Homeostasis

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The first assignment we completed was "Introduction to Homeostasis". In this assignment, we learned about feedback mechanisms. First, is negative feedback mechanisms. First, in a negative feedback loop, you feel stimulus, for example, hunger. After that a signal is sent to your brain that tells you what you need to do, for example, eating. Eating is the response in that situation. After you complete that response your stimulus is then decreased. Almost every feedback loop in the body is negative besides one. This one is childbirth. In a positive feedback loop first comes the stimulus, then the signal, then the response, but instead of your stimulus being decreased it is increased. In thermoregulation, if your temperature is too high the hypothalamus sends out signals to cool the body. The blood vessels in the skin dilate to radiate heat and sweat glands increase sweat production. When your body temperature is too low the hypothalamus sends signals out to heat the body. Blood vessels in the skin constrict to reduce heat loss and muscles begin to shiver, generating heat.

Another important assignment we did was the research for the final project. During this research, we were assigned a certain form of homeostasis and researched it. We were assigned blood glucose levels. During this assignment we learned that homeostasis is the tendency toward a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes. When the blood glucose levels get too high, the pancreas releases insulin into the blood. Insulin helps the liver and body cells take in glucose (stored in the liver as glycogen), and this decreases blood glucose levels. When blood glucose levels get too low, glucagon is released by the pancreas which causes the breakdown of glycogen back into glucose. The well-fed state operates while food is being absorbed from the intestine. CHO and fat are oxidized to CO₂ and H₂O in peripheral tissues to drive synthetic reactions and sustain cell function. After a meal, increased plasma glucose promotes the release of insulin, and surplus fuel is converted to glycogen and fat. During the final project we created a poster board and scientific articles. These assignments included an abstract, introduction, hypothesis, our procedure, data tables, a graph, and an analysis/conclusion.

Our data shows that the mean baseline blood glucose after 90 minutes of fasting was 96 mg/dl. Blood glucose for experimental subjects rose to a mean of 121.25 mg/dl 15 minutes after drinking 4oz of orange juice and then fell back to baseline levels for most subjects after 30 minutes. Control subjects who had no significant change in blood glucose over the time period of the test. Our hypothesis was partially correct. Homeostasis did cause the blood glucose to decrease quickly after drinking juice. However, it happened quicker than we thought it would. We hypothesized that while blood glucose levels would fall by 30 minutes after drinking juice, they would not get back to baseline levels. However, the mean blood glucose 30 minutes after drinking juice was almost identical to baseline levels (96mg/dl vs 94.25mg/dl). The procedure went well overall. My 15 minute measurement was really taken at about 20 minutes which slightly changed results. We don’t believe there were any errors. Ryan’s blood glucose did not go up after drinking the juice. This is likely due to normal variation in speed of glucose metabolism in people rather than an error. In some people it can take longer than 30 minutes for blood glucose to rise after eating (6). My glucose rose slower and decreased slower .It would be interesting to conduct this experiment over a longer period of time with more testing times so that we could get data about the individual differences in the timing of glucose metabolism between subjects. It would also be interesting to perform on more subjects to make the data more reliable. In conclusion, we found that glucose homeostasis caused blood glucose to fall quickly back to baseline levels within 30 minutes after drinking orange juice. This is achieved by the pancreas releasing insulin in response to increases in blood glucose which then drives the glucose into cells and body tissues for storage.