okay so we're going to touch on chapter 26 the urinary system this first video is really gonna focus a lot initially on the anatomy of the renal system as we usually do for most of the systems let's find the part to name the parts and then we'll look at how they work now the functions of the urinary system are going to be to be involved in the removal of these waste products from our metabolic activity within our bodies so as our bodies are producing energy they're going to generate waste products and we need to get rid of them the kidneys are going to take these waste products and be able to get rid of them from our bodies and they do this by producing a substance that we call urine the different organs that are going to be a components of the urinary system is going to be of course at the kidneys we have two of them the urinary tract which we will identify in the lab is going to consist of the tubes that we call the ureters the ureters are going to allow the urine that's produced to pass from the kidneys to the empty chamber that we call the urinary bladder and then this year and it's going to exit from the body via the urethra we did look at these structures in our cat dissection the process by which we eliminate this urine from our bodies is called urination or micturition now the primary functions that we see within the urinary system can be described or defined as one excretion this is going to be the process by which the metabolic wastes are removed from our body fluid so for instance our blood in the elimination is referring to the ridding of the waste from our body so with the urination now the kidneys in the urinary system are also very highly involved in maintaining homeostasis within our body so this is going to be particularly involved with maintaining the volume of our blood and closely linked to that is our the molarity or the concentration of solute solutes within our blood so with the maintaining homeostasis this is going to touch on regulating our blood volume which is directly linked with regulating our blood pressure we do this by monitoring and adjusting the volume of fluid or water that we have in our blood so if we're gonna regulate what is lost in urine and what is held back or retained within our body the kidney is going to release two different hormones that help with this one is a wreath repeatin that we touched on with the blood chapter involved in the production of blood cells andreen in which we've touched on throughout a couple chapters which is going to be involved with the renin-angiotensin-aldosterone system and of course tightly linked with the changing or adjusting the volume of water or fluids within our fluids such as our blood it's going to be the regulation of various ions and solutes within our blood so the sodium is one we can concentrate on particularly and if we go back to our previous chapters and we went back in 168 and we talked about it with the bone chapter and I think we talked about it with the digestive system in multiple different perspectives we look at the hormone calcitriol that is produced by the kidneys that's going to help us absorb the calcium into our small intestine this is an ion it's going to affect your osmolality and also highly involved with maintaining the pH of our blood so this is because the urinary system is going to regulate the passage or retention of hydrogen ions and bicarbonate ions that are going to either be retained from the urine or excreted in the urine so drawing back to the respiratory chapter that we just finished if we recall that we pointed out how much regulating the pH of blood and / the partial pressure of carbon dioxide was a function of the respiratory system we can see here that the urinary system is also highly involved so where we have to maintain our blood pH to avoid alkalosis analysis acidosis we see that the urinary system in the respiratory system are going to be highly involved in this the urinary system is going to make sure that we don't lose necessary nutrients through urine loss so as we look at how the nephrons and the kidney function we're going to look at how it reabsorbs necessary nutrients such as glucose and all so we get rid of byproducts of metabolism that can potentially be harmful to us such as urea that's going to be involved in the processing of our amino acids the urinary system can or the kidney can be involved in helping out that the liver if need be it can function with detoxification or even the de-animate deamination of amino acids so our liver can produce the amino acids that we need when we're not taking them in through dietary methods and the kidney can assist also now our kidneys are found and the posterior side of our body just maybe at the most inferior portion of our ribcage on either side of our spinal column we looked at these in the in the cat of course the animals are four-legged so they are door so rather than posterior now the left kidney is raised up a little bit higher than the right any thoughts why we've got our liver there and that's quite a large organ and we saw in people well we didn't see in people but in a cat the adrenal gland was separated from the kidney up close but separate however in people the adrenal gland sits right on top of that kidney like a little little hat little Santa hat the kidneys are retro peritoneal so when we looked at our cats when we got to the kidneys there was a pretty thick layer of connective connective tissue that we had to cut through and then of course it had quite a large amount of adipose tissue surrounding it as well got to protect those kidneys now the kidney has various layers around it right on the kidney is a fibrous capsule it's pretty tough you may or may not have picked it off of your kidney from your cat dissection we were kind of shut down before we got that far then as mentioned there's a lot of adipose tissue peri nephritic fat fat around the kidney going to protect it and then a renal fashio so another layer of a connective tissue this is going to help hold that kidney into place interestingly enough the adult kidneys although we have two of them they're not that large it's about $0.10 meters they have a structure the hilum one of those indentation areas where we find the vessels entering and exiting from the organ as a hilum is a term that we see associated with several organs and has similar function the capsule