our last piece of the lecture for um this first week of class and from here on in um starting now and then finishing with next week what we're going to do is talk about the different glands of the um endocrine system the hormone they produce and in some cases most cases what that hormone's action is in the body so here's an overview of what that is we saw this picture of the first uh back at the beginning of this lecture so we have the hypothalamus pituitary gland and pineal gland housed in the brain we have the thyroid gland is this butterfly shaped gland in the neck the thymus gland which is um excuse me inferior to that we have the adrenal glands that sit on top of the kidneys these are the kidneys the pancreas this location in this picture isn't great um and then ovaries and testies so today all or for this lecture all I'm going to address are the hypothalamus and pituitary gland and then starting next week what we'll cover um are the rest of these glands okay so let's start with the hypothalamus and pituitary gland relationship which just means that these two glands are connected and so if I'm um if I was to make a terrible drawing of the brain because that's all I could possibly do um there's my brain and the hypothalamus um somewhere deep inside um the tissue and then this is the hypothalamus my little pink circle hypothalamus and there's this little stock that comes out of or off of the hypo Fus that stock is called the infundibulum which I don't think I have written here in I NF i n dulum d [Music] i that's the spelling in nium I and in case you can't H read my amazing curses that I'm doing with the mouse of my computer um i n f i n d i e u l infundibulum and at the very base of the infundibulum is the pituitary gland all right I'm drawing it a little bigger a lot bigger probably like it's a lot smaller than the hypothalamus but I just want to I'm actually just not GNA blow this up now okay so now the pituitary gland all right the pituitary gland is split into the anterior lobe of the pituitary gland and the posterior lobe of the pituitary gland um the posterior lobe of the pituitary gland um releases two hormones which I'll talk about on the next slide and the two hormones that are released from the posterior lobe are actually made in the hypothalamus and then they are transferred into the posterior lobe of the pituitary and stored two of those they're oxytocin and antidiuretic hormone again I'll talk about those in a second so there's two hormones that are stored in the posterior lobe of a pituitary gland they're made in the hypothalamus stored in the posterior lobe and then when the body needs them the hypothalamus stimulates the posterior lobe of the pituitary to release those hormones the anterior lobe of the pituitary let's just denote it like this maybe um the anterior lobe makes its own hormones so they are not made in the hypothalamus and um and then still for many of those hormones that are made there the hypothalamus tells the anterior Lo of the pituitary when to release them so the hypothalamus and the pituitary gland have a very close relationship and let's continue looking at the posterior lobe hormones okay so these again are hor hormones that are made in the hypothalamus and then stored in the posterior lobe there are two of them the first is called oxytocin an oxytocin um does two things one it stimulates uterine contraction during child birth and two it is also secreted in higher amounts in women that are nursing and helps with the let down of milk while breastfeeding so those are the two functions of oxytocin um the other hormone that is made in the hypothalamus and stored in the posterior loob of the pituitary gland is called antidiuretic hormone or we call it ADH anti-diuretic hormone or ADH here's where we get ADH anti Di IC hormone okay ADH ADH is secreted when we are dehydrated when we're dehydrated so when we are dehydrated the thalamus stimulates the um the posterior L of the pituitary to release anti-diuretic hormone the only cells in the body that are target cells for ADH are cells in the kidney so the kidneys hold whole job in the body which we're not going to get to for a long time and so let's just I'm going to give you a general statement here and that is that the kidney's whole job is to create urine so to do that the kid the kidney like all of our blood supply flows through the kidney about every 20 to 30 minutes and the kidney filters the blood supply anything we don't need anymore gets moved into the urine and anything we still need gets pushed back into the blood so back into the body so when we're dehydrated cells in the kidney will hold on to more water they'll let less water Escape in the urine and they'll retain more water for the body when we're hydrated the kidneys push more water into the urine allow more water to escape and retain less because we just don't need it at that time so when we're dehydrated let's see I'm going to say we're dehydrated this is a hormone we're going to talk a lot about so I'm going to spend a second here when we're dehydrated um a message is sent to the brain to the hypothalamus message is sent to the hypothalamus which is in the brain um that word hydrated [Music] hypothalamus um the hypothalamus tell the posterior I'm just going to say lobe of the pituitary PP posterior pituitary to release ADH the target cells for ADH are in the kidney so remember a hormone is going to move through the blood so every cell in the body has access to it but only cells that have receptors for it will be will be like um activated by it and so and those cells we call target cells and so the only cells in the body that respond to ADH are the kidney cells in the kidney the kidney's response is to retain water allow less water sorry about my handwriting again retain water H2O and so what ends up happening or like the the evidence that we have that this is happening is that