 Hello everyone. Am I what able to you? Yes. Tell me. Yes. What are we discussing in the previous class? Sir, the types of nephrons. We finished. We finished with types of nephrons. Okay. Just a minute. We are going to discuss types of nephrons. We have discussed that or we are about to discuss that. So we finished discussing. Yes. Let's see. Types of nephron. We have done. Okay. Have we done this point? A very important point. Glomerulus, Bowman's capsule, PCT and DCT is situated in the cortex. Enlays loop is situated in the collective. Enlays loop and collective duct is situated in the medulla part. Yes or no? I think we are done with that. Yes. Sir, are you there now? Yes. Let's see everyone. The next thing is mechanism of urine formation. What? Mechanism of urine formation. Yes or no? Am I what able? Clearly? Yes sir. Yes. Let's see. First is glomerular filtration. Second is tubular reabsorption and third is tubular secretion. Let's see. Glomerular filtration, tubular reabsorption and tubular secretion. There are three. Agreed everyone? Agreed everyone? Let's see. Now, you people have two kinds of pressure that is there. One is hydrostatic pressure. Another is colloid osmotic pressure. Hydrostatic pressure is due to fluid and colloid osmotic pressure is due to dissolved protein. Yes or no? Colloid osmotic pressure is due to dissolved protein. Yes or no? Agreed? See how that pressure is going to work. Like see this is a pipe and if I will talk about hydrostatic pressure, if a pipe is going to burst or ruptured, what happens? The water moves outside, no? Yes sir. Yes or no? That means the hydrostatic pressure on this wall is towards outer side. Yes or no? Yes sir. And on this wall it will be towards means from fluid towards wall. It is acting. Yes or no? Everyone? Yes sir. And let's see. Proteins are colloidal in nature. What? Proteins are colloidal in nature. Let's see. What will happen in case of protein? In case of protein, what will happen? Protein will try to bring the fluid towards itself. Yes or no? Will try to bring the fluid towards itself. Agreed? Means protein having capacity of holding the fluid. Agreed? Yes sir. Protein having capacity of holding the fluid. Means if something is pulling the fluid on this direction, so colloid osmotic pressure will be there from the wall towards inside of fluid. Yes or no? This is the direction. This is the direction. Everyone agreed? Agreed? Yes sir. Now let's see. Now let's see. I will talk about glomerular filtration. This is your glomerulus. This is your Bowman's capsule. See this is the cross section of this membrane and this is known as filtration membrane. This is known as filtration membrane. Agreed? Now let's see. What is there towards inside? Let's see. From this side, a deep blue color membrane is there. And from this side, the black color membrane is going on. Agreed? Yes sir. See. This blue color cell is representing this blue membrane of Bowman's capsule. Sorry, glomerulus. And this black one is representing this membrane of Bowman's capsule. Yes or no? You see. This is the endothelium of glomerular blood vessels. Yes or no? Endothelium. That is the epithelial tissue. Yes or no? Yes sir. Below that, its basement membrane is going to be there. Below this, its basement membrane is going to be there. Basement membrane of which layer? Every epithelial tissue having its own basement membrane. Yes sir. The gray basement membrane is going to belong to these endothelial cells. Yes or no? Agreed? Do you people know this thing? Yes sir. Just below the epithelium, basement membrane will be there. This gray one is going to belong to which layer? This deep blue. That is the endothelium of glomerular blood vessels. Agreed? Yes sir. Agreed? What is this gray one? What is this gray one? Basement membrane of endothelium. Yes. Now what is this deep blue? This is the basement membrane of this layer. Yes or no? Because this side lumen is there. So it will be below this only. So these are known as podocytes. What? These are known as podocytes. They are having put processes which is going to bind to the blood vessel. Yes or no? You see. Modified scoma epithelial cells. Agreed everyone? Yes. Let's see. They are the podocytes. What are they? Podocytes. So what is there? Endothelium of glomerulus. This side is endothelium of glomerulus. Then basement membrane of glomerulus, endothelium, then basement membrane of podocytes, then podocytes. These layers are there. So actually endothelial cells, the basement membrane and podocytes are there. Across which filtration is going to take place. Yes or no? Across which filtration is going to take place. This side blood is there and here filtrate will be formed. Yes or no? Yes. Agreed everyone? Now let's see. Let's see. There are small pores present towards the endothelial layer. That is known as fenestra. What? Fenestra. And this is known as podocytes. What? This is known as slit pore. What? Which kind of pore? The slit pore. Agreed everyone? Yes. Agreed everyone? This is known as the slit pore. Let's see here. Let's see here. What I want to tell you all? This is fenestra. This is slit pore. This is endothelial cells. This is podocytes. What is there in between? Basement membrane. These are the layers across which it is going to be filtered. Agreed. Only this area is magnified over here. Yes or no? Yes or no? Now one thing. Even Bowman's capsule has two walls. One is perietal. That is the outer wall. Outer wall and one is visceral. That is the inner wall. So which wall is, which wall of Bowman's capsule is lined by podocytes? Is it perietal or visceral? Is it perietal or visceral? Which wall of Bowman's capsule is going to be lined by podocytes? Is it perietal or visceral? Which wall? Visceral. Visceral. Okay. So podocytes lines the, lines the visceral wall of Bowman's capsule. Agreed? Okay. You people can draw this one. After that I will discuss later on. Done here. Have you understood this thing? The filtration membrane? Yes, just a minute. Yes. Copy it. Done, sir. Done here. Now let's see. Just a minute. No issues. Done, sir. Done, everyone. Let's see. Let's sit here. Now, what we are up to here, let's see. There are two kinds of pressure inside the Bowman's capsule. And two kinds of pressure inside the glomerulus. The resultant of that pressure will be known as