Video Transcript
Blank have many types of cells that mainly secrete hormones that regulate glucose
levels in the blood. (A) Lymphatic nodes, (B) islets of Langerhans, (C) ovaries, or (D) testes.
This question asks us to identify the structure or tissue that secretes hormones that
regulate blood glucose levels.
Controlling blood glucose levels is critical because although our cells need glucose
to make ATP through cellular respiration, too much glucose has damaging effects. The pancreas, an organ that sits behind the stomach, is referred to as a mixed
gland. This is because it has both endocrine and exocrine functions.
To ensure that the body cells have enough glucose for cellular respiration, the
pancreas secretes a hormone called glucagon when blood glucose levels fall below
normal. Glucagon stimulates the breakdown of glycogen, the storage form of glucose in the
body. This has the effect of raising the blood glucose back to a normal level. When blood glucose rises above normal, the pancreas secretes a second hormone called
insulin. Insulin signals the body cells to take up excess glucose from the blood, lowering the
blood glucose level back to normal. Both insulin and glucagon are secreted from the pancreas. But this organ is not one of the answer choices. So let’s have a closer look at our options to find the right one.
You may recognize the lymphatic nodes as exocrine glands within the immune
system. They are not involved in blood sugar regulation, so we can rule this answer out. The islets of Langerhans are areas of endocrine tissue within the pancreas. They contain several types of specialized cells that secrete hormones into the blood,
including 𝛼 and 𝛽 cells. 𝛼 cells are responsible for secreting glucagon, while 𝛽 cells secrete insulin. This looks like the best answer to our question, but let’s review answer choices (C)
and (D) to be sure.
Both the ovaries and the testes are reproductive organs. They primarily secrete sex hormones, such as estrogen and testosterone, which are
important for sexual development and reproduction. However, sex hormones do not directly regulate blood glucose levels.
Therefore, the correct answer choice is (B). And the completed sentence reads “Islets of Langerhans have many types of cells that
mainly secrete hormones that regulate glucose levels in the blood.”
