okay we're moving on to the posterior pituitary and I'll warn you that I will ask what gland produces ADH and if you're asked what gland produces or synthesizes ADH it is the hypothalamus remember antidiuretic hormone and oxytocin are produced by the hypothalamus transported to the posterior pituitary and then secreted into the bloodstream okay all right so ADH or antidiuretic hormone the name suggests something anti diuretic so diuresis is the production of urine so a diuretic causes the production of urine this is anti-diuretic so it doesn't cause the production of more urine it causes the production of a lesser end so it decreases urine production and that's one of its functions so for this one um you're going to want to focus pretty heavily on ADH there's certain hormones that you know quote unquote are more important than others because we either get to them multiple times this semester so you might as well learn them really well now so you don't have to relearn them later so that's one reason and that's the reason why this one I want you to focus on pretty heavily because we're going to learn about it again in two other contexts one is its effect on the cardiovascular system blood vessels and then also how it affects the kidneys so when we get to the cardiovascular system in the urinary system we're going to review this hormone again so if you put the effort in now and you know as much as you can about this hormone that's you know one less thing you got to work on later in the semester okay so this one we're going to take a little bit of a step back and look at what might stimulate the production of this hormone so your hypothalamus one function of it is to monitor how hydrated you are we call that osmolarity so osmolarity is a measure of not water concentration but solutes so basically in a solution this is a little bit of chemistry so hold on here um a solution is either water or something else and the something else are called solutes and if you have a high solute concentration uh we call that a high osmolarity and one reason why your body might have a high solute concentration is because it has a low water concentration so I I like to think of a glass of salt water all right if you if you're a glass of salt water and you remove water the concentration of salt will go up all right so that so the removal of water causes a high osmolarity so when you are dehydrated your blood a lot of your other uh tissues are gonna have a high osmolarity okay when that occurs your hypothalamus detects that so your hypothalamus detects that you're dehydrated it will produce more of this hormone ADH it'll go to the posterior pituitary it'll then go into the bloodstream and go to its three main targets so think about it when you're dehydrated what do you want your kidneys to do well you want your kidneys to decrease how much urine they produce right because the more urine you produce the more water you lose so you decrease diuresis AKA you're an anti-diuretic you're going to decrease perspiration so you're you're going to want to inhibit these sweat glands right because sweating is going to make you even more dehydrated and then the third one has to do with your blood pressure when you lose fluid you lose some of that fluid from your bloodstream so your bloodstream loses some of the volume it has and when your blood volume goes down your blood pressure goes down so one sign of severe dehydration is a drop a severe drop in blood pressure so one way your body can help raise blood pressure is what we call vasoconstriction so it takes blood vessels in particular the little arteries and we're going to learn more about these obviously when we get to cardiovascular system but your little arteries can affect your blood pressure so what you do is you constrict all these little arteries throughout the body and that'll raise your blood pressure okay so these three actions are all in response to when your body is either severely dehydrated or it could help if your blood pressure drops for other reasons but the key here is to know that when you're dehydrated you got to stop producing so much urine you got to stop sweating and then you got to keep that blood pressure up okay there is a syndrome of you know overproduction of ADH and again if you over produce ADH improperly right you're going to retain too much water uh the hyposecretion that's the one I want you to remember is known as diabetes insipidus now this is not the diabetes we hear a lot of that's called diabetes mellitus but the word diabetes has to do with overproduction of urine in this case the overproduction of urine occurs because you're not producing enough ADH okay so you produce large amounts of of urine and you often will become very thirsty and dehydrated okay this is just another slide I couldn't figure out which slide I liked better so I kind of just kept both slides in this PowerPoint so it kind of reminds us that you know when we're dehydrated we're going to want to produce more ADH so this is you know where it's produced up here in the hypothalamus it's transported down to the posterior pituitary and then it is secreted and goes to those three main targets all right the