net filtration pressure or effective filtration pressure. Under that only, under that only, the filtration is going to be done. Let's see. This is the hydrostatic pressure inside the glomerulus. What do you think? In which direction it should work? From the fluid towards the wall? In this direction? Yes or no? Hydrostatic pressure? Yes. Agreed? And colloid osmotic pressure over here. From the wall towards the fluid. Agreed? Agreed? Now, this is BH. Hydrostatic pressure inside the Bowman's capsule. Let's see. Hydrostatic pressure from the fluid towards the wall? In this direction? Yes or no? Hydrostatic pressure inside the Bowman's capsule? And this is the colloid osmotic pressure inside the Bowman's capsule? Means from the wall towards the fluid in this direction? Yes or no? In this direction? Agreed? Do you people agree with all these directions? Yes, sir. Everyone? Tell me dear. Everyone, do you people agree with this? Yes, sir. Now, important thing. Let's see what I want to tell you all. Over here, a very significant fact. This is known as ultrafiltration because filtration is done so finely that everything gets filtered except protein. Protein do not come over here. So, for what reason colloid osmotic pressure is there? What is the reason behind colloid osmotic pressure? It is due to dissolved proteins. Agreed? It is due to dissolved proteins. Agreed? Colloid osmotic pressure. It is due to dissolved protein. No issues? No. None of the protein is coming over here. So, this would be zero, no? Yes, sir. Yes. Now, I am going to calculate net filtration pressure. It should be GH plus BCOP and BH plus GCOP. Difference of that? Yes or no? GH is 60 mm of FG. BCOP will be zero. BH is 18 mm of FG and GCOP is 32 mm of FG. Will come out to be 10 mm of FG. Yes or no? So, what is the net filtration pressure over here? 10 mm of FG. Agreed? Agreed? Everyone? Yes, sir. Yes, sir. Let's see over here. Now, see this and try to interpret it. What is the meaning of this thing? Can you interpret anything out of it? Take a minute. Please try to think. Renal filtration coefficient. It is a function of number of nephron. Till your number of nephron is not changing, it will not change. It is saying for 1 mm of FG pressure difference, 12.5 mm of filtrate will be formed per minute. For 1 mm of FG pressure difference, agreed? Agreed? What should be there? In one minute, this is the volume of filtrate that is being formed. Agreed? No issues? So, for 1 mm of FG, this is the volume. So, for 10 mm of FG, what will be the volume? Agreed? Till your kidney is normal, renal filtration coefficient or KF will not change. And it is 12.5 mm per mm of FG per minute. What is the meaning of this? For 1 mm of FG pressure difference, what is the volume of filtrate that is formed per minute? 12.5. So, for 10 mm of FG pressure difference, it should be multiplied by 10. That is multiplied by 10. 125 mm per minute. That is 180 liters per day. This is known as glomerular filtration rate. Agreed, everyone? It is the volume of filtrate formed by both the kidneys per minute. It is the volume of filtrate formed by both the kidneys per minute. That is the definition of GFR. That is the definition of GFR. You people agree with this calculation here? Yes, sir. Yes. You can write down. Everyone, GFR is a very important definition. GFR is a very important definition. Please see to it. Agreed? Agreed? Done? No. Just a minute. You people can solve this question also. You can solve this question also. It is slightly different from what we have calculated. So, I will let you know the other aspect also after seeing this. Done? Everyone? Let's sit here. What is the reason behind this? Try to think. And the next question. This question is very logical question. Proteinuria is appearance of protein in urine. Appearance of protein in urine. Agreed? Okay. You have to consider that level of protein in blood is constant. Means, colloid osmotic pressure of glomerulus is constant. It is only changing inside the Boman's capsule. You all can see this question and try to solve with this diagram only. We will discuss both of them. Sir, in the second question, will GFR increase? Yes. Of course, it will increase because let's see what happens. It was zero earlier, but now it will have some value. Some value. So, here zero will not be there. Some value will be added. So, this will increase. Yes or no? Yes or no? Everyone? Yes. Everyone? And GH having a range of 60 to 75 mmHg. Considering this length, you should see what should be the likely answer in this case. It should be 20 mmHg because practically 75 mmHg is not possible. That never happens, but it is given. It is given in other mammals also. Yes. So, what's the range of GH? 60 to 75 mmHg. Here I have taken 60 only, but it can go till this. In the second question, why won't GFR decrease? If here protein will come, some colloid osmotic pressure will be there over here. This will add up over here and that will increase what? Multiply with this. You will get an increased GFR. Everyone? You will get increased GFR. Everyone? Tell me here. Say yes or no? Yes. Let's see. Glomerular filtration rate is done now. One thing you people should be knowing. Let's see here. Renal blood flow is 1100 to 1200 ml per minute. It is for both the kidneys. So, what is the likely renal plasma flow? What is the likely value of renal plasma flow? What is the percentage of plasma in blood? What is the percentage of plasma in blood? Tell me. What is the percentage of plasma in blood? It is 55%. What? 55%. So, please take out 55% of this. Roughly it is 650. It is average value. 650 ml per minute. Yes or no? Agree everyone? Yes sir. And what do you know? What do you think? Plasma is filtered or blood is filtered? It is plasma that is filtered. Yes or no? Blood says nothing to do with it. You can say nothing to do with filtration. Agreed? Plasma is filtered. Means this much volume of plasma is coming to kidney. Out of that, this much is getting formed at filtrate. This much is getting formed in kidney. Coming to the kidney. Out of that, this much is getting formed as filtrate. So, what is the fraction of plasma that is formed as filtrate? 1 by 5 almost. Means 650 ml is coming. Out of that, what is the volume that is formed as filtrate? 