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Anatomy and Physiology of the Adrenal System_Final

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>> Hey there, great to see you again. In this lecture, we're going to be talking about one of the most important aspects of hormone health, the adrenal system. The adrenals are very small but pack a big punch. They're barely bigger than a walnut and sit just above the kidneys on either side of the abdomen. For such a small organ, they're able to perform an amazing number of functions. The adrenals are an important part of the hypothalamic-pituitary-adrenal axis also known as the HPA axis. The adrenals influence reproduction, appetite, blood sugar control, stress management, growth, and digestion. Pretty much every process in the body is affected by the adrenals. And they're fast, designed to respond to life or death situations, the adrenals can go from 0 to 60 in seconds. Think of them as a fancy sports car. Your adrenals are a hormone accelerator that slam a pedal to the metal when you need that extra energy to overcome a threatening situation. Whether you are escaping from a burning building or just rushing to get to work, your adrenals are helping you get where you need to go. They're what keep you going when the going gets tough. So as you can imagine, adrenal dysfunction has become an epidemic in our modern fast-paced world. When a person is chronically stressed, the adrenals keep the gas pedal pin to the floor until eventually they burn through all the available fuel in their tank. When this happens, the whole system comes to a halt, just like when you run out of gas in a car. Let's take a look at the physical makeup of the adrenal glands. The adrenal glands are made up of two layers, the adrenal cortex and the medulla. First, we'll talk about the adrenal cortex which is the outer layer. It's divided into three zones. Each zone makes and secrets a different set of hormones, each with a distinct function. Here's an easy way to remember the three zones, salt, sugar, and sex. This is in reference to the types of hormones each zone is responsible for producing and the specific roles and functions involves. The outermost zone, the salt zone produces hormones that help regulate salt balance in the body. One of these hormones is called aldosterone. This hormone is critical for proper cell and nervous system function. When not enough aldosterone is produced, it can cause life threatening dehydration, low blood pressure, and kidney failure. The middle zone, the sugar zone produces the glucocorticoids, such as cortisol and corticosterone. Cortisol is the strongest of these and the most commonly produced. Corticosterone is minimally produced and is much weaker. The glucocorticoids work to increase blood sugars so that a person has enough energy to respond quickly to a threat. The third and deepest zone, the sex zone, produces a several male sex hormones. These include DHEA, DHEA sulfate also known as DHEA-S, and androstenedione. These less active male hormones are produced in the adrenal cortex and then converted in the body to testosterone and estrogen, the more active forms. This zone also produces small quantities of the female sex hormones, progesterone and estrogen. So to recap what we've covered so far, the three zones of the adrenal cortex are responsible for maintaining adequate levels of salt, blood sugar, and sex hormones, the three Ss. Now let's talk about the inner layer of the adrenal glands, the medulla. The medulla produces epinephrine also known as adrenalin as well as norepinephrine and dopamine. These are the hormones that react to manage physical stress responses. They belong to a class of hormones called neurotransmitters, which means they have a direct effect on the nervous system. There are nerves that run directly into the adrenal medulla from the spinal nerves. When these nerves stimulate the medulla, large amounts of neurotransmitters are released and have wide-reaching effects on the body, shutting down processes that aren't required in the heat of the moment, like digestion and reproduction, and firing on processes that are like blood pressure and heart rate. This is commonly referred to as the fight or flight response. One of the major functions of the adrenal glands is to respond to all types of stress. Second to the brain, the adrenal glands are the body's next line of defense against stress. When a person experiences a stressful event, the amygdala, an area of the brain that contributes to emotional processing, sends a distress signal to the hypothalamus. This area of the brain functions like a command center. It communicates with both the nervous system and the endocrine system, acting as liaison between these two systems. The hypothalamus then talks to the adrenal glands using the hormone ACTH and tells them to release the appropriate hormones. This is how the body literally copes with stress. Okay, so now let's think about the different types of stress. Did you know that stress can be either physical or psychological or both? Physical stressors include injury, temperature extremes, illness, and malnutrition. Psychological stressors include fear, conflict, anger, frustration, and grief. Additionally, the body responds differently to short-term stress and long-term stress. Short-term stress, such as swerving to avoid a car veering into your lane on the highway, causes something called the alarm reaction. This fight or flight response begins with hormones epinephrine and norepinephrine being released from the adrenal medulla. These hormones prepare the body for extreme physical exertion. However, short-term stress is quickly relieved and the body can return to normal with little to no harm done. But if the stress persists, it becomes long-term stress and the brain that keeps sending the signal to make more cortisol. Long-term stress includes such things as ongoing marital problems or working in a toxic job environment, this is undesirable because the body often can't keep up. Eventually, it goes into a state of exhaustion because we're just not designed to have high levels of cortisol in the long run. When this kind of chronic stress is present, you may notice your clients experiencing depression, immune