Feedback occurs when the feedback causes the corrective measures to be turned off.
Thermoreceptors detect a rise in blood temperature, nerve impulses are sent to the hypothalamus and then the skin. Sweating and vasodilation causes the blood to resume to normal temperature. - This is negative feedback.
Fall of blood glucose. The islets of langerhans in the pancreas produce glucagon. Glucagon causes the conversion of glycogen to glucose.
Feedback causes corrective measurements.
Hypothermia involves positive feedback, when the heat loss from the body is quicker than it can be produced.