125 ml. Yes or no? What is GFR? 125 ml per minute. Say yes or no? Yes sir. So, what is the fraction of plasma that is filtered as filtered over here? Tell me that. It is around 20%. No issues? So, if somebody will give you the blood volume, you can calculate the filtration fraction. Yes or no? Yes sir. You will calculate the plasma flow by taking 55% of that and then 20% of that will be filtration fraction. Yes or no? Everyone? Yes sir. Calculate the renal. Calculate the renal fraction. Please calculate. You people have understood it or not? Yes sir. So, in these cases, do we assume GFR to be 125 or will it be given as a question? See, you just take out this 20%. Around 20%. Okay. Blood volume is given. It is 55% will be plasma and 50% of plasma will be filtration fraction. Yes or no? Or 1 by 5th? Sir, will it be constant like that? No, not always. Not always. It can fluctuate a bit. Almost it is constant. Yes sir. So? Yes. So, is it 220 ml? Please calculate. Let others also calculate. It will be 20% of 1100 ml I think. Yes sir. Excuse me sir. Yes. So, in these questions, so do we assume filtration fraction to be constant or GFR to be constant? Yes. See, filtration fraction is also almost 20%. If question will be asked like this, no? You have to assume that as a 20% only. Agreed? Yes. Either all the data should be given. Otherwise, because if you see, if this will increase, no? GFR can also increase. Yes or no? Yes. Everyone. Everyone. Do you people have any doubt in renal blood flow, renal plasma flow and filtration fraction? No sir. No. Let's see. See over here, dear. Selective tubular secretion, reabsorption and secretion both are there. So first, what is the meaning of reabsorption? See. Anything that is moving through this nephron will be eventually excreted out as urine. Yes or no? Means if something will remain inside the lumen of the nephron, it will be excreted out of the body. Yes or no? Yes. Yes or no? Please pay attention to my point. I am saying if something is going to remain inside the lumen of the nephron, lumen of the nephron, what it is going to do? It will excrete that substance out of the body. What if your body is going to require that substance? What should happen? It should be removed from the lumen and will be put inside the renal interstitium where peritubular capillaries and vasarecta is there that will take it away. Tell me, dear. Yes, sir. Please say yes or no quickly. Yes. I am saying over here that if something is going to remain inside the lumen, what should happen? It should be excreted out. Yes. But if that is useful for your body, then body has to take it out from the lumen and put it inside the renal interstitium so that what should happen? It will be taken away by vasarecta and you can say peritubular capillaries that is there. I have told you in earlier diagram. Yes or no? Yes. Yes. Those are blood vessels. So movement of any substance from lumen to renal interstitium is known as reabsorption. Yes or no? And movement of any substance from interstitium into the lumen is known as what? Secretion. Agreed? Yes, sir. Secretion. Agreed? Yes, sir. Everyone, secretion is movement from renal interstitium to the lumen of nephron and reabsorption is movement from the lumen to renal interstitium. Do you people agree with that? Yes, sir. Now you see the secretion and the secretion and reabsorption is going to be selective. What? It is going to happen with particular substance. But what about filtration? Everything is getting filtered now? Yes. So it is non-selective. Everything is coming. Agreed, dear? So glomerular filtration is selective or non-selective? Sir, non-selective. Non-selective. And glomerular filtration is non-selective and what about tubular secretion and reabsorption? So selective. They are happening with certain substance only. You see in PCT and DCT what are common? NSEL, bicarbonate and H2. They are common. They are reabsorbed in PCT as well as DCT. Agreed? Now what is additional in PCT? It is 70% of the nutrient. What? 70% of the nutrient. Sorry, 100% of the nutrient. 70% is something else I am going to tell you. Means if amino acid is there, glucose is there, that will be absorbed 100% in PCT only. Agreed? Yes. If nutrient is there, 100% will be absorbed inside the PCT only. Agreed? So if somebody will ask you what is the percentage of absorption of glucose inside DCT, what will you say? 100%. DCT I have asked. Will it be 0%? No, sir. Will it be 0% inside DCT because 100% is absorbed in? Yes, sir. Everyone? Yes, sir. No issues? So what is the percentage of absorption of nutrient inside PCT? 100%. Yes or no? No. From the PCT this is secretion. H plus and NS3 is secreted. Here K plus and H plus is secreted. That is conditional. If it is more, then only it will be secreted. If it is not, in that much quantity it will not be secreted. Yes or no? From the descending limb, H2O will be reabsorbed. From the ascending limb, NSCl will be reabsorbed. From the collecting duct, you see URIA is reabsorbed. And then again secreted inside the ascending limb of Henry's loop. And here water is reabsorbed. I have told you the reason because of presence of a corporeal on collecting duct. Yes or no? Everyone? Yes, sir. Yes. So this is there. You all can note it down. First understand the meaning of secretion and absorption. Then you will get to know the things. You people are getting things, no? End out in that? No. My voice is clear, no? Yes, sir. Yes. I have changed the seat. You can set up that is there. That is why I am asking. Excuse me, sir. What have you written on the diagram next to H plus? Where? This one? Oh yes, sir. Interstitium. This area is interstitium. And this is interstitium. This is lumen. Yes. Done everyone? Sir, just a minute. Okay. Done? Yes, sir. Now one important concept is of three-sold, renal three-sold. Now you see. Please try to understand my point. One important thing I am saying. For say glucose that is coming over here is, let's see it is 100 gram. All will be reabsorbed. 120 gram. All will be reabsorbed. 