Med-Surg Endocrine System, part 3: Cortisol, T3/T4, GH, Estrogen, Progesterone, Testosterone, Oxytocin & Prolactin

by Cathy Parkes 1 Comment

In this video, Cathy gives an Anatomy & Physiology review of some more important Endocrine hormones: Cortisol, T3/T4, Growth Hormone, Estrogen, Progesterone, Testosterone, Oxytocin and Prolactin. Nursing students should know what these hormones do, and what controls their release, in order to understand the related endocrine disorders on Med-Surg exams.

Cortisol

What is cortisol?

Cortisol is a glucocorticoid known as "the stress hormone" in the body. In addition to the body's response to stress, this hormone also helps regulate the metabolism and immune response. However, elevated levels of cortisol levels typically result from chronic (long-term) stress, rather than acute stress.

What controls the release of cortisol?

The hypothalamus will first produce corticotrophin-releasing hormone (CRH). This causes the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland, which causes the release of cortisol from the adrenal cortex.

Cortisol-related dysfunctions

Chronic stress and a high amount of cortisol can lead to detrimental effects on the body. This includes decreased immune function, increased blood pressure, and high levels of glucose in the bloodstream.

When it comes to dysfunctions and disorders, too little cortisol can cause Addison's disease, and too much cortisol can cause Cushing's disease. These disorders are covered in videos 11 and 12 of this series.

T3 & T4

What are T3 and T4?

Triiodothyronine (T3) and thyroxine (T4) are thyroid hormones that control metabolism, growth and development, heart function, brain function, muscle function, digestion, and bone maintenance. T3 is the active form of T4.

What controls the release of T3 and T4?

Like cortisol, T3 and T4 start in the hypothalamus. The hypothalamus first produces thyrotropin-releasing hormone (TRH). This causes the anterior pituitary gland to produce thyroid-stimulating hormone (TSH), which allows for production of T3 and T4 in the thyroid gland.

T3- and T4 disorders

Too much T3/T4 can lead to hyperthyroidism, and too little can lead to hypothyroidism. These disorders, including related disorders like Grave's disease, are covered in videos 14 and 15 of this series on the endocrine system.

Growth Hormone

What is Growth Hormone?

Growth Hormone (GH) controls growth, which is pretty easy to remember. In addition to growth, GH controls the body's metabolism and protein synthesis. Growth Hormone is also known as Somatotropin or human growth hormone (hGH).

What controls the release of Growth Hormone?

Again, it starts in the hypothalamus. The hypothalamus will produce growth hormone-releasing hormone (GHRH), which causes GH to be produced in the anterior pituitary gland. So far, the anterior pituitary gland is doing a lot.

Growth hormone disorders

Too much growth hormone can lead to growth hormone excess, which can lead to Gigantism or Acromegaly depending on the onset. Too little growth hormone can lead to growth hormone deficiency, which can lead to short stature. Both of these disorders are covered in video 9 of this series on the endocrine system.

Estrogen

What is estrogen?

Estrogen is a hormone that stimulates development of female sex organs and regulates the menstrual cycle.

What controls the release of estrogen?

Again, it starts in the hypothalamus. For estrogen to be released, the hypothalamus first produces gonadotropin-releasing hormone (GnRH). This causes the anterior pituitary gland to produce luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This allows for production of estrogen in the ovaries.

Progesterone

What is progesterone?

Progesterone is a hormone that helps regulate the menstrual cycle and plays a key role in the maintenance of pregnancy.

What controls the release of progesterone?

It starts in the hypothalamus. For progesterone to be released, the hypothalamus first releases gonadotropin-releasing hormone (GnRH). This causes luteinizing hormone (LH) to be released from the anterior pituitary gland and allows progesterone to be produced in the ovaries.

Testosterone

What is testosterone?

Testosterone is a hormone that helps to stimulate the development of male sex organs, and it's also instrumental in sperm production.

What controls the release of testosterone?

Again, it starts in the hypothalamus. For testosterone to be released, the hypothalamus produces gonadotropin-releasing hormone (GnRH). This causes the anterior pituitary gland to secrete the hormones LH and FSH, causing sperm and testosterone production in the testes. You can remember that estrogen and testosterone have the same release process, but in the ovaries and testes respectively.

Oxytocin

What is oxytocin?

Oxytocin is known as the love hormone! ❤️

In the female reproductive system, it causes contraction of the uterus and promotes lactation. In the male reproductive system, it controls production of testosterone and sperm release.

What controls the release of oxytocin?

Most hormones in the endocrine system are controlled through a negative feedback mechanism, but oxytocin is controlled by a positive feedback mechanism. In women, oxytocin is released in response to uterine contractions as well as breastfeeding.

Prolactin

What is prolactin?

Prolactin is a hormone that promotes lactation, which makes it pretty easy to remember. Prolactin, Lactation.

