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

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!