Source: Images from Adobe Illustrator; Public Domain
Welcome to this lesson today on organs of the endocrine system. Today we are just going to be giving a brief overview of the various organs and the hormones that they secrete that are all associated with the endocrine system.
So we are actually going to start by labeling the hypothalamus. And the hypothalamus is in a region of the brain right up here. So the hypothalamus, basically its role is that it secretes hormones such as ADH and oxytocin. So ADH is also known as the antidiuretic hormone. And oxytocin is a hormone that plays a role in childbirth, among other aspects as well.
And so a gland that we have that's very closely associated with the hypothalamus is the pituitary gland. So the pituitary gland is a gland that works very closely with the hypothalamus. So the pituitary gland, basically it stores and releases hormones that were produced in the hypothalamus.
So the hypothalamus will produce some hormones. And then those hormones will be stored and released by the pituitary gland. And in addition to that, the pituitary gland also makes and secretes some of its own hormones, such as growth hormone, luteinizing hormone, and follicle stimulating hormone, for example.
So another part of the endocrine system that we're going to label is the pineal gland. So the pineal gland is a gland that secretes melatonin. And basically melatonin is a hormone that plays a role in our sleep and wake cycles. So that's what the pineal gland is responsible for.
So moving on from there, we have our thyroid gland, which is located in the neck. And our thyroid gland has a couple of different roles. It releases thyroid hormone, abbreviated TH, which plays a role in metabolism. And it also releases calcitonin. And calcitonin is a hormone that plays a role in bone remodeling. So those are kind of the two main hormones released by the thyroid gland.
And then the parathyroid, actually found on the thyroid gland, also plays a role in bone remodeling. So there are actually four parathyroid glands. And they release parathyroid hormone, or PTH. So as I mentioned, that also plays a role in bone remodeling.
So moving on from there, we have our thymus gland. And the thymus gland releases thymosins. And so the thymus gland is also where T-cells, which are a part of our immune system, they're a type of white blood cell, that's where these T-cells are actually stored and allowed to mature. So it does play a role in those T-cells being stored and matured, which plays a role in our immune system.
Moving on from there, we have the pancreas. So the role of the pancreas then is to make and secrete insulin and glucagon. So insulin is a hormone that lowers blood sugar levels. And glucagon is a hormone that raises blood sugar levels. So somebody who is diabetic, for example, their body doesn't create or secrete the hormone insulin. So they have take insulin injections in order to make up for that to help lower blood sugar levels in their body.
The adrenal glands, we have two of them, one here and one here, found on top of the kidneys are the next organ of the endocrine system we're going to talk about. So these adrenal glands, basically what they do is they secrete the hormones epinephrine and norepinephrine, which create kind of that fight or flight response that prepare the body for different types of situations. If you're in a dangerous situation, you get that rush of adrenaline. That's coming from those adrenal glands. It also really says out cortisol and aldosterone.
So if we move on to male- and female-specific organs of the endocrine system, for the females we have the ovaries. So the ovaries basically release progesterone and estrogen. Those are its two main hormones, again, that are female-specific. And male-specific, we have the testes, which make and secrete testosterone. So testosterone is a male-specific hormone.
So this lesson has been an overview on the various organs of the endocrine system, as well as the different hormones that those organs create and secrete.
Located on top of the kidneys, the adrenal glands have two anatomic divisions: the renal cortex and the renal medulla. The renal cortex secretes hormones that regulate body mineral levels, metabolism, and aid in the production of sex hormones. The adrenal medulla releases hormones called catecholamines (adrenaline) that elevate our metabolism in response to stress.
An area of the cerebrum that is located below the thalamus that controls that activity of the pituitary gland.
The primary sex organs of females and are their primary source of estrogen and progesterone; the ovaries are also where the female gamete (ova/eggs) are matured and released from.
A mixed gland (both endocrine and exocrine); the endocrine functions of the pancreas are to secrete insulin and glucagon to regulate blood glucose levels.
A group of glands on the posterior thyroid that secrete parathyroid hormone to increase blood calcium levels by decreasing renal excretion of calcium and increasing osteoclast activity.
A gland located in the cerebrum that secretes melatonin, an important hormone for regulating sleep/wake cycles.
Called the “master gland” because of its effects on other glands; endocrine hormones increase activity/secretion of many major glands of the endocrine system.
The primary sex organs of males and are their primary source of testosterone; the testes are also where the male gamete (sperm) is produced and matured.
A gland located in the mediastinum above the heart that secretes thymosins that regulate immune activity.
The largest endocrine gland located on the anterior trachea, the thyroid gland secretes hormones that elevate basal metabolic rate (BMR) called T₃ and T₄. The thyroid gland also secretes a hormone called calcitonin that lowers blood calcium levels by increasing renal excretion of calcium and inhibiting osteoclasts.