130 gram. All will be reabsorbed. But there will be some value after at which the absorption capacity of PCT bill will be exceeded by the concentration like 180 gram. Now, it cannot absorb more than 180 gram. Yes or no? Or say PCT cannot reabsorb more than 180 gram. What will happen in that case? That glucose will appear in urine. So that is three-sold. Is that a lower limit or upper limit? Upper limit. Is that a lower limit or upper limit? Everyone? Upper limit. Upper limit. So it is the maximum concentration of any substance in plasma till which it do not appear in the urine. It is known as renal three-sold. Yes or no? At times when renal three-sold for glucose is low, in that case glucose comes in urine at lower concentration also. So can I say that glycosuria is there? Always that, tell me, glycosuria is there, always diabetes mellitus is there? No sir. Agreed? Agreed? Yes. No issues? Yes sir. Everyone? No. Low three-sold substance, urea is there, uric acid is there. Non-three-sold substance is uric acid. Now try to understand my point. Your excretory matter should be low three-sold substance or high three-sold substance? Low three-sold. Low three-sold substance only. Non-three-sold means it will come and will be excreted. No upper limit is required. Yes or no? Everyone? Yes sir. So can I say that glycosuria is there? Is it always diabetes mellitus? Is it always diabetes mellitus? It may be low renal three-sold also. It may be low renal three-sold also. Agreed? Yes sir. Agreed? Everyone? In case of low renal three-sold also, glucose will come in urine. It is not necessarily diabetes mellitus always. Yes or no? Everyone? Yes sir. So write down a statement. Glycosuria always represents diabetes mellitus. That statement will be right or wrong? Wrong sir. Wrong. Now, on DCT, aldoesteroin is going to work. It will perform reabsorption of Na plus and secretion of K plus. It will perform reabsorption of Na plus and you can say secretion of K plus. Means, if that is happening, you will ask me that sir, what is the volume? You can say concentration of Na plus that is reabsorbed. That concentration of K plus is secreted. Then also water is reabsorbed. Why? You can ask me now, if you will apply the concept of water potential over here. Can you ask me that question? Yes. I have told you earlier, Na plus having higher hydration energy, it will attract more water molecule with it with respect to K plus. Agreed? So K plus movement do not affect much the water movement, but Na plus too. Yes or no? Everyone? Yes sir. Now, changes in filtrate during movement through nephron. Sir, could you scroll up, you can copy? Yes, yes. Need not to copy this one. This I have pasted for some reference purpose. Yes. Done? Yes sir. Now, what is the changes in filtrate that is made while moving through the nephron? Agreed? Tell me dear, I am saying over here, changes in filtrate during movement through nephron. See, when I have written in Hindi a bit, do you people understand a bit? Yes sir. When water will move, it will cause change in volume as well as concentration. And when electrolyte will move, it will change the concentration only because electrolyte do not have that volume that it is going to affect the volume. Yes. Total volume of electrolyte is negligible. So let's see. Changes in filtrate during movement through nephron. Let's see here. This is Bowman's capsule. What happens? I have told you everything that is there in the plasma that comes over here. That means it is iso or smaller with plasma. In Bowman's capsule, almost similar to plasma. Yes or no? Apart from proteins. Apart from proteins. Yes or no? It is almost similar to plasma. Yes sir, it is almost similar after absorption or before absorption sir. See, in Bowman's capsule nothing had happened, only filtrate is formed. Now, on what absorption and secretion will start? Oh yes sir, got it. What happens in PCT? What happens in PCT? Try to understand my point. Now you have 1 liter of water and 100 grams of salt. Now you have 100 liter of 1000 liter of water. Sorry, I should write ML. I have told 1 liter, no. Then 100 gram of salt is there. Now you have 100 ml of water. You have 10 gram of salt that is there. Yes or no? Agreed? Yes. Here, let's see. Let's see what I want to tell you over here is if you will take 100 ml of water and 100 gram of salt and in 1000 ml of water and 100 gram of salt and 100 ml of water and 10 gram of salt. What is the concentration difference between them? I am asking for concentration difference. Similar thing happens with PCT. See, electrolyte is absorbed actively. Electrolyte is absorbed actively. Yes or no? And in the same proportion water is also absorbed. So if electrolyte is getting absorbed and water is moving passively in the same proportion, will the concentration change over here? No sir. No. So concentration in PCT will be similar to plasma only but volume will decrease because water is moving out. Yes or no? Yes sir. And that also 70 to 80 percent volume decrease will be there. Now what will be the change in descending limb of endless loop is there going to be there? In descending limb water is moving out. If water is moving out in that case volume will decrease and concentration will increase. Agreed dear? Yes sir. Everyone, what is the changes in ascending limb? See electrolyte is moving out. Electrolyte is moving out. What is moving out? Electrolyte. Electrolyte is moving out in that case what will happen? Volume will be constant, concentration will decrease because I have told movement of electrolyte is not going to affect the volume. Yes or no? Yes sir. Agreed? So changes in? Please observe again. You have to write it down also. Apply your logic right carefully. Done everyone? Could you scroll down? Yes. See in PCT in descending limb and in ascending limb. You just apply your logic and if you have any issue you can ask me. Now changes in proximal dcT. What is the change that is going to happen in proximal dcT? It is volume, concentration. Let's see what happens in proximal dcT? This part of dcT. NSCL is absorbed by the action of aldosterone. Yes or no? It is known as conditional reabsorption. What? When water scarcity condition will be there in that case aldosterone will be released and then it will be absorbed. Yes or no? So NSCL will be absorbed over here. So what will happen? If electrolyte is moving out in that case volume will remain constant and concentration will decrease. And distal dcT, what is happening? Water is moving out. So volume is decreasing, concentration is increasing. Overall volume will decrease, concentration will remain the same in the dcT. Yes or no? First concentration is decreasing