Question

1. Which of the following is a good example of homeostasis?

		A. Your plasma calcium concentration is 4.5mM.
		B. Your plasma K+ concentration has been around 4 mM for many years.
		C. You have a temperature of 103°F/38°C.
		D. You are dehydrated because of sweating heavily in a hot day.
		2. If your plasma sodium concentration is 141 mM, which of the following mechanisms is more likely to re-establish your electrolyte homeostasis?
		A. A positive feedback loop, because they produced rapid responses capable of exerting strong all-out responses that will bring your plasma sodium back to around 10 mM.
		B. A negative feedback loop, because they are good to minimize change.
		C. A negative feedback loop that triggers thirst, so that absorbed water can dilute excessive sodium
		D. No need to worry; 141 mM Na+ in plasma is within normal range, so your homeostasis is not being compromised.

Answer 1

Question no 1

Option a is wrong as in a homeostasis mechanism the normal value of an electrolyte in our blood has to be maintained . This is wrong because blood calcium normal value is   2.2- 2.7 mmol/L and in this case it is an example with hypercalcemia with 4.5mm. So in this homeostasis mechanism is not maintained and is wrong

Option b is the correct answer as in this example the homeostasis mechanism to maintain normal range of pottasium value that is 3.6 to 5.2 millimoles per liter and in this option it is around 4mm which is in the normal range . Here the homeostasis is maintained normallly .Potassium homeostasis is maintained in our human body predominantly through the regulation of our renal excretion and the adrenal gland as well as the pancreas also specifically play a significant role in it s homeostasis . The most important one is the aldosterone that will maintain the retention and the excretion of potassium in renal tubules..

Option c is wrong as the normal body temperature is 98.6 degree F and 37 degree Celsius. So in this case the give temperature is more than normal body temperature and so homeostasis is not maintained so it is wrong.

Option d is wrong as sweating is a homeostasis mechanism to maintain normal body temperature and if it results in dehydration then it is abnormal and it is not homeostasis if dehydration occur.