Video Transcript
Which of the following structures
are mainly involved in the exocrine function of the pancreas? (A) The islets of Langerhans and
pancreatic medulla, (B) the pancreatic acini and beta cells, (C) the pancreatic
medulla and nephrons, or (D) the pancreatic acini and duct.
This question asks us about the
pancreas, which is a very important organ in the human body with both endocrine and
exocrine functions and, as a result, is often referred to as a mixed gland.
The pancreatic endocrine cells are
found in regions called the islets of Langerhans. These cells, for example, 𝛼 cells
and 𝛽 cells, are responsible for secreting many different hormones directly into
the bloodstream. However, we are looking for the
structures in the pancreas that have an exocrine function. As a result, we can eliminate both
options (A) and (B) from our answer choices, as they are describing at least one
structure involved in pancreatic endocrine function, not exocrine function.
Exocrine glands are responsible for
producing and secreting substances via a duct onto a body surface. Most of the pancreas is made up of
exocrine tissue, which contains pancreatic acini. Pancreatic acini are clusters of
pancreatic acinar cells that are responsible for producing a fluid called pancreatic
juice. Pancreatic juice contains several
different digestive enzymes and an alkaline substance called sodium bicarbonate. Pancreatic juice is secreted via
the pancreatic duct onto the inner surface of the upper part of the small intestine,
which is called the duodenum.
The digestive enzymes in pancreatic
juice, such as lipase, help to break down large molecules in food like lipids into
smaller molecules that are easier to absorb across the wall of the small
intestine. The alkalinity provided by sodium
bicarbonate helps to neutralize the acid arriving from the stomach, which food
passes through just before the duodenum as it moves through the digestive tract,
providing the optimum pH for these enzymes acting in the small intestine.
Having reviewed the exocrine
function of the pancreas, we have found the correct answer to this question. The structures that are mainly
involved in the exocrine function of the pancreas are listed in answer choice (D),
the pancreatic acini and duct.