then increasing means it is similar to PCT only. Agreed here? Yes sir. In collecting duct, water is moving out. I have told you people, acoporins are there and that is under, acoporins are under. The control of antidiuretic hormone. Yes. So water is moving out. So volume is decreasing, concentration is increasing. Yes or no? Two questions are there. You can find out the solutions. So could you scroll up to the proximal distal dcT? Then everyone, you can solve these two questions. Solve these two questions. Why concentration of urine is four times than that of filtrate? Do people have the answer of this thing? And the second question. Are we done? Yes sir. See you. This question, do you people have answered? The answer is reabsorption taking place in many places so it is more concentrated. See, here it is 300 milliosmol per litre. Here it is 600 milliosmol per litre. Here it is 900 milliosmol per litre and here it is 1200 milliosmol per litre. So you see 300, 1200. Urine is filtrate is forming over here and urine is passing from here. So it will be four times. Everyone? Yes sir. What is the, filtrate is getting formed inside the cortex? So concentration inside the cortex is what? 300. So one important thing is countercurrent mechanism of concentration of urine. Countercurrent mechanism of concentrating the urine. Let's see. This is known as Henle's loop. This is known as Vasarecta. Henle's loop and Vasarecta. Countercurrent multiplier and countercurrent exchanger. Agreed? Countercurrent multiplier and countercurrent exchanger. Let's see over here. What happens? You have to follow a funda that is concentration inside is equals to concentration outside. Concentration inside is equals to concentration outside. Yes or no? Everyone? Yes sir. Concentration inside is equals to concentration outside. Let's see. What is the significance of this thing? Concentration inside is equals to concentration outside. Let's see over here. What I want to tell you all? Concentration outside is 300 milliosmol per liter. So it should be 300 milliosmol per liter over here. Here 600. Here 600. Here 900. Here 900. Here 1200. Here 1200. This means 300, 600, 900, 1200. Concentration is increasing as we move down. Move down along the descending limb of Henle's loop. Is it increasing or decreasing? Sir, increasing. Is it increasing or decreasing? Increasing. Tell me. It is increasing. So how many methods that do you, you can say, do you people know to increase the concentration? How many methods that are there? If you have to increase the concentration of a solution, how many methods do you people have? Either aid the solute or remove the solvent. Yes or no? Yes sir. So what is feasible in descending limb of Henle's loop? What is feasible over here? Sir, remove solvent. Remove solvent because it is only permeable for water, not for electrolyte. So you see water is moving out from the lumen into the interstitium agreed? From the lumen into the interstitium now. Water is moving up 1200, 900, 600 and 300. 1200, 900, 600 and 300 milliosmol per liter. Is the concentration increasing or decreasing? Sir, decreasing. Decreasing. How many methods that you people know to decrease the concentration here? Sir, remove the solute or add the solute. What is feasible in ascending limb of Henle's loop? Sir, remove the solute. Remove the solute. I am removing it. In the interstitium. In the interstitium. Agreed? In the interstitium. Agreed? No issues? Everyone. Everyone. Let's sit here. You will see that along the ascending limb of Henle's loop, the descending of limb of Asarekta is flowing. Yes or no? Yes or no? Along with that only. Alongside, you can say alongside ascending limb, descending limb of Vasarekta is flowing and Vasarekta is a Keplerina. So it is permeable for electrolyte as well as water. 300, 600, 900, 1200. The fluid is moving out. See one thing I am going to define over here that hydrostatic pressure inside the Vasarekta is already low. Means water is less. So I have to increase the concentration. I can take both the methods. I will add the solute over here and will remove a little bit of water. Not much because already hydrostatic pressure inside the Vasarekta is what? Low. 300, 600, 900, 1200. Concentration is increasing or decreasing? Increasing. Concentration is increasing. And how many methods that you people know for increasing the concentration? You add the solute and the solute. And Vasarekta is a Keplerina. Both can be done. Vasarekta is a Keplerina. Both can be done. Agreed? Vasarekta is a Keplerina. Both can be done. So I am adding the solute over here and I am removing the water from here. Agreed? Everyone? Yes, sir. Agreed everyone? Tell me dear. Yes, sir. Now you see. Everyone will see. The sending in the Limba Vasarekta 1200, 900, 600 and 300. Concentration is increasing or decreasing? Concentration is increasing or decreasing? Decreasing. Decreasing. Let's see. To decrease the concentration, how many methods can we apply? We can absorb the water as much as we can because already it is low and we will remove a bit of solute also. So those water that is removed from the descending Limba of endless loop, that will be transferred to ascending Limba of Vasarekta and this will go to blood flow. Yes or no? Is the water conserved over here? Is water conserved over here? Tell me. By this, water is conserved or not? Yes, sir. Yes. Now this concentration gradient is maintained by NSEL and URIA. Now you people can understand the role of URIA transporter that I have written over here and over here. Little bit of URIA that is recirculated in the interstitium is actually increasing the osmolarity of interstitium which is helping in absorption of water. Yes or no? Yes, sir. Agreed, dear? Yes, sir. The current mechanism because the direction of flow of fluid in both the Limba of Vasarekta and endless loop is opposite. Is it opposite or not? Yes, sir. Yes, sir. And it also runs in the gills of Vises and NSEL chamber of Kangaroo Rat. You people know what is Kangaroo Rat? That is there in the North American desert. Do not drink even a drop of water from the birth till death. Only surviving on the water, you can say obtained by fat metabolism or fat oxidation. So it is essential for Kangaroo Rat to you can say absorb moisture from the expired air. For that, counter current mechanism