our urine becom a very dark yellow there's less water in it and there's more waste material in it um and so it looks very dark yellow when we're dehydrated and that's because our body is pulling water back retaining water in the body less it's escaping so we retain water and also the other thing that happens when we're dehydrated is that The Thirst mechanism in our brain is stimulated we become thirsty and so generally if we are responsive to that we we will drink right so not only not only are we pulling water back into the body from the kidney but we're also adding water and so then we become hydrated right hopefully because we're drinking and retaining water we become hydrated um and so this when we're hydrated the hypothalamus receives a different message right that we're hydrated and so then I'm going to do this in different color [Music] then it would stop sending the message to the posterior pituitary to secrete ADH ADH is no longer secreted and so now the kidney is going to allow more water to pass in the urine we don't need to retain water anymore and we can exist like that as long as we stay hydrated but when we get dehydrated again the hyalinus kicks the message down to the posterior pituitary to release and anti-diuretic hormone which acts on the kidney and tells the kidney to retain water so that's the way anti-diuretic hormone functions all right now the anterior pituitary anterior lobe of the pituitary gland this is commonly called the master endocrine gland because it makes many different hormones and here they are there's 1 2 3 four five six of them um we're going to go we're going to go through them one at a time um so they're listed here for you we're again we're going to go through them one thing I want to say here is that some of these hormones are what we call Tropic hormones or tropins a Tropic hormone is a hormone that instead of going out into the body and stimulating cells to activate or change their activity at the moment a Tropic hormone goes out into the body and stimulates a different gland to secrete another hormone so instead of having action on a cell it has action on a different gland to secrete a second hormone and so I'll show you what that means but the hormones in this list that have the two stars next to them are Tropic hormones so most of these hormones that are coming from the anterior lob of the pituitary are Tropic hormones growth hormone is not and prolactin is not the rest of them are um I will say right now I'm not going to say anything more about prolactin other than its function is to stimulate milk production in nursing women and so in women that are breastfeeding um both prolactin and oxytocin stimulate milk production and the let down of milk um so those hormones are very active so what we're going to do now is go through the rest of these hormones these five we'll start with growth hormone again growth hormone is not a Tropic hormone so it's going to go out into the body and have a direct effect on cells um and its effect is exactly what its name implies its effect is to cause tissues to grow undergo mitosis and the target cells for growth hormone are mostly bone and and um bone and skeletal muscle cells um and the way that growth hormone can stimulate growth in bone and muscle is by keeping the amounts of protein sugar and fatty acids increased in the blood supply so when growth hormones on board like in growing teenagers let's say or in children all the way up through until growth plates close in a person but the rate of growth is accelerated during the teenage years and that's that's why I was ref ing that anyway all through the growing years um this hormone is increasing the amount of all these nutrients in the blood so that tissues have mostly bone and skeletal muscle tissue have access to what they need to grow so let's say there's no growth hormone on board and a child is trying to grow um there then would be less let's say like amino acids running around in the blood you know the building blocks of protein are amino acids bone and skeletal muscle is made of protein so even though a tissue might be trying to grow if the building blocks for that growth aren't around then it can't so growth hormones job or function is to make sure that there's um blood levels of fatty acids increased blood levels of glucose and increased blood levels of amino acids around so the growth can take place okay thyroid stimulating hormone we are going to talk about this one in a lot of depth next week during lab so um I'm going to spend a little bit of time here um thyroid stimulating hormone is abbreviated TS TSH thyroid stimulating hormone this is a Tropic hormone meaning it is released by the anterior load of the pituitary gland and instead of going out to the whole body and causing a response in cells it goes to the thyroid gland and stimulates the thyroid gland to secrete another hormone called thyroid hormone so that's why it's a Tropic hormone here's the whole pathway though um we said that what happens is the hypothalamus stimulates the anter anterior pituitary to release this these hormones so here's how it does that for thyroid the hypothalamus releases a hormone called thyroid releasing hormone or TR TR the only target cells in the body for TR are cells in the anterior lobe of the pituitary gland when those are targeted um and they respond by releasing TSH thyroid stimulating hormone that's released the only target cells in the body for that hormone are cells in the thyroid gland and the action when TSH binds to the thyroid gland the action now becomes thyroid gland releases thyroid hormones there's two thyroid hormones we'll talk about that next week we call them T3 and T4 but regardless the thyroid gland now releases thyroid hormones which act the target cells for thyroid hormone are all over the body it's probably one of the most most widespread acting hormones we Happ to make and