How would you explain the role negative and positive feedback plays in maintaining homeostasis to a newly diagnosed diabetic patient?
What will be an ideal response?
Answer: Homeostasis is the process by which our body maintains a constant internal environment and this is mainly achieved through positive and negative feedback systems. A positive feedback loop is when a signal received from a substrate will result in the production of more of the same substrate (asking the body to produce more) while negative feedback is when a signal from a substrate will ease the production of the same substrate (asking the body to regulate/stop production).
A classical example of homeostasis is how the blood sugar levels are managed in our body and disruption of homeostasis related to blood sugar levels can cause diabetes.
In our body, blood sugar levels are controlled by two hormones, insulin and glucagon. The primary function of Insulin is to decrease the concentration of glucose in the blood while that of glucagon is to increase the levels of glucose in the blood. So, usually, after you have a large meal, the glucose level in the blood rises which will signal the body to release insulin from pancreatic cells and insulin signals other cells in the body like muscle and fat cells to use glucose as fuel and insulin also help in the conversion of glucose to glycogen. So, as the sugar levels go down, so does the insulin levels and homeostasis is maintained again. Similarly, when you starve for long, the glucose/sugar levels go down in the body, the hormone glucagon is released from the pancreas, which breaks down glucagon to glucose, increasing the levels to normal and thus maintaining homeostasis.
The above examples of insulin and glucagon show negative feedback loop. When the levels of glucose start to become normal, the production of insulin/glucagon is stopped. Diabetes happens due to broken feedback loop involving the hormone insulin. Due to certain reasons, the body might not be able to produce enough insulin or the body will not respond to signals from insulin. This causes the blood sugar levels to rise beyond the normal levels. The fat/muscle cells won't be able to use the glucose as the signalling to use glucose/ convert glucose to glycogen have to come from insulin and because of this, patients with diabetes will have high sugar levels.
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