is running over there also. Yes or no? In gills of Vises also it is there. You people can write this thing. Can see your NCRT a bit because diagram inside NCRT is a bit different from here. Yes, I am sorry. But you people can easily compare and read. Done? Just a minute. Yes, especially this line, question will be asked from you. Counter current mechanism, the meaning is important. Please see to it. Try to understand the things. If you are not getting anything, please ask. Read here. Sir, could you scroll down a bit? Your exams are over? Yes? Yes, sir. You started solving the assignments? Not yet, sir. The results were, I think it got over this Monday, sir, so I will start today. Okay, no issues. Yes. Sir. Yes. Could you send like most of the assignments again? I was joined late on the WhatsApp groups. I don't have most of them. No, so I will send. Thank you, sir. Properties of urine. Properties of urine. The volume is 1 to 1.5 liters per day. Its pH is acidic. It is 4.5 to 6. Specific gravity is 1.010 to 1.025. Cosmology, I have told you. And color is a strong color because of urochrome pigment. Yes or no? And what is the amount of urea that is excreted per day? It is 25 to 30 grams, 25 grams. As for your NCRT, yes or no? What is the amount of urea that is excreted per day? You can check with your NCRT. It is 25 grams per day. 25 to 30 grams per day. Yes or no? Yes, sir. Per day it is. Now, one important thing is there. That is how your kidney function is regulated. Yes. Done, sir. Done. So, we will talk about regulation of kidney function. How your kidney function is being regulated? It is hypothalamus. It is JJ apparatus. It is heart. Hypothalamus have osmoreceptors which perceive change in osmolarity or change in osmolarity is there in hypothalamus. Getting my point. In the blood, these osmolar receptors will pick that one. Yes or no? And you know that in your hypothalamus, the center is there. Yes or no? And it will increase the urge for drinking water. You will drink the water and osmolarity will become normal again. Yes or no? Yes, sir. So, we are not secreting ADH or vasopressin. You know, vasopressin or ADH is secreted from which part? Secreted from which part? ADH or vasopressin is secreted from which part? Tell me. Posterior love of a tree. And it comes from hypothalamus only. So, secretion of ADH or vasopressin is going to be started. It will open the equiporeans. That will lead to reabsorption of water. And osmolarity again returns to normal. Yes or no? These two things are done by hypothalamus. When regulation means you can say changing things between physiological limit. Yes or no? Changing things between physiological limit. Yes, sir. Sir, could you scroll down? Done, everyone? Let's see. Diuresis. Excessive loss of fluid from the body. And hence, the hormone which is preventing it is known as anti-diabetic hormone. In absence of ADH, which disease is going to be there? Diabetes incipidus. If secretion of ADH is on the lower side, which disease is going to be there? Which disease is going to be there? It is diabetes incipidus. Let's see. If ADH is, you can say secreted in lesser amount, what will happen here? Water will be absorbed more or less? So, let's... Water will be absorbed. If it will be absorbed less, in that case, what will happen? Can you repeat? I told ADH is increasing the water absorption or decreasing it? Increasing. Increasing. So, if ADH will not be there, water absorption will increase or decrease? Increase. If it will be decreased, in that case, it will be lost in urine. So, frequent urination will be there. That condition is known as polyuria. More water will be lost. In that case, more water have to be taken in. That is known as polydipsia. Excessive thirst. In diabetes mellitus also, these two things will happen, but one is additional. That is polyphagia. Excess hunger will also be there. It is due to error in secretion or function of insulin. We will read about that in later classes. You can say in chemical control and coordination. Yes or no? Everyone? Yes or no? No. Sir. You can see. Yes. Could you just show the diabetes mellitus? Yes or no? Let's see here. So, hypothalamus is done. Now, we have to read JJ apparatus. You see. Just imagine, this is your woman's capsule. This is afferent arteriol. This is efferent arteriol. You see. This is a DCT. You agreed? Actually, the diagram of neprone that we used to teach you people, that is quite, you can say, that is arranged in a nice way. But it is not like that. The complete neprone is intermingled with each other. In that way, DCT is touching the afferent arteriol also. Yes or no? Yes sir. Where DCT is touching the smooth muscle cell of the afferent arteriol will get modified to form JG cells. Agreed? Agreed. The smooth muscle fiber of afferent arteriol, getting my point, that get modified to form which cell? JG cell. This is going to secrete renin. Which is going to secrete renin? Yes or no? Yes sir. Which is going to secrete renin? Agreed, dear? Now, the modified cells of DCT, this one. This is Mecula densa cells. What? Mecula densa cells. Agreed, dear? Yes sir. JG cells is going to secrete the renin. Mecula densa cells is going to secrete. It is not going to secrete anything. It is acting like a osmoreceptor. If filtrate is moving, it will perceive the change in the, perceive the change in the, you can say, concentration of filtrate. Agreed? Osmoreceptor. So what is JG cells? It is the modified, a smooth muscle fiber of afferent arteriol. And what is Mecula densa cell? It is the modified cell of DCT. You can observe few cells in this area also. They are midgen gel or lacy cells. They are supporting cells. Yes or no? They are supporting cells. Please draw the diagram. Done everyone? Just a minute. Done everyone? Just a second. Done sir. Done everyone? What is going to happen or actually what this renin is going to do from liver and geotensinogen is removed? From liver? You can say it is secreted rather than removed. It is there in your blood. It is inactive. Now you see BP is going to fall due to less fluid in the body. Water is not there. Everyone? Water is not there because of that what happened? BP has fallen. As BP will fall, it will start or it will stimulate. You can say that JG cells to secrete renin from kidney. Agreed? Agreed? And angiotensinogen