suppression, and even severe fatigue, it's this kind of stress that can eventually lead to a fatal heart attack. Cortisol has many effects in the body that are helpful in the short-term, but it can be damaging in the long-term. Effects of cortisol on the body include, one, decreased inflammation. Now this may come as a surprise because, typically, we think of people with elevated cortisol is having high levels of inflammation. This is true in the long-term, but it's actually not the cortisol producing the inflammation. You see, cortisol is an anti-inflammatory, and in small amounts it blocks the early stages of inflammation. It also helps resolve inflammation that's already in progress. This is great in the short-term, but overtime the body produces proinflammatory cytokines to counter the inflammation suppressing effects of the cortisol. This can lead to inflammatory diseases, like Crohn's and rheumatoid arthritis for susceptible individuals. Two, increased blood sugar. Cortisol encourages the liver to create and store sugar. This results in an increase in blood sugar as well as increase sugar stores in the liver. Over time, this can lead to insulin dysregulation, insulin resistance, and even diabetes. Three, decreased muscle and protein levels. A high level of cortisol is not your fitness pal. Elevated cortisol decreases protein stores in the body by inhibiting the production of protein and stimulating the breakdown of muscle protein. In the long-term, this can lead to a chronic state of muscle breakdown and reduce muscle mass. Four, decreased immune response. Cortisol also has the undesirable effect of suppressing immune response. This is why chronically stressed people are more susceptible to illnesses, like the flu. Remember, almost every gland in the endocrine system works in a complex feedback loop and the adrenals are no different. When the hypothalamus senses that there is too little cortisol, it tells the pituitary to produce more ACTH which drives the adrenals to make more cortisol. When there is too much cortisol, ACTH production shuts down. When the system is working well, cortisol is kept in a very fine balance meeting the needs of the endocrine system. However, within just a few minutes of the occurrence, a stressful event causes a rapid release of ACTH which results in an equally rapid release of cortisol. Stressors that cause rapid cortisol release include trauma, infection, temperature extremes, surgery, debilitating disease, and feeling emotionally stressed. Well, cortisol does have many beneficial effects for dealing with short-term stress, if levels remain high, there are number of undesirable side effects that can occur. Unwanted effects of long-term cortisol elevation include poor wound healing, stomach ulcers, diabetes, weakness and muscle wasting, depression, yeast overgrowth, and bone loss. Something interesting to keep in mind when working with clients who struggle with their weight is that their body may be sending signals to the GI tract to absorb more nutrients from food. This can make them gain weight, especially around the waistline. You may have heard of that apple shaped figure that tends develop in people who are chronically stressed out. This is because fat cells in the body of that area have more cortisol receptors. Compounding this matter, these folks tend to be sensitive to high levels of insulin and are very affective at storing energy. Unfortunately, this is not a good place to gain weight because, beyond appearances, it's associated with heart disease, metabolic syndrome, and diabetes. Well, what does all of this mean? If your client is super stressed, it might be really hard for him or her to lose weight, no matter how much they're working out. This type of science goes beyond calories in, calories out. For these clients, you want to help them manage their stress through lifestyle changes in order to help them meet their weight loss goals. Before we move on, let's quickly recap. We described the physical structure of the adrenal glands and the hormones produced by each of the adrenal zones. We also covered the difference between short and long-term stress, as well as the harmful effects of cortisol on the body over a long period of time. Now we're going to switch gears and focus in on the adrenal hormones themselves. Specifically, we'll take a look at how DHEA, and DHEA-S, and epinephrine effect the production of sex hormones. Let's begin with DHEA which is the building block for the sex hormones. Many of the sex hormones including the estrogens and testosterone are produced from DHEA. So it follows that there needs to be an adequate amount of DHEA in order for them to be made. DHEA and cortisol balance each other. DHEA blocks the effect of cortisol and cortisol does the same to DHEA. Think of it like a seesaw, if cortisol is high, DHEA levels are low. DHEA also appears to play a role in anti-aging, which is why it's often referred to as the fountain of youth hormone. It's been shown to improve heart disease, dementia, immune deficiency, cancer, and osteoporosis. DHEA may also help your clients control their weight. It influences the fat cells telling them to stay small. It's also been shown to convert cortisol to cortisone which is a weaker glucocorticoid. That means it is when DHEA is higher, it helps reverse the weight gain effect of cortisol. Awesome, right? DHEA-S is a weak male sex hormone similar to DHEA. Increased levels of DHEA-S maybe seen with amenorrhea. High DHEA and DHEA-S levels are also seen in polycystic ovarian syndrome. Next, let's discuss epinephrine which is also called adrenaline and is released from the adrenals. Strong emotions, such as fear or anger cause epinephrine to be released into the bloodstream. This causes an increase in heart rate, muscle strength, blood pressure, and blood sugar. Epinephrine is what's behind that super strength when people need to lift a car to save their baby or power through to cross the finish line and beat their opponent in a race. Both epinephrine and norepinephrine signal the liver and skeletal muscle cells to release glucose, resulting in increased blood sugar levels. The heart rate, pulse, and blood pressure increase to prepare the body to fight or run. Oxygen levels