RQ-1A Predator is a long-endurance, medium-altitude unmanned aircraft system for surveillance and reconnaissance missions. Predator UAVs have been operational in Bosnia since 1995, where they have flown more than 600 missions for more than 4,000h in support of Nato, UN and US operations. Predator operated from a tactical control station located aboard the USS Carl Vinson, Nimitz class aircraft carrier.
Secretin functions as a type of fireman: it is released in response to acid in the small intestine, and stimulates the pancreas and bile ducts to release a flood of bicarbonate base, which neutralizes the acid. Secretin is also of some historical interest, as it was the first hormone to be discovered. similar, but quantitatively less important response to secretin is elicited by bile duct cells, resulting in additional bicarbonate being dumped into the small gut. As acid is neutralized by bicarbonate, the intestinal pH rises toward neutrality, and secretion of secretin is turned off.
The pancreas lies beneath the stomach and is connected to the small intestine at the duodenum (see digestive system). The pancreas contains enzyme producing cells that secrete two hormones. The two hormones are insulin and glucagon. Insulin and glucagon are secreted directly into the bloodstream, and together, they regulate the level of glucose in the blood.