is going to surround this kidney it'll cover a sinus a renal sinus where we find the structures entering and exiting from the kidney it's going to function really just to stabilize all these vessels now let's look at the internal area of the kidney let's go back to this picture this is helpful the outer portion and this we touched on in our cats the organs is the cortex so this would be referred to as the renal cortex renal referring to the kidneys because this is not the only organ in our body that has a cortex like your brain has a cerebral cortex so hint hint on an exam such as a lab practical make sure that you identify it as specifically what type of cortex it is deep to the cortex we have the medulla within the medulla we see these seashell shaped structures these are the pyramids and in between each of these pyramids we see the columns the renal columns and the if you take the columns and the pyramid this is in the cortex surrounding it if I go all the way up to the cortex this is going to be a lobe with in the kidney now this structures we looked at and this is actual kidney here you're going to this is where you're in production is going to take place now there's a little bit of a granular appearance to the cortex that's a little bit hard to see even on our cat kidney because of the structure of the components in it and then the pyramids tend to appear maybe a little more linear because of the components that are found in there the urine is going to be produced and the nephrons within this area and then it's going to collect into this opening area here and then travel down through the ureter to the urinary bladder so look it's look at some more of this Anatomy if we zoom in close to our pyramids we see that as the urine is being produced and coming down through these pyramids through various dogs here it's going to enter into a small cup like area this is called the minor calyx the minor calyx is going to empty into a larger area called the major calyx and then urine will empty from the major kayla sees in to the renal pelvis which is actually when we are looking at a kidney if you really cut open your catkin and you will be able to see it is almost like an an opening area that you could put your probe in the supply of the circulation to the kidneys is about 25% of cardiac output so it's significant the oxygenated blood is going to arrive to the kidneys via the renal artery we found those under cats there are several branches of the arteries and then reversely the Venice system I don't want to focus too much on the arteries that branch to travel between the lobes and then our the pyramids I do want to focus on the art arteries and veins or the circulatory system or the vasculature specifically with the function so here we have the renal artery taking the oxygenated blood will travel between the lobes enter low bar low bar artery then into the arcuate arteries and then we'll spend a lot of time focusing on the functional activity within this glomeruli up here the deoxygenated blood is going to exit through the Venice system of the interloper veins and then out of the renal vein what I really want to focus on is your blood into and out of the kidney and then at the functional layer here this is what I want to focus on the kidney is going to be innervated by the sympathetic nervous system currently there's not very sympathetic innervation identified so remember this is sympathetic is a part of our autonomic nervous system so if you are being chased by a bear and your autonomic nervous system is kicking in with the sympathetic division a primary function of your body at that time is not to produce a lot of urine so we'll look at how that functions later the functional unit within the kidneys is called the nephron and the nephron is going to consist of various components we're gonna spend a lot of time looking at the nephrons its anatomy and its function in fact we're going to repeat this in lab almost exactly the nephron are the the nephron is going to consist of the renal corpuscle and the renal tubules components are going to be connected to a collecting system the renal corpuscle will see is comprised of the capsule that we can call either the glomerular capsule or the Bowman's capsule Bowman's capital capsule is all people language so you'll hear me say it newer terms glomerular capsule within the glomerular capsule you'll find the arteries call or the capillaries called the glomerulus so we go in here we see this is the glomerulus and glomerulus means the ball of yarn and so that's based on what it looks like it's all balled up this is just referring to the structures we looked at and the glomerulus is important to point out there is let me go to the next one it's not pointed out both here if we look at the glomerulus we have an arteriole leading into the glomerulus the afferent arteriole we enter into this ball of yarn glomerulus and we exit it's an afferent it's still an arteriole efferent arteriole then let's go back make sure we got everything important on here okay if we want to look at this capsule that's part of the glomerulus are the renal corpuscle it has two layers you've got your our outer a layer that's the epithelial tissue and the visceral layer that's going to cover the this glomerulus the space in between is called the capsular space the capillaries of the glomerulus are fenestrated fenestration means windows or holes so the endothelial cells of these capillaries have pores between them another type of cell we find within this capsule is going to be called mesangial cells and these are we find these in more than one area so the ones here are called the intra lemare euler mesangial cells and they are going to be found amongst the lamellar capillaries they're gonna have several functionings they're going to not just be supportive but they're going to be involved in the filtration and the phagocytosis occurring here as well as regulating the diameter of these capillaries we also see surrounding the glomerular capillaries are specific cells we call pata sites and these are unique because they have processes so things that stick out foot processes that are going to wrap around these glomerular capillaries and there's spaces between these processes that form slits that we call filtration slits so we can see the foot processes better on this picture when you see the extension out