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Endocrine System 101_Final

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>> Hey there, welcome. I know you are interested in learning all about hormones since you signed up for a course in hormone health so we're not going to waste any time. To officially kick things off, I am going to lead you through a basic overview of the structure and function of the endocrine system. We'll talk about its role in the body, and the main functions that are carried out by this fascinating and complex part of the body. This is an important place to build your foundation because when we talk about hormone health we're talking about the chemicals and processes that occur within the endocrine system. Now I'm sure you've heard of the endocrine system, but how much do you know about it? Whether you are just starting out or you already know a wealth of information on the topic, there's much to learn about how the endocrine system operates, and how it affects all the other systems in the body. There are many parts of this system that work together in an amazingly coordinated way. Developing a working understanding of this intricate dance and the dancers who star in the show will provide an important context for understanding hormone health as it affects your clients. So we're going to start off here with a little anatomy lesson. Ready? You can think of the endocrine system as a collection of endocrine glands that produce hormones that are used as chemical messengers throughout the body to help regulate vital processes including metabolism, growth, sleep, and reproduction. It's kind of like the postal service. Each gland is like a post office and the hormones from these glands are like the mailman, delivering important messages from the post office to the homes they're addressed to. Endocrine glands regulate each of the body's main functions by triggering a complex dance. The two lead partners in this dance are the hormones produced by each of the endocrine glands and specific receptor cells in the target organs. As their name would imply, these receptor cells receive the messages delivered by the hormones. They are super sensitive and respond to even the tiniest amounts of hormones. So as you can see, it's important that they're delivered to the right place. A good way of picturing the relationship between hormones and their receptor cells is to think of a lock and a key. Each specific hormone is like a key to its matching receptor cell, just like there's only one key to unlock a door, there is only one specific hormone that can bind to a certain type of receptor cell. When a hormone binds to its target cell, it initiates a response from the cell that performs the desired function in the body. Essentially, the hormone is tapping the receptor cell on the shoulder and saying, "Hey, friend, it's time to get to work. Go, do your job." As a whole the endocrine system is composed of endocrine glands and a few key glandular organs. These include the pituitary gland, thyroid gland, parathyroid glands, thymus gland, adrenal glands, pancreas, ovaries in women, testes in men, pineal gland, and hypothalamus. Hormones secreted from endocrine glands are special. Why is that? Because unlike substances secreted by other glands, they're released directly into the body. Endocrine hormones are transmitted through the bloodstream to their specific destinations in the body through a process called diffusion. Going back to our postal service analogy, diffusion would be the mail truck and the bloodstream the road. Let's compare this to how other glands work. Sweat glands and salivary glands, for example, secrete the substances they produce through ducts. And the substances they produce can only be used in the vicinity of that gland. Endocrine glands can transmit their hormones using diffusion to any part of the body. Pretty cool, huh? Okay, before we move forward, let's recap what we've learned so far. The endocrine system is made up of glands that produce hormones which transmit messages to different parts of the body to carry out the major functions of living. These hormones travel directly through the body by a process called diffusion, to bind to a specific receptor cell to send it a chemical message to do its job. Now that we're clear on what the endocrine system is as a whole, let's take a look at the specific roles of the nine major endocrine glands. The pituitary gland. This gland is only the size of a pea but it's mighty. The pituitary is often referred to as the master gland because it produces hormones that control other parts of the endocrine system, from the thyroid gland to the adrenal glands, to the ovaries and testes. Pretty impressive for a little guy. The pituitary is located at the base of the brain under the hypothalamus. These guys are neighbors because they work very closely together. The pituitary has two parts, the anterior lobe and the posterior lobe. The anterior lobe produces and releases hormones. The posterior lobe releases hormones produced by the hypothalamus into the bloodstream. The anterior lobe is like a factory where hormones are produced, and the posterior lobe is like the delivery truck that sends them out to where they need to go. Like a good neighbor, the hypothalamus lets the pituitary know when it's time to get to work. In case you were wondering, the hypothalamus is the part of the brain that acts as a link between the nervous system and the endocrine system. It signals the