
  • Randy Smith
  • inflammatory disease

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