kidneys sweat glands and arterials and again we're going to revisit this one a number of times the rest of the semester so I always warn students that this is probably one of the more important hormones in this chapter all right next one same kind of path in that it's produced at the hypothalamus secreted by the posterior pituitary it's called oxytocin so oxytocin has a number of targets uh the two primary targets are the uterus in a female all right and specifically the muscle of the uterus and then mammary glands so let's look at its effect on the uterus so what oxytocin does to the uterine muscle is it stimulates contraction of that muscle and that's done during you know normal childbirth normal labor this is an example of positive feedback so what happens later on in pregnancy is the the cervix right here where the baby is going to eventually come out stretches because there's pressure put on that cervix all right so this cervix area has stretch sensors so it knows when that baby is pushing down on that cervix and that's going to go up and stimulate more production of oxytocin and then that oxytocin comes and targets the muscle and causes contraction of that uterus which starts to push that baby into that cervix more and as it pushes more you're going to get more stimulation of oxytocin and you're going to get more contractions so notice that it's positive feedback because the more contractions you get the more stretching of the cervix you get the more oxytocin you get so when a when when a woman enters labor it's supposed to get more frequent of contractions and stronger contractions from this positive feedback due to oxytocin in some cases a woman might not be progressing enough during the during labor so there's a synthetic form of oxytocin known as pitocin alright so they'll just give pitocin by IV and it does the same thing as oxytocin it stimulates that uterine muscle now after pregnancy or I'm sorry after delivery oxytocin will continue to stimulate that uterus so it helps get that uterus back down to a normal size and it also targets the breasts so the mammary glands and what it does to them is it doesn't stimulate the milk projection right that was prolactin it'll stimulate what we call letdown which is the ejection of the milk from the breast all right so students always confuse those two prolactin versus oxytocin all right make sure you know who makes the hormone all right it's the same Target but it's a different action on that Target and then this hormones also often referred to as the love hormone it kind of does some things in the brain and and allows you know individuals to have a little more uh social bonding and this is believed to be the reason why women tend to be a little better at Social bonding than males males do have a little bit of oxytocin but not as much as women uh we're not going to get into the overproduction under production uh notice here over sensitivity to emotions um I've had my wife pregnant a couple times and I'm not gonna give details but both those times there was a lot of emotions uh running around in my household uh hypo secretion again might affect breastfeeding severely low oxytocin might affect that social behavior so there is some influence in the brain that this hormone has okay uh pineal gland so we're moving on to a new gland okay we went from anterior pituitary posterior pituitary now we're on to the pineal gland and I'll remind you it's up in the brain it's part of the diencephalon specifically the epithalamus which is you know back here sticking kind of posterior from from the diencephalon and this gland produces one hormone and it's called melatonin melatonin has a lot of targets but it's mainly in the brain uh where it regulates our uh sleep and wake Cycles kind of our day and night cycling sometimes we'll refer to that as circadian rhythms so the levels of this hormone are influenced by how much light all right so during the daytime it actually inhibits the production of melatonin and then in the evening when it gets darker out we start to turn our lights off melatonin levels actually rise so the Melatonin actually plays a role in the in the Sleep portion of our sleep wake Cycles it also has some influence and sexual maturity and puberty but we'll focus mostly on that on sleep and weight cycle wake Cycles um and we can supplement their you know supplements of melatonin that some people um believe helps them sleep better some people have taken it and it hasn't worked the jury's kind of out whether it it really does the trick or or maybe it's a placebo effect but um typically something like melatonin uh won't harm you unless you really over take this supplement but you know I always advise if you can live without a supplement um you're probably better off because um sometimes even supplements have side effects that a lot of people are are not aware of overproduction might cause drowsiness under production again might contribute to insomnia and trouble sleeping okay next one thyroid gland let's see should we start a new video on the thyroid gland I think we will so we're going to stop this video here and we'll try to do a few organs a few glands in the next video