pituitary gland to either hit the gas or the brakes on hormone production. In the hormonal symphony, the hypothalamus is the conductor, the hormones are the music notes, and the orchestra is the pituitary playing the music as instructed by the conductor. The pituitary gland produces eight different hormones. Here is a quick run through of each. Adrenocorticotropic hormone or ACTH, which stimulates the adrenal glands to produce hormones. Follicle-stimulating hormone, also known as FSH, which ensures that the ovaries and testes are functioning properly. Luteinizing hormone or LH, which works together with FSH to help ensure the normal functioning of the ovaries and testes. Growth hormone, which is essential during the early years of development to maintain healthy body composition. In adults, growth hormone aids in bone growth and development, building of muscle mass and fat distribution. Prolactin, which is best known for stimulating breast milk production but also plays an essential role during pregnancy and the development of a fetus. Prolactin also supports metabolism and immune system function. Thyroid-stimulating hormone or TSH, which stimulates a thyroid gland to produce hormones. Antidiuretic hormone, which prompts the kidneys to increase water reabsorption from the urine into the blood. And oxytocin, which is involved in a variety of processes, including stimulating the production of breast milk and lactating moms. It's also known as the cuddle hormone because it promotes bonding. Got all that? Don't worry about memorizing it. We're just introducing all of these parts and concepts to you today to get your feet wet. As you learn more about the glands and hormones of the body as we progress through this course, it will all start to sink in. Let's move on to the next one, the hypothalamus. As I mentioned, the hypothalamus is a close friend and neighbor of the pituitary gland. The hypothalamus takes in information from the nervous system and delivers messages to the endocrine system. Think of it as the liaison between these two systems. How does it do this? Great question. The hypothalamus receives cues about what's going on from the nervous system. In response, it secretes neurohormones which are substances that signal the pituitary gland to secrete specific types and amounts of hormones for use in the body. This dance between the nervous system, the hypothalamus, and the pituitary is critical because it's responsible for maintaining homeostasis, which is the body's internal balance. Homeostasis affects nearly every system in the body including circadian rhythm, body temperature, appetite, heart rate, blood pressure, and fluid, and electrolyte balance. Many of the hormones secreted by the hypothalamus exist just to participate in this spectacular dance. Their job is to signal the pituitary to release or inhibit a particular hormone. These hormones include thyrotropin-releasing hormone, growth hormone releasing hormone, growth hormone inhibiting hormone, commonly known as somatostatin, gonadotropin-releasing hormone, and corticotropin-releasing hormone. The hypothalamus also secretes oxytocin, dopamine, and antidiuretic hormone, commonly known as vasopressin. You're likely familiar with the next gland we'll be covering, the thyroid gland. The thyroid is a butterfly shaped gland located in the front of the neck. Its essential function is to regulate the body's metabolism, the process of using food as energy. Every cell in the body depends on the hormones your thyroid produces for metabolism regulation. It works like this. The pituitary gland senses when thyroid hormones dip too low. When this happens, it produces thyroid-stimulating hormone or TSH in response. TSH does exactly what its name suggests. It stimulates the thyroid to produce more of these essential hormones. In order to do its job, the thyroid needs help from iodine which comes from your diet. This is why it's really important to consume enough of this nutrient. Thyroid cells absorb iodine and combine with an amino acid called tyrosine to make thyroxin. This is better known as T4. They also produce triiodothyronine, also known as T3. Aren't you glad we have an abbreviated name for that one? Once produced, these hormones are released into the bloodstream and transported through the body where they control every aspect of cell metabolism. Next up is the parathyroid. Judging by its name and location, you think that the parathyroid is related to the thyroid, but there is actually no related function. The purpose of the parathyroid is to control blood calcium levels, keeping them in a very specific range. There are actually four of these tiny vascular glands and their job is to constantly filter the blood. If they detect that blood calcium levels are too high or too low, they'll react by producing more or less parathyroid hormone known as PTH for short. Parathyroid hormone has an influence on your bones and causes them to release calcium into your bloodstream if levels get too low. Our bodies need the right balance of blood calcium levels to maintain bone health and density. Blood calcium levels also regulate muscle contraction and contribute to the conduction of electrical currents along the nerves. Important stuff to have working, right? When calcium levels get too high or too low, it can have detrimental effects on energy, sleep, and cognitive function. Our next gland is the thymus gland. This gland is actually part of the immune system but it's worth including in our