What controls the release of prolactin?

Prolactin is released from the anterior pituitary gland. Levels of prolactin are controlled by levels of dopamine, estrogen, and other hormones circulating in the body.


Full Transcript

In this video, we are going to talk about specific hormones that you definitely need to be familiar with, as a nursing student or a nurse. If you are following along with cards in our Medical-Surgical Nursing Edition 2 package, we are on card number five.

Let's first talk about cortisol. Cortisol is a glucocorticoid that is considered the stress hormone in the body. It has more to do with chronic stress than it does acute stress.

If you're being chased by a bear, that's definitely acute stress, and that would cause the release of epinephrine and norepinephrine from the adrenal medulla. However, if you have more chronic stress, say with nursing school, that can result in elevated cortisol levels.

If you have elevated cortisol levels for a long period of time, that can have some detrimental effects on the body. Including decreased immune function, increased blood pressure, and high levels of glucose in the bloodstream. That is one of the effects of cortisol.

Cortisol has a number of functions in the body, including regulation of metabolism, your immune response, as well as your body's response to stress.

What controls the release of cortisol? It starts in the hypothalamus. So the hypothalamus will produce CRH, which causes the release of ACTH from the anterior pituitary gland. And then this causes the release of cortisol from the adrenal cortex.

We will be getting into dysfunctions that are caused by too much cortisol, such as Cushing's disease, or not enough cortisol, such as Addison's disease. So those diseases will be covered in another video in this playlist.

Next, let's talk about thyroid hormones, T3 and T4. And also just so you know, T3 is the active form of T4. Thyroid hormones control many functions in the body, including metabolism, growth and development, heart function, brain function, muscle function, as well as digestion and bone maintenance.

In terms of what controls release of thyroid hormones, it starts again in the hypothalamus. So the hypothalamus produces TRH, which causes the anterior pituitary gland to produce TSH. And then this allows for production of T3 and T4 in the thyroid gland.

We will be getting into dysfunctions of the thyroid hormones as well. If we have too much T3 or T4, we can end up with hyperthyroidism. And if we don't have enough, then we can have hypothyroidism.

Next, we have growth hormone, or GH. And another name for growth hormone is somatotropin.

Growth hormone controls growth, which is pretty intuitive, and metabolism in the body. And it also controls protein synthesis.

In terms of the release of growth hormone, again it starts in the hypothalamus. The hypothalamus will produce GHRH, growth hormone-releasing hormone, and that causes growth hormone, GH, to be produced in the anterior pituitary gland.

And we will be going over dysfunctions of growth hormones. So if we have too much growth hormone, that's growth hormone excess. That causes problems. And if we don't have enough, that also causes issues that we will be discussing.

Next, let's talk about estrogen. Estrogen is a hormone that stimulates development of female sex organs, and it also is instrumental in the regulation of the menstrual cycle.

We're not going to go into details of the menstrual cycle in this playlist. But we will be talking about it more in my reproductive system playlist.

In terms of what controls release of estrogen, it starts in the hypothalamus. The hypothalamus first produces gonadotropin-releasing hormone. This causes LH and FSH to be produced in the anterior pituitary gland, and then that allows for production of estrogen in the ovaries.

Next we have progesterone. So progesterone also plays a role in the regulation of the menstrual cycle. And it also plays a key role in the maintenance of pregnancy.

The pathway, again - you guessed it - it starts in the hypothalamus where the hypothalamus releases gonadotropin-releasing hormone. This causes LH to be released from the anterior pituitary gland, and this allows for progesterone to be produced in the ovaries.

Now we had testosterone. Testosterone helps to stimulate the development of male sex organs, and it's also instrumental in sperm production.

The pathway - I know you guys are going to get this. Gonadotropin-releasing hormone is produced in the hypothalamus, which causes FSH and LH to be produced in the anterior pituitary gland. And then this allows for sperm and testosterone production in the testes.

Next we have oxytocin. So in females, it causes contraction of the uterus and also promotes lactation. In males, it controls production of testosterone as well as sperm release.

Most hormones in the endocrine system are controlled through a negative feedback mechanism, which we will be talking about at length in another video. Oxytocin, on the other hand, is controlled by a positive feedback mechanism, which we'll also talk about in that video. So in women, oxytocin is released in response to uterine contractions as well as breastfeeding.

Then let's talk about prolactin. Prolactin is a hormone that primarily promotes lactation. So that one is pretty easy to remember, because you have prolactin and lactation.

It is released from the anterior pituitary gland. Levels of prolactin in the body are basically controlled by levels of dopamine, estrogen, and other hormones circulating in the body.

I'm going to stop here. In my next video, we will go over more endocrine system hormones. So stay there with me!


1 Response

Zereu

September 29, 2020

It is very very nice class and more help

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