so anyway these hormones go out they they act on many many different kinds of tissues in the body so that's the pathway when thyroid hormones are low in the body TR is released causing TSH to be released causing more thyroid hormone to be released now blood levels of thyroid hormone are coming up when when blood level of thyroid hormone come up above a certain amount and the set point for that certain amount is in the brain in the hypothalamus so when thyroid levels in the blood are good enough within the range of homeostasis here's the feedback mechanism when thyroid levels are high it does two things one it turns off the release of TR from the uh hypothalamus and also turns off the release of TSH from the anterior pituitary both of those hormones now shut down and so now the thyroid gland is not receiving the message to make more thyroid and the production of thyroid hormone slows down and or maybe stops now blood levels start to decrease when blood levels of thyroid hormone go below the range of normal all of a sudden now this the thyroid I mean sorry the hamus is stimulated to make more TR which stimulates the anterior pituitary to make more TSH which stimulates the thyroid to make more thyroid hormone s because there's two of them and the levels come back up into our normal range of homeostasis okay when levels are high enough this inhibitory response happens where the anterior pituitary stops making TSH and the hypothalamus stops making TR so the pathway shuts down and the thyroid gland stops making thyroid for a minute when levels go too low this pathway is stimulated again okay thyroid hormone so both TR and TSH are Tropic hormones they are both stimulating another gland to release a hormone instead of the hormone going out and acting on a cell okay next adrenocorticotropic hormone what there is wrong name here's where we get the abbreviation adreno corticotropic um Tropic hormone so adreno corticotropic hormone a again the name is right in here it is a Tropic hormone so this is again released from the anterior lobe of the pituitary gland and it is going to act on the adrenal gland it's going to turn the adrenal gland on and tell it to secrete some hormones so um that's exactly what it does the adrenal gland when act acts on the adrenal gland the hormones that are secreted include this hormone called cortisol a hormone called aldosterone and some sex hormones so in women estrogen and progesterone in men testosterone so um all of these hormones that are released there's others that are released from the adrenaline but in response to act these three are released and um this happens when stress levels in the body increase and these are low levels of like chronic ongoing kinds of stress okay and also there's a daily Rhythm to the release of these hormones where the release is is highest right before we wake up in the morning and lowest right before we go to sleep at night so there is a daily normal fluctuation kind of like a padian rhythm of release of these adrenal hormones we only get thrown off with these stress hormones coming from the adrenal gland when we are living under chronic low levels of stress and when our body is getting that message we are releasing these hormones on an ongoing basis and that can that can kind of mess up our daily rhythm of it and then um that would extend into like disrupted sleep and other results of too much of these hormones blood pressure could be disrupted weight maintenance could be disrupted um okay great um last are these ganat tropins ganat tropins just like the name implies come from the gonads gonads being ovaries and testies they are Tropic hormones so their name tells you exactly what they are tropins there are two of them there's FSH which is follicle stimulating hormone both men and women produce this and lutenizing hormone or LH okay so FSH in men um causes certain cells in the testes to secrete testosterone which then stimulates cells in the testes to make spin so this is a Tropic hormone right it is acting on cells in the testes and telling them to create testosterone all right which is another hormone right which then goes out and acts on cells and tells them they're the target cells of testosterone some of them are cells in the testes which makes them so that's the pathway FSA turns on cells in the testes to tells it to make testosterone testosterone acts in several ways one of which is to tell other cells in the testes to start making spin in women FSH causes certain cells in the ovaries to grow and then release estrogen um so then estrogen has several functions but one is to lead to a process which produces an egg every month so follicle stimulating hormone glutening hormone again is a Tropic hormone um in men we'll start with men LH stimulates these other cells in the testes again to produce testosterone so both in men both FSH and LH work on two different kinds of cells in the testes to secrete testosterone testosterone has several functions one is to to act on other cells different cells in the jesses to make start producing or continue producing Sprint in women LH or lutenizing hormone has several different functions um but basically it works with and we're going to get into this in detail at the very end of the semester so I'm giving you the basic outline right here LH and F FSH together um stimulate eggs in the ovaries to mature um and then LH is the hormone that stimulates ovulation a month ovulation being the release of one egg hopefully I mean usually one egg um per month from okay that that's all I have for now and that should round out our lecture for week one here again is a you know a way in which you can kind of review the concepts that I just went over um and I will see you next week for more on the endocrine system okay I hope this was helpful and you guys email me any questions that you have and I can create a video addressing any of those questions okay