1. Everyone around you in class last week was sneezing and coughing. You woke up this morning feeling ill. You especially notice that you feel very cold. You cover up and drink warm tea but you are still so cold that you are shivering. Why do you feel this way?
Exposure to the cold virus has infected you and caused your body temperature to drop
2. You meet someone at a party and are amazed at how obese the person is. It is obvious that your new acquaintance is very uncomfortable about their appearance and he offers an explanation for being overweight. He claims that he suffered a head injury as a child and hasn't been able to control his eating since that time. He says he always feels hungry. What is your opinion?
He could have suffered damage to his satiety center in the hypothalamus
He probably received a blow that damaged his feeding center
Sorry, this is incorrect. The physiological response to an infection is not a reduction in body temperature. An increase in body temperature is actually one of the mechanisms that allow the body to fight the infection.
This is correct. When the body is invaded by the virus there is an interaction with cells within the body that results in the release of pyrogens. These substances are carried in the circulation to the hypothalamus where they act on the temperature regulatory neurons. The result of this action is a resetting of the temperature set point (the "thermostat") to a higher level. With a higher set point your body responds as it would to exposure to a cold environment and activates mechanisms that lead to an increase in body temperature (e.g., shivering). Shivering and the feeling of cold diminishes and disappears when the new temperature set point if obtained. Although a fever can be uncomfortable and, perhaps, dangerous the elevation in temperature is a beneficial response of the body to combat the infection.
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Sorry, this answer in not correct. The feeding center in the hypothalamus is important in regulating food intake. However, the feeding center is thought to be tonically active and, if left unchecked, would result in the excessive intake of food. This would occur even if you have just consumed food. Normal function results in transient inhibition of the feeding center and, thus, the termination of eating. Damage to the feeding center would result in aphagia (diminished or absence of eating) and a loss in body weight.
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Correct. The hypothalamus is an important site in the central nervous system that controls food intake. Within the hypothalamus there are two areas that interact to regulate food intake. One theory states that there are specialized glucose "sensors", sometime referred to as glucostats or glucose receptors. These receptors respond to the level of glucose utilization. It is thought that these receptors reside in the portion of the hypothalamus considered to be the "satiety" center (ventromedial nucleus of the hypthalamus). When glucose utilization is high (as in after a meal) the glucostats become activated and, thus, activate the "satiety" center. The satiety center, in turn, inhibits the tonically active feeding center. There is also evidence supporting a role for specific sensors for lipids and amino acids as well.
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