in the blood are raised and blood vessels dilate to allow more flow of oxygen and blood to the lungs, brain, heart, and skeletal muscles. At the same time, it tightens the blood vessels serving less essential organs, such as the GI tract, kidneys, and skin so they become less active funneling all of the attention to the organs needed to respond to the threat. Other effects include a dry mouth, loss of appetite, pupil dilation, and loss of peripheral vision. These effects help create an optimal state in response to danger or an acutely stressful event. Now you know how the adrenal hormones affect sex hormones. But do you know how they affect menstruation and fertility? As you might imagine, stress levels greatly impact both of these vital processes. In order to maintain a healthy menstrual cycle, the adrenals must be working properly. The balance of DHEA and cortisol is important to keep the cycle running smoothly. When too much cortisol is being produced because of stress, the DHEA level goes down and the body produces less progesterone and estrogen. This can cause amenorrhea and irregular periods as well as increasing the risk of infertility. Estrogen is essential to normal periods. The pituitary gland releases follicle-stimulating hormone or FSH at the beginning of the menstrual cycle. This signals some of the follicles in the ovary to begin maturing. As the follicles begin maturing, they release the hormone estrogen. The rising estrogen levels then signal the pituitary gland to slow its release of FSH. Estrogen levels continue to rise which signals the pituitary gland to release luteinizing hormone or LH. LH surges signaling the follicle to open and release the mature egg. This is called the ovulatory phase. Estrogen levels peak during this time and progesterone begins to increase as well. Progesterone is crucial for fertility. The follicle that release the egg turns into a progesterone making machine once ovulation occurs. Without ovulation, the body produces much less progesterone. Progesterone is beneficial for mood, metabolism, and hair, and bone health. It's important to fertility because it maintains the line of the uterus, making it possible for a fertilized egg to attach and survive. Now something interesting to know is that cortisol can steal progesterone. Cortisol and progesterone both come from the same precursor hormone called pregnenolone. When the body has to make a lot of cortisol to deal with stress, two things can happen, one, the adrenals can make in or, two, the body can break down progesterone to form cortisol. If the adrenals are maxed out on production, the body steals both pregnenolone and progesterone in order to make enough cortisol to deal with the stress. This phenomenon is called pregnenolone steal. Normally, pregnenolone is used to make the sex hormones. In the case of chronic stress, more pregnenolone needs to be diverted to produce enough cortisol to meet the demand. So when pregnenolone is being used for cortisol production, the production of sex hormones suffers. This is why long periods of stress can be so detrimental to a woman's menstrual cycle function and fertility. It's also why your sex drive can plummet if you're stressed out. If you have a client who is struggling with low libido or often not feeling in the mood, it might be helpful to pay close attention to their stress load as a possible reason for what's causing their lackluster sex drive. Cortisol can also block progesterone causing estrogen dominance, as if pregnenolone steal is in bad enough, high levels of cortisol can also decrease progesterone's ability to get into the cells. Cortisol and progesterone are very similar molecules, so they compete for the same receptors in the cells. Hormones fit into a cell receptor like a key into a lock. If cortisol makes its way to the progesterone receptor, the lock is now occupied and unavailable, and the progesterone molecule becomes blocked from getting into its own receptor. This means that sustained high levels of cortisol can decrease progesterone's ability to get into the cells. This sets the stage for estrogen dominance which can then also cause PMS symptoms, such as irritability, breast pain, acne, and headaches. So as you can see, the proper balance of cortisol and DHEA is critical to supporting fertility and the menstrual cycle. And imbalance of one hormone creates a domino effect that throws other hormones out of balance which can result in poor and unpleasant symptoms like those just described. That wraps up a review of the anatomy and physiology of the adrenal glands. Let's recap what we covered in this lecture. First, we talked about the structure and function of the adrenal system. We went over the hormones that are produced by the adrenal glands and their specific roles in the body. In particular, we took a close look at the effects of cortisol. Finally, we discussed the impact of the adrenal hormones on sex hormone production, menstruation, and fertility. As you can see the adrenals maybe small, but if they start to malfunction, there can be far reaching implications for the entire endocrine system. For many people today, the cortisol surge never turns off and they exist in a constant state of stress. As a Health Coach, it's important to understand why this is happening, so you can educate your clients and help them adapt better lifestyle patterns that can reduce the stress they experience in their daily lives. Take a minute to reflect on your lifestyle. How are your stress levels? And what is your routine like? Are you constantly on a go doing and checking things off the list? Or do you live a more balanced life? Head over to the Facebook group and let us know what's going on for you. This is a great opportunity to discuss self-care and support one another with suggestions and encouragement. Thanks so much for watching and we look forward to see you in the next lecture.

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Duration: 22 minutes and 11 seconds
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Language: English
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Posted by: ninaz on Mar 25, 2018

Anatomy and Physiology of the Adrenal System_Final

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