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
Blood-oxygen-level dependent imaging correlated fluctuations called resting state fMRI. Its proof of concept of blood-oxygen-level dependent contrast imaging was provided by Seiji Ogawa and Colleagues in 1990, following an experiment which demonstrated that an "in vivo" change of blood oxygenation could be detected with MRI.In Ogawa's experiments,blood-oxygen-level dependent imaging of rodent brain slice contrast in different components of the air. At high magnetic fields, water proton magnetic resonance images of brains of live mice and rats under anesthetization have been measured by a gradient echo pulse sequence. Experiments shown that when the content of oxygen in the breathing gas changed gradually, the contrast