Video Transcript
Why is the pancreas referred to as
a mixed gland? The pancreas contains endocrine
cells that secrete hormones and exocrine cells that secrete enzymes. Or the pancreas contains exocrine
cells that secrete hormones and endocrine cells that secrete enzymes.
Let’s approach this question by
first defining some of the key terms that’ve been used. Endocrine glands secrete hormones
directly into the bloodstream, and exocrine glands secrete substances via ducts,
usually onto body surfaces, such as the skin or the inside of the digestive
tract. This diagram represents the human
pancreas. The pancreas contains endocrine
cells within regions called the islets of Langerhan, which are shown here in
pink. These endocrine cells in the islets
of Langerhan produce and secrete hormones, such as insulin and glucagon, releasing
them into the bloodstream. Once in the blood, these two
hormones can travel to their target cells in order to have an effect, which is to
increase or decrease blood glucose concentration to maintain it within a normal
healthy range.
Most of the pancreas is made up of
exocrine tissue, which consists of clusters called acini, which contain pancreatic
acinar cells, which we can see here in orange surrounding this green structure,
which is the pancreatic duct. The acinar cells within the acini
secrete digestive enzymes into this pancreatic duct, which then empties into the
small intestine, where these enzymes are responsible for breaking down proteins,
lipids, and carbohydrates in the food that we eat. As the pancreas has both endocrine
and exocrine functions, it is sometimes referred to as a mixed gland.
Let’s use this information to
answer the question. We know now that endocrine cells
secrete hormones and that the exocrine cells of the pancreas secrete enzymes. So this option must be the correct
answer.
