Endocrine System

Transcript

Hey, guys! Welcome to this Mometrix video about the endocrine system.

The endocrine system plays an important role in our bodies. It regulates several critical functions including growth, reproduction, and stress. In this video, we’ll delve into these different functions and see how useful it is in our everyday lives.

What is the endocrine system?

The endocrine system consists of a series of glands that produce and secrete hormones. Those hormones regulate several human body functions, including growth, sexual function, and reproduction.

The endocrine system contains the pituitary gland, the thyroid gland, the parathyroid glands, adrenal glands, and the ovaries in females and the testicles in males. These glands are in or near a number of organs, including the brain, kidneys, and the pancreas. Let’s take a more detailed look.

Pituitary Gland

The pituitary gland is a small organ with a big responsibility. The gland is only the size of a pea, but it’s referred to as the “master gland” because it secretes hormones throughout your body. These hormones direct body processes or (force) other glands to produce hormones.

The pituitary gland has two parts — the anterior, located at the front of the gland, and the posterior, located on the rear. The anterior and posterior sections each produce specific hormones. Let’s take a closer look at the two.

The Anterior Pituitary

We’ll start with the anterior pituitary, which produces far more hormones than the posterior. We’re going to take a look at nine of these hormones.

Growth Hormone (GH)

First, the growth hormone, or, GH. This hormone stimulates growth focusing on the bones and muscles. GH stimulates growth in children and then, in adults, helps maintain muscle and bone mass.

Prolactin

Number two is prolactin. Nearly 8 in 10 mothers breastfeed their newborn babies, according to the Centers for Disease Control. Prolactin plays a critical role because that’s the hormone that stimulates breast milk production. Prolactin always affects sex hormone levels and fertility in women and men.

Adrenocorticotropic Hormone

Next, we have the adrenocorticotropic hormone. Adrenocorticotropic stimulates cortisol, the so-called stress hormone. It’s also known for controlling the human “fight or flight” instinct and works with the brain to manage emotions like mood and fear. Cortisol also plays several other important roles. It increases glucose, which increases blood sugar. It also regulates blood pressure, boosts energy, and manages the carbohydrate, fat, and protein use in the body. When the body is under stress, it produces more cortisol.

Endorphine

Number four is endorphins. When you feel pain or pleasure, you have endorphins to thank. Endorphins are often referred to as the body’s natural pain-killer, but the hormone is also the body’s pleasure center. The body releases endorphins during periods of stress, including exercise, and works with the brain to lessen our perception of pain.

Enkephalins

Next, we have enkephalins. These are closely related to endorphins because they also release hormones that help control pain.

Beta-Melanocyte-Stimulating Hormone

Number six is the beta-melanocyte-stimulating hormone, this helps protect the skin from ultraviolet radiation. It also can help suppress appetite.

Luteinizing Hormone

For number seven we have the Luteinizing hormone which helps stimulate testosterone production in men and estrogen production in women.

Follicle-Stimulating Hormone

Next, we have the follicle-stimulating hormone, this hormone has a different function in men and in women. In women, the hormone helps produce estrogen and egg growth, while in men, this hormone is critical in sperm production.

Thyroid-Stimulating Hormone

Finally, number nine is the thyroid-stimulating hormone. This is your regulatory machine because it regulates the number of hormones the thyroid releases. It’s critical to metabolism.

Those are the components of the anterior pituitary. Now, we’ll look at the two components of the posterior pituitary.

Posterior pituitary

Vasopressin

First, we’ll look at vasopressin. It’s the hormone that helps the body prevent dehydration by helping you conserve water. That’s why it’s called the antidiuretic hormone.

Oxytocin

Secondly, there’s oxytocin. This one works hand-in-hand with prolactin. While prolactin stimulates breast milk production, oxytocin stimulates the release of breast milk. It also works in the uterus because it helps stimulate contractors during labor.

Now, we’ll move on to some of the other glands in the pituitary.

