Full Stomach, Gallbladder and Pancreas (Cross-section View) Description
[Continued from above] . . . interior of the stomach. With some diseases, gastric folds become enlarged. The stomach is also a storage compartment. This enables us to eat only two or three meals a day. If this weren't possible, we would have to eat about every twenty minutes to take in adequate calories for survival. The average adult stomach stretches to hold from two to three pints, and produces approximately the same amount of gastric juices every twenty-four hours. The stomach has several functions. It acts as a storage bin, holding a meal in the upper portion and releasing it a little at a time into the lower portion for processing. It also acts as a food mixer since the strong muscles contract and mash the food into a sticky, slushy mass. It is a sterilizing system, where the cells in the stomach produce an acid, which kills germs that are naturally found in many foods. And, lastly, it acts as a digestive tub-the stomach produces digestive fluid that splits and cracks the chemicals in food to be distributed as fuel for the body. The process of digestion is triggered by the sight, smell, or taste of food, so that the stomach is prepared when the food arrives.
The gallbladder is an active storage shed, which absorbs mineral salts and water received from the liver and converts it into a thick, mucus substance called bile, which is released when food is present in the stomach. The gallbladder is a small, pear-shaped sac that is situated just below the liver and is attached to it by tissues. It stores bile and then releases it when food passes from the stomach to the duodenum to help in the process of digestion. It has a capacity of around one and one-half fluid ounce. When food leaves the stomach, a secretion causes the gallbladder to contract and expel its contents into the duodenum, where the bile disperses the fats in the food into liquid.
The pancreas is a long, tapered gland that lies across and behind the stomach. The head of the pancreas (the right-hand end which is the broadest part of the organ) lies within the curve of the duodenum. This gland secretes digestive juices that break down fats, carbohydrates, proteins and acids; it also secretes bicarbonate, which neutralizes stomach acid as it enters the duodenum. Some cells in the pancreas secrete hormones that regulate the level of glucose in the blood. Most of the pancreas consists of tissues that are embedded in nested cells. These cells secrete the digestive enzymes into tubes that meet to form the main duct. This duct joins the cystic duct (which carries bile from the gallbladder) and forms a small chamber that opens into the duodenum. The cells of the pancreas are surrounded by many blood vessels; the pancreas uses these vessels to secrete hormones (glucagon and insulin) into the blood. Insulin regulates the use of glucose into all the body tissues except the brain. If the pancreas fails to produce insulin or secretes it in low quantities, the result is a serious disease called diabetes mellitus. Inside, the organ's appearance resembles a stalk with clusters of grapes attached to it. The stalk is a long duct that runs down the center of the pancreas and the grapes are clusters of cells that flow into this duct and later into the duodenum for digestion of proteins, fats and carbohydrates.
If the ducts leading from the pancreas are blocked in some way, the digestive fluids build up in the pancreas and may then become activated so that they digest the pancreas itself! This condition is known as acute pancreatitis. Pancreatic cancer has the worst prognosis of any of the types of cancer. This is probably because of the spongy, vascular nature of this organ and its vital endocrine and exocrine functions. Pancreatic surgery is a problem because the soft, spongy tissue that it consists of is very blood-rich, but its texture makes it extremely difficult to suture.