Essay Questions - Essay Questions Essay 4: One of the key...

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Essay Questions Essay 4: One of the key themes of biology is that structure is based on function. Describe one system that demonstrates the relationship between structure and function. The small intestine is made up of small molecules that are taken up by cells of mucosa. Located on the mucosa are villi and on the villi are microvilli. Both of these types of villus increase the surface area of the small intestine greatly, allowing more efficient aborption of nutrients from food. Since the majority of digestion occurs within the small intestine, efficiency is absolutely necessary for a successful digestive system. These villi and microvilli are an example of structure that is based on function. The small intestine is structured this way in order to function for the digestive system. Essay 5: One of the key themes of biology is that of homeostasis. Name one factor in the body that stays relatively constant in spite of a changing environment and describe the regulatory mechanism that keeps that factor constant by negative feedback. When you’re body is dehydrated there is an excess of salt in the body. The posterior pituitary gland, an endocrine gland, secretes anti-diuretic hormone (ADH) into the bloodstream. This hormone places more water channels in the collecting tube so that the kidneys can reabsorb more water and the osmotic pressure can return to its normal state. When the osmotic pressure gets too low, the posterior pituitary gland secretes less of the anti-diuretic hormone so that there are less water channels so that more water will go to the ureter and be removed as urine. Consequently, the osmotic pressure will rise. If you’re body temperature gets to be too high or too low your brain cannot function.
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This note was uploaded on 10/28/2008 for the course BIO G 110 taught by Professor Wayne,r. during the Fall '07 term at Cornell University (Engineering School).

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Essay Questions - Essay Questions Essay 4: One of the key...

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