0:00 Armando Haciurungan biology and medicine videos, please make sure to subscribe, 0:05 join the four 0:06 main group for the latest videos. Please visit Facebook Armando Haciurungan. In 0:11 this video, 0:12 we are going to look at the mechanisms of red and release. And there are three 0:17 main ones. 0:19 But before we go and look into the mechanisms of red and release, let's just 0:23 understand 0:24 where it comes from, which is the kidneys. So the kidneys actually produce the 0:30 renin. 0:30 And renin is an enzyme, an important enzyme that aims to increase blood 0:36 pressure. So let's 0:38 just try to understand the structure of the kidneys, like what it's made of. 0:44 And it's 0:44 made out of the functional units called the nephron. The nephron has a front, 0:49 the bermins 0:49 capsule area. It has the proximal convoluted tubules. It has the loop of Henle, 0:55 which is 0:56 essentially a loop and then has a distal convoluted tubules, which actually 1:00 goes back up and sort 1:02 of meets with the head of the nephron. And then the collecting ducts where 1:07 urine essentially 1:09 comes comes through produced. So here, I'm drawing a blood vessel. The blood 1:15 vessel will 1:16 enter the glomerulus, the bermins capsule area, and the blood will be filtered 1:22 into the nephron. 1:24 And then the blood, the remaining plasma, will leave the blood vessel. And if 1:29 you want 1:29 to understand more about this nephron and the kidney physiology, please watch a 1:35 video 1:35 on that. But we won't really talk about that there. But we will focus on this 1:39 section here, 1:40 because this section is where we can find cells that produce renin. So let's 1:49 just zoom into 1:49 this section and understand a bit more about the structures and cells found in 1:54 this area. 1:55 So here, this area is known as the jukstah glomerular apparatus. And it 2:02 essentially consists 2:04 of the head of the nephron here. It has the bermins capsule, which is 2:08 essentially this 2:09 space within this, within the head of the nephron. And then you have the prox 2:15 imal convoluted 2:16 tubules, which are made up of more cuboidal-like cells, as you can see, whereas 2:22 the head of 2:22 the nephron, it's sort of just squamous cells, this thin cells. And as I 2:30 mentioned before, 2:32 the distal convoluted tubules of the nephron actually sort of meets back up 2:37 with the head 2:38 of the nephron. And this is important, because there are cells around this area 2:45 known as 2:46 the macular denser cells. And we will talk about these cells soon enough. And 2:51 again, 2:51 just to orientate where we are, we have blood vessels coming into the head of 2:56 the nephron. 2:58 Blood vessels known as the afferent arterial, and the afferent arterial will 3:02 bring blood 3:03 into the bermins capsule, to form the glomerulus. And then this blood, the 3:09 plasma will be filtrated 3:12 into the nephron. And then the remaining plasma will just leave out through the 3:17 efferent arterial. 3:19 Now there are a group of cells located around here where the afferent arterial 3:27 comes in 3:28 around this area, and where the distal convoluted tubules sort of meets the 3:32 head of the nephron. 3:34 There are a group of cells here known as the juxtaglomerular cells. And it is 3:39 these cells, 3:40 the juxtaglomerular cells that produce the enzyme renin. When renin is produced 3:46 , renin 3:46 does not get filtrated into the nephron, but it just passes through all these 3:51 blood vessels 3:51 stuff, and will leave through the efferent arterial. And then renin will just 3:57 enter systemic circulation. 4:00 So there are three ways renin is released. First way is through what's known as 4:08 the baroreceptor 4:10 mechanism. The baroreceptors are a group of receptors that detect changes in 4:17 pressure. 4:18 So when there is decreased pressure in the afferent arterial, this will promote 4:25 renin 4:25 release. Okay, just before we continue on, why would this be? Well, the goal of 4:33 renin 4:34 is to increase blood pressure. So if you have a decreased in pressure, this 4:40 tells the juxtaglomerular 4:41 cells that hang on, we have decreased in blood pressure. Let us make renin to 4:47 increase blood 4:48 pressure. So that is the first mechanism of how renin is released through the 4:53 baroreceptor 4:54 mechanism. The second mechanism is simple. It's the sympathetic nerve mechanism 5:00 . And 5:00 this is essentially the nerve, the sympathetic nerve fibers, which are beta one 5:05 adrenid nerves 5:07 that stimulate renin release. Because during periods of sympathetic activity, 5:13 fight to 5:13 flight, you have, you usually have an increase in blood pressure. And so you 5:18 have renin release. 5:21 The third mechanism, which is probably one of the most important is the macular 5:27 denser 5:28 mechanism. And macular densers are sort of chemo receptors that detect how much 5:36 sodium 5:37 chloride are passing through the distal convoluted tubules. And so if there's a 5:44 decrease in sodium 5:45 chloride in the distal convoluted tubules, these macular denser cells will 5:50 stimulate 5:50 the juxtaglomerular cells to produce renin. But it's also the same case if 5:56 there's an 5:56 increase in sodium chloride. If there's an increase in sodium chloride, this 6:00 will tell 6:02 the juxtaglomerular cells to stop producing renin. And similarly with the bar 6:06 oreceptor. 6:08 Anyway, let's look, let's talk a bit more about renin and what it does, just 6:12 briefly. 6:13 So as we mentioned, renin aims to increase blood pressure. How? Well, there's 6:19 this substance, 6:21 well, no substance. There's this substrate produced by the liver known as ang 6:26 iotensinogen. 6:27 And this just floats around until it meets renin in the bloodstream. Renin is 6:33 an enzyme, 6:34 which will convert angiotensinogen to angiotensin 1. Angiotensin 1 does a few 6:39 things in the body, 6:40 but it's not very important in this case. However, when angiotensin 1 travels 6:47 to the 6:48 bloodstream and goes towards the lungs, for example, it will come across an 6:54 enzyme in 6:55 the lungs, in the alveoli of the lungs called angiotensin converting enzyme, or 7:01 ACE for 7:02 short. ACE will convert angiotensin 1 to angiotensin 2. Angiotensin 2 is 7:13 extremely potent hormone 7:17 that increases blood pressure, so it will do many things that will increase 7:22 blood pressure. 7:23 And I'm not going to talk about it in this video, but hope you enjoyed this 7:27 video on 7:28 the mechanisms of renin release. Thank you for watching. Bye.
