Blood sugar level several interacting systems, of which hormone regulation is the most important. There are two types of mutually antagonistic metabolic hormones affecting blood glucose levels: These hormones are secreted from pancreatic islets which are bundles of endocrine tissues. There are four types of pancreatic islets, alpha (A) cells, beta (B) cells, Delta (D) cells and F cells. Glucagon is secreted from alpha cells, while insulin is secreted by beta cells. Together they regulate the blood-glucose levels through negative feedback, a process where the end product of one reaction stimulates the beginning of another reaction. In blood-glucose levels, insulin lowers the concentration
Self-regulating heater Self-regulating heater A self-regulating heater is an electrical heater which strives to keep a constant temperature regardless of how the ambient conditions changes. It is the material in the heater itself that regulates the temperature. The heater requires no regulating electronics, temperature sensors, overheat protection etc. The temperature the heater will hold is decided when the material and the heater is produced. It can be fine tuned by changing the voltage to the heater. Self-regulating heaters are made from materials with strong Positive temperature coefficient (PTC) characteristics, i.e. the resistivity of the material increases rapidly with increasing temperature. Such materials