will be converted into angiotensin one by renin. Agreed? Agreed? Yes. Agreed? Yes. Now you all will see that from the lung, A is secreted. What? A is secreted. Angiotensin one will be converted into angiotensin two by A. Angiotensin converting enzyme. Agreed? Yes. No issues? No issues by angiotensin converting enzyme. A is converted into angiotensin two. Let's see. Angiotensin two having three roles. One, it will stimulate the hypothalamus to stimulate the center so that you are going to drink more water and you will recover your blood volume. Yes or no? And then it will act on adrenal cortex. And from adrenal cortex it will make a aldosterone to secret. Agreed? And it will act on DCT. And what is the function of aldosterone that I have told you people? What is the function of aldosterone that I have told you people? Tell me. Reabsorption of NEPLUS and CL- and along with that H2 will be, will also be, will also be what? Reabsorbed. Yes. So by that also your blood volume is going to be recovered. Agreed here? Yes. Now, third thing it will do on blood vessel and bring about vasoconstriction. What? Vasoconstriction. By that also the blood pressure will increase. Agreed? Yes. So after action of angiotensin two, all three will act and it will make blood pressure to increase. Agreed? It will make blood pressure to increase. Agreed? Everyone? Yes. No issues? And if blood pressure will be increased it should, it should not, you can say increase beyond the limit. Otherwise that will also going to cause some problem. Yes or no? No. Once blood pressure will start increasing above the normal level, heart will secrete A and F at real natriuretic factor which is going to switch off the secretion of renin. Yes or no? Which is going to switch off the secretion of renin. So at real natriuretic factor is known as check mechanism of RAS. Yes or no? Yes. Renin angiotensin, aldosterone, you can say system. This is the role of renin over here. See, spelling of renin over here and in GIT, both are different here. Agreed? Yes, sir. Yes. You can see over here. Done everyone? Just a minute, sir. Are we done? So just a minute. So could you scroll up to the A and F part? Done, sir. Yes. We will be discussing the myogenic auto-regulation after the break. Yes or no? We will be meeting you people after 10 minutes. 10 to 15 minutes. Break is there? Yes. Okay, 15 minutes. No issues. Yes, sir. Yes, everyone? I am back. Let's see. You all are there? You all are there? And am I audible to you? Yes, sir. Yes. Let's see. What happens if there is abrupt increase in BP? If there is abrupt increase in BP, BP will increase. You can say suddenly what will happen? That can cause damage to the kidney. Agreed? You must be knowing this is one of the complications of increasing blood pressure. Damage to the renal blood vessel or damage to the kidney. So what happens if this will happen? In that case, as blood will rush in, in that case what will happen? Pressure will increase inside the vessel or not? Pressure will increase or not? Yes. In that case, the blood vessel will be stressed. Yes or no? Blood vessel will be stressed. Yes or no? Yes. Blood vessel will be stretched. In that case, if it will be stretched from the intercellular space, it means you can say between the, you can say space present between the cells, calcium ion will rush in inside the myogenic layer of this. Yes or no? Yes. Blood vessel do have what? Muscles in them. Yes or no? Blood vessel do have muscles in them. Agreed, dear? Yes, sir. What happens if calcium ion will rush in, muscle is going to contract? Yes or no? Yes, sir. That will lead to contraction of muscle and because of that, what will happen? Due to contraction of muscle, what will happen? The lumen will decrease in, the lumen will decrease in size and blood flow to the kidney will decrease, hence GFR will decrease. Yes or no? Means you do not see this as a functional aspect rather than you see this as protective aspect. Yes or no? Yes, sir. Ideally, what should happen? If BP is increasing, GFR should increase by simple logic. If blood pressure is increasing, GFR should increase by simple logic. But what is there? If the increased BP will be transmitted as it is in that case, what will happen? Sir, damage to the vessels? Yes. So, because of that, blood vessel is going to constrict and that will lead to decrease in GFR. Yes or no? Everyone? Yes, sir. Yes, you can write it down. Dan? Yes, sir. Myogenic auto-regulation. You people can see over here. Now, what is mixturization? It is the process of release of urine. Process of release of urine. Have you read here? What happens? It is a neural mechanism. Let's see. Which kind of epithelium is present inside the urinary bladder? It is transitionally epithelium. Yes or no? And outside it is peritonium. What? Outside it is peritonium. In between that is detrusor muscle. Yes or no? In between that is a detrusor muscle. Yes or no? Agreed here? What is the name of muscle that is present inside urinary bladder? Detrusor muscle. Detrusor muscle. In that you can see, stretch receptors are there. What? When urine will fill, the bladder will expand. Yes or no? When the urine will be filled, the bladder will expand. And from here, a stretch receptor will be activated. And from here what will happen? Nerve impulse will go to CNS. And from CNS, a sphincter signal will come. One to detrusor muscle lead to contraction of detrusor muscle and one to a sphincter lead to relaxation of a sphincter will lead to urination. Agreed here? Yes sir. Agreed everyone? You all can see. Read this one. So what is the name of this topic? Mixturition. Process of release of urine is mixturition. One question is also there. You people can solve. Solve the question as well. You all can apply simple logic to the question and it will be solved. Done everyone? Do you people agree? Yes. Do you people agree with this sequence? Compare this sequence to this diagram. You will get to know what is happening actually. Sir. Yes. Could you show the question again please? Yes. Sir what are the types of urethra you have written on the picture? Prostatic urethra, membranous urethra and penile urethra. See. This is prostatical end. This area is not prostatic. This is membranous and the urethra present inside the penises. Penile urethra. Yes or no? Everyone? Yes