discussion. The thymus gland is located behind the sternum between the lungs. It produces a hormone called thymosin which stimulates the development and production, a very important disease fighting white blood cells known as T lymphocytes or T-cells. These T-cells help protect the body from diseases and infections. Here's an interesting fact. The thymus gland is largest when we were children and it's only active until puberty. Once puberty ends, it begins to shrink and then turns into fat. The adrenal glands, these glands are located right above the kidneys. They're best known for regulating the body's response to stress. The adrenal glands are part of the hypothalamic-pituitary-adrenal axis, better known as the HPA axis. These three endocrine glands form a complex feedback loop to regulate hormone production and use. The adrenal glands actually do much more than battle stress. They also release hormones that are essential to life, including cortisol, which is considered one of the main stress hormones. Aldosterone, which helps regulate blood pressure and maintain the body's PH and electrolyte levels, small amounts of male and female sex hormones, norepinephrine and epinephrine, also known as adrenaline, act as neurotransmitters and hormones in the body. These are the chemicals that contribute to the stress response by increasing heart rate and blood pressure so the body can pump blood efficiently. They also increase respiration for better delivery of oxygen to your cells and aid in the removal of carbon dioxide. These hormones also free up some stored glucose so the body can use it for energy. Basically, these two chemicals give the body everything it needs to run or fight. Next up is the pancreas, a glandular organ that serves a couple of different functions. The pancreas is better known for its role in digestion excreting digestive enzymes to break down the nutrients in your food. But did you know the pancreas also functions as a hormone producing endocrine gland. It produces the hormones insulin and glucagon, which help control blood sugar levels throughout the day. Glucagon raises blood glucose by stimulating the liver to turn glycogen, which is stored glucose into glucose molecules to be released into the bloodstream. Glucagon can also convert fat cells into glucose for the body to use as energy. On the flip side, insulin is released to help lower blood sugar levels. It does this by converting glucose into its stored form glycogen, which is stored in the liver muscles and fat tissue. Next we have the gonads. These are the ovaries in women and the testes in men. Both act as endocrine glands secreting important sex hormones. The ovaries are responsible for producing the two main sex hormones in women, estrogen and progesterone. The testes produce androgens or male hormones, namely testosterone. In both men and women, the gonads produce hormones in response to messages from the pituitary gland. We'll cover the male and female sex hormones in-depth later on in this course. Lastly, we have the pineal gland. The pineal gland is a small pinecone-shaped gland located in the brain. Its functions include converting signals from the nervous system into hormones and influencing sexual development. But its main function is the production of melatonin, the body's main sleep hormone. Melatonin is regulated by a signal that originates from the retina in the eye. The retina is sensitive to light and darkness. When the pineal gland receives the signal that it's night time, it uses serotonin to create melatonin. Higher levels of melatonin promote sleep, while lower levels during the day help us stay awake. Clients who have trouble falling or staying asleep at night may not be producing enough melatonin in the evening. And there you have a broad overview of the immensely complex but fascinating endocrine system. To recap, the endocrine system is the network of glands that produce hormones that regulate all bodily functions. Specifically, the endocrine system is made up of the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries or testes, pineal gland, and hypothalamus. Each of these secretes different hormones that serve specific functions in the body. They all work together in a perfectly coordinated fashion to keep our bodies functioning properly. I hope this overview was helpful in forming a basic understanding of the endocrine system. Now I know this is a lot of information but there's no need to feel overwhelmed. Working with hormone health involves learning about all of the hormones themselves, and the glands, and structures that produce them. There is no way to cut it. It's a lot of information, but you're not expected to memorize it all, and it doesn't all have to click for you at once. So if you feel like you can't remember everything we just covered, don't sweat it. Instead, head on over to the Facebook group to talk about what you just learned. Was there something that stood out to you in this lecture? Is there a particular gland or hormone you're particularly excited to learn more about? We'd love to hear your thoughts. Thanks so much for watching, and I'll see you soon.

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Duration: 16 minutes and 20 seconds
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Language: English
License: Dotsub - Standard License
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Posted by: ninaz on Mar 23, 2018

Endocrine System 101_Final

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