Thyroid gland

The thyroid gland is located at the base of your neck, and it’s shaped like a butterfly. The thyroid gland controls how your body uses energy. It controls our metabolism but also regulates several bodily functions, including heart rate, breathing, and body weight. The thyroid produces two important hormones: triiodothyronine, called T3 for short, and thyroxine, called T4. Those hormones come from the iodine in the food we eat. When T3 and T4 enter our bloodstream, they regulate how fast our cells and metabolism work. For example, these hormones determine how fast or slow our heart beats and the rate at which our intestines process food. The pituitary gland, along with the hypothalamus in the brain, makes sure T3 and T4 are in balance. If they’re not, that imbalance can cause health issues. For example, too much T3 and T4 can make you nervous and hyperactive. Too little can make you depressed, tired, and result in difficulty concentrating.

Parathyroid gland

As small as the pituitary gland is, it’s a giant compared to the parathyroid glands. These four glands are all the size of a grain of rice. But their small size doesn’t mean they have a small job. You see, the parathyroid glands regulate the body’s calcium levels. You’ve seen those commercials before, the ones that say calcium builds strong bones. Well, they’re right. The parathyroid glands store calcium in our bones, where it’s stored until other parts of our body need it. The glands also control how much calcium our bodies absorb from our food and how much calcium our kidneys excrete.

Adrenal glands

Now, we’ve been in these situations before. Your palms get sweaty, your heart races, and it’s all because of stress. That’s the adrenal glands springing into action. The adrenal glands produce adrenaline, the hormone that triggers the fight or flight response in humans. And while that’s what the adrenal glands are best known for, they have other functions as well. Let’s dive into the adrenal glands and their functions.

There are two adrenal glands, and they both sit on top of your kidneys.

Adrenal Cortex

The adrenal cortex produces cortisol and aldosterone. We covered cortisol, the so-called stress hormone, earlier in the video. Aldosterone has a direct effect on regulating blood pressure because it conserves sodium, secretes potassium, and retains water. The adrenal cortex is located on the outer part of the adrenal gland. Every one of the hormones secreted by the adrenal cortex is vital to life.

Adrenal Medulla

The adrenal medulla, which is the inner part of the adrenal gland, produces several hormones including adrenaline, but the hormones produced by the adrenal medulla are not essential to life.

Now, we’ll move to the male and female reproductive systems.

Ovaries

Women have two ovaries that are critical to fertility. The ovaries, about the size of a large grape, produce eggs that can be fertilized. You might ask yourself why the ovaries are considered a hormone? Well it’s because the ovaries secrete two hormones important to reproductive health — estrogen, and progesterone. Let’s take a closer look at those hormones, starting with estrogen.

Estrogen

Estrogen plays a critical role in female growth, development, and childbearing. There are actually three estrogens that all work together.

Estradiol

First, there’s estradiol. Estradiol helps the female reproductive organs grow. The placenta produces estradiol, which is why estradiol levels rise during pregnancy.

Estrone

Secondly, there’s estrone. If any hormone has ever gotten a bad name, it’s this one. Estrone has been linked to moodiness and weight gain and is produced in a more prominent way during menopause.

Estriol

Lastly, there’s estriol. Estriol comes into play during pregnancy, when the body releases the hormone into the bloodstream. Estriol helps nourish the baby and the placenta. After birth, estriol levels in the body drop.

Progesterone

Progesterone also plays an important part during pregnancy. After ovulation, progesterone helps get the uterus ready for a fertilized egg by thickening the uterine lining. If there’s no fertilized egg present, the level of progesterone drops and then menstruation begins.

So those are the female hormones. Now, let’s talk about the male hormones.

Testes

The testes produce testosterone, a hormone critical to the physical development of boys. During puberty, testosterone production results in several body changes, including a lower voice, growing facial hair, becoming taller, and increasing muscle mass. As men, testosterone aids in sperm production, maintains strength and mass, and maintains sex drive.

That’s our overview of the endocrine system. It regulates several critical functions in our body, including growth, reproduction, and stress.

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