 Today we're going to be discussing the anatomy that's associated with the urinary system. The urinary system is responsible for taking the blood and filtering the blood to create urine so that way the body can get rid of all the excess that we don't need any water soluble excess we don't need while retaining all the things that your body does need to continue to function properly with homeostasis. So in looking at the urinary system what I've created for you is this flow chart that diagrams the anatomy. We have the blood coming into the kidney and traveling all the way through to the nephron. The nephron is in black. The nephron is where we filter the blood to create what's known as filtrate. Filtrate is a fluid that is not finalized. It is something that we still need to adjust. There are things in there that we want to save versus things that we want to add to it so that we can get rid of it as waste. The waste is shown in blue that's urine and you can see it's flow out in the anatomy that it passes through on its way out. So what I wanted to do is I wanted to do an overview of each piece and discuss what happens in each piece so that way we can put this whole thing together and not only will you understand the physiology behind it but the anatomy as well. Okay so let's get started with the blood flow. We can see our starting point here is the heart. We've already done the circulatory system so you know that once the blood leaves the heart it travels through the aorta all the way descending through the diaphragm to pass into the abdominal cavity. Once it does the blood will travel into the renal artery. Okay the renal artery is the large vessel that leads into the kidney, right in the hillum. From there the renal artery is going to branch and you're going to see what's now known as the segmental artery. The segmental artery is going to be found in the renal pelvis area so in this large collection area you can see the renal artery segments up into the segmental artery. The segmental artery once again is going to branch and become known as the interlobar artery. The interlobar artery is located in these renal columns so you can see them in between the pyramids so it's between the lobes interlobar. Okay and then that continues on to become the arcuate artery and you can see with the arcuate artery it actually arcs over top of the pyramid hence why we have its name arcuate. Okay next is going to branch again and become what's known as either the cortical radiate arteries or the interlobular arteries. I like to remember interlobular but there is a spelling issue if you can see we already talked about the interlobar. Interlobular has an extra UL in it so it's important that you guys make sure you write that down. The way that I've remembered it is that the famous movie Ferris Bueller's Day Off Bueller was trying to get as far away from school as possible so when I look at the interlobular artery this is the one that's furthest away so the interlobar is going to be in the renal columns and the interlobular is going to be out in the renal cortex. Okay and then from there the interlobular, excuse me it becomes the afferent arterial. The afferent arterial is quite large in diameter and it's going to funnel the blood into the capillary bed so just like the rest of the circulatory system we've seen the arterial funnels the blood into the capillary. The capillary in this case is called the glomerulus and the glomerulus is this twisted capillary ball where the more that we can fold and put into the space the more exchange we're going to have or the more filtration so it's really important that we have this twisted capillary ball and so we have to make sure it's really twisted to safe space. Once the blood moves from the glomerulus it travels into the efferent arterial. The efferent arterial is quite smaller than the afferent arterial. The efferent is leading away. Most of the blood is going to be filtered at the glomerulus so there's going to be less of it traveling through the efferent arterial so less diameter for less volume. Once the blood leaves the efferent arterial it continues on through the renal cortex and what's known as peritubular capillaries. The peritubular capillaries are the capillaries that are associated with the nephron and we'll get into that in just a minute but these are the ones that are found in the actual cortex itself so in this outer portion of the kidney that's where you find the peritubular capillaries. Okay from there the blood will travel through what's known as the vasorecta. The vasorecta is a capillary bed that is attached to the peritubular capillaries but it extends down into the medulla so peritubular capillaries are up in the cortex the outer portion vasorecta is going to be deeper down in the medulla. Okay but just like all capillaries okay once the blood goes into a capillary you're going to have exchange and then the blood's going to travel back out through the venous system so once the blood travels out from the cortex it's going to go into the interlobular vein. Notice the similarity there between interlobular artery interlobular vein so these are sharing a name based on their location. Remember these are also called cortical radiate so they radiate through the cortex. From the interlobular vein we're just doing our flow chart in reverse. Argue at vein arcs back over top of that pyramid then into the interlobar vein and going through that renal column then back out through the renal vein. Okay from the renal vein it's going to travel through that inferior vena cava back up to the heart.