0:00 Armando Houserungan, biology and medicine videos, please make sure to subscribe 0:06 , join 0:06 the four main group for the latest videos, please visit Facebook Armando Houser 0:10 ungan. 0:10 In this video, we're going to look at hormones produced by the kidneys 0:14 essentially, so we're 0:16 looking at renal hormones, and there are three main hormones. 0:20 So before we start, let's just look at the anatomy. 0:24 So here we have the two kidneys, the left kidneys slightly higher than the 0:28 right. 0:29 Here we have the inferior vena cava, which sort of where the renal veins drain 0:37 into, 0:38 and then you have the descending aorta, the abdominal aorta, which supplies the 0:43 kidneys 0:44 with blood. 0:46 And then coming off the kidneys, you have the ureter, where urine will then be 0:51 stored 0:51 in the urinary bladder here. 0:53 Now above the kidneys, you have glands known as adrenal glands, and above the 0:57 right kidney, 0:59 you have the liver, and above the liver essentially, and above everything else, 1:02 you have the diaphragm, 1:04 which separates the thoracic cavity with the abdominal cavity. 1:08 So that was a quick brief look at some general structures. 1:14 And here I'm drawing just a blood vessel, which will represent the blood, 1:19 essentially 1:20 what we find in the blood. 1:22 And here I'm drawing the bone. 1:24 Now why I'm drawing the bone, because it will relate to one of the renal 1:29 hormones. 1:30 Within the bone, actually looking at the bone marrow, we have stem cells which 1:35 can give 1:36 rise to red blood cells through a process. 1:39 Now during periods of hypoxia, or where we have a decrease in partial pressure 1:45 of oxygen, 1:46 the kidneys will begin producing erythropoietin. 1:50 So a decrease in oxygen essentially will stimulate the kidneys to produce ery 1:54 thropoietin. 1:55 erythropoietin is a hormone which stimulates erythropoasis, which is 2:00 essentially the production 2:01 of red blood cells. 2:02 So it will stimulate the stem cells to produce red blood cells. 2:06 And so with a lot of red blood cells being produced, this will increase oxygen 2:10 carrying 2:11 capacity. 2:12 So thereby trying to replenish the diminished oxygen we have in our body. 2:19 So that was one hormone. 2:20 The second hormone is produced when we have a decrease in blood pressure. 2:25 When there's a decrease in blood pressure, a few signals will tell the kidneys 2:29 to produce 2:30 an enzyme known as renin. 2:33 So renin is not actually a hormone, but it will relate to some hormones. 2:38 So renin is an enzyme which will convert a molecule called angiotensinogen, 2:44 which is 2:44 normally produced by the liver and angiotensinogen just circulates in the blood 2:51 . 2:51 Well renin will convert angiotensinogen to angiotensin-1. 2:56 Angiotensin-1 is not very potent, but when angiotensin-1 travels to the lungs, 3:05 it will 3:06 encounter an enzyme called ACE, angiotensin-converting enzyme. 3:11 So ACE will convert angiotensin-1 to angiotensin-2. 3:16 Angiotensin-2 is a very potent hormone which increases blood pressure through 3:23 several mechanisms. 3:25 So this is the other important hormone. 3:30 Now the third hormone that is produced or actually activated by the kidneys 3:38 relates to calcium 3:40 and phosphate levels in the blood. 3:43 I'm introducing another endocrine gland here known as the parathyroid gland 3:47 because it will 3:48 relate to this renal hormone I'm talking about. 3:53 So the parathyroid glands are endocrine glands, we have four of them, and they 3:57 're located 3:58 on the dorsal side, the back of our thyroid gland which is in the throat area. 4:06 So in periods where we have a decrease in plasma calcium, so when we have like 4:12 low calcium 4:13 levels in the blood, the parathyroid gland will produce parathyroid hormone. 4:20 So parathyroid hormone will do something. 4:24 So let's just pause there and introduce the liver. 4:33 So let's just introduce the liver now which actually produces a pre-hormone 4:39 called calcidiol. 4:40 Now calcidiol actually originates from the skin but then it travels to the 4:46 liver where 4:47 it actually becomes calcidiol. 4:49 And calcidiol then travels from the liver via blood to the kidneys where the 4:55 kidneys will 4:56 convert calcidiol to the active form calcidiol, and parathyroid hormone 5:02 actually stimulates 5:04 this process of the conversion from calcidiol to calcidiol. 5:09 So what is calcidiol? 5:11 Well calcidiol is actually the active form of vitamin D. So calcidiol has many 5:18 effects 5:19 in the body, it targets a few things, for example it targets the intestine, the 5:26 bone 5:27 as well as the immune system. 5:30 In the intestine calcidiol will increase the absorption of calcium and 5:35 phosphate. 5:36 In the bone it will increase bone reabsorption, resorption actually and 5:42 therefore increasing 5:43 calcium and phosphate levels. 5:46 Calcidiol also affects the immune system and induces immune cell 5:51 differentiation. 5:52 But calcidiol actually also affects the kidneys itself by increasing the re 5:58 absorption of calcium 6:00 from the nephrons. 6:03 So as you can see the main goal of calcidiol is to increase essentially calcium 6:09 levels in 6:11 the blood and this is supported by parathyroid hormone. 6:20 So I hope that made sense. 6:21 So those are the three important hormones, actually two important hormones and 6:25 one enzyme 6:26 which is erythropoietin, renin and calcidiol. 6:30 Hope you enjoyed this video, thanks for watching.