sir. Excuse me sir about that question. If the receptors are removed would that cause incontinence or incontinence due to something else? If receptor will be removed in that case what will happen? Signal will not go to CNS. Yes or no? Yes sir. In that case the motor signal for contraction of the truser muscle and relaxation of a sphincter muscle will not be there. In that case your nation will not take place. You read? Yes or no? But sir when the bladder reaches capacity what happens? In that case in some of the cases sphincter may fail in that case maturation will be there. Otherwise we are going to put a catheter. Pain will be there. We are going to put a catheter in that case. Through that only we will take out the urethra. Yes. Yes everyone? No. Other organs in excretion. It is lungs liver it is skin. Remove CO2 at 200 ml per minute. CO2 will be removed. All the volatile substances will be removed and some of the water will be removed. Especially in dry and cold climate. Cold climate. More in cold and dry climate less in hot and humid climate. Can you correlate? Yes sir. Yes. Liver is the largest gland of the body. It helps site of elimination of cholesterol, bile pigment, degraded steroid, hormones, toxins, etc. Skin having cooling effect of sweat gland or serotific gland, NSEL, urea, lactic acid, amino acid, glucose, etc. and sebaceous gland, sterols, hydrocarbons, wax, etc. through sebum. This is from the NCRT only and you people need to remember them because they are important as far as need is concerned. Especially that carbon dioxide path. This one. And composition of sweat is also important. Disorders of excretory system. All disorders are there. One is glomerulonephritis. Second is renal failure. What is glomerulonephritis? It is the inflammation of glomerulus. Yes or no? In that case, let's see. Inflammation will be there. In that case, size of size of fenestra will increase. What? Size of fenestra, this fenestra is there. It will increase. Normally protein do not cross this membrane. But once inflammation will be there, in that case, what will happen? Protein will pass. And protein will come into urine. That is known as what? That is known as what? Glor... Proteinuria. Due to glomerulonephritis. Proteinuria is one of the early sign of kidney failure. Yes or no? If that is happening and will not be treated, it will lead to hematuria. It is appearance of blood in urine. It is similar region. Size of slit pore and fenestra will increase. Yes or no? Fenestra people have understood now. The space between the endothelial cells. If it will increase more, it will let the protein go through it and the RBCs go through it. In that case, what will happen? Blood will be there in the urine. And here, protein will be there in the urine. Excuse me, sir. How does this glomerulonephritis lead to increase in the size of fenestra? See, inflammation is going to do that only. Inflammation is going to increase the permeability of blood vessels. Inflammation is going to increase the permeability of blood vessels. Agreed? Yes, sir. Yes. Here. Proteinuria is there, hematuria is there. Now, renal failure. Renal failure is a condition when kidney stops functioning. Kidney is not functioning. In that case, what will happen? What is the function of kidney? To filter out urea from the filter out urea from the blood. Blood. Yes or no? Let's see. Let's solve this question. Kidney failure leads to increase urea in the blood. Urea concentration in the blood. That condition is known as uremia. Yes or no? In case liver will be failed, ammonia will increase in the blood because ammonia is converted into urea in liver only. Yes or no? Ornithin cycle. Right here. How you are going to treat the renal failure? Yes. Could we just copy it now? Yes. Actually, I couldn't copy the previous one also. Could we copy both of them before moving on? Yes. Sir, could you go to the disorders part? Sir, could you show the skin again please? No, sir. If urea will take place, once it will be damaged, it will come almost in all the urination. It will be there. It will come. Sir, can glomerular and arthritis be cured if by medication? Yes. Usually these things are there. Doctor will try to find out the reason. If reason will be removed, healing will be there and some medicines are also there. Okay. It can be checked. At least progression can be checked. Yes or no? Yes, sir. Done, sir. Done everyone. Let's see what happens in hemodialysis. What you are going to do in hemodialysis? You are going to take out the blood from a convenient artery. Why artery? Because you need not to regulate the flow. Artery will push the blood on its own. What is the most common complication that is going to happen? If you will take out the blood from the artery, it can coagulate. It can coagulate. To prevent that coagulation, what we need to add? Anticargalants. That is added so that it should not clone. Now this is passed through a dialyzing unit. See, it contains fluid. It contains fluid that is having concentration same as plasma except nitrogen as waste. Okay. All the electrolytes are same except here urea is there and in this fluid urea is not there. Yes or no? In hemodializing fluid, urea is not there. What will happen? Urea will diffuse from this side to this side. Agreed? Yes. Urea will diffuse from this side to this side and from this side to this side. Noisos? Now. Now I am going to put that blood into vein. If I am putting that blood into vein like see, the patient is already ill. The patient is going to have some problem with this. If this blood will go and if some blood vessel is damaged in that case, what will happen? Lots of internal bleeding will be there. So to check that internal bleeding, what should happen? Anti-hyperine is added before the blood is put into the vein. Yes or no? And this membrane is semipermeable membrane that is cellophane membrane. Agreed? Nothing else. So this is the concept of hemodializing actually this is a much more complex unit than I have shown that you can say over here. Now is the hemodialysis is the complete cure? No, not at all. It is a palliative care only. It is only going to relax the patient for some time. The ultimate treatment is renal failure is kidney transplant. Agreed dear? Everyone? Excuse me sir. Yes? So how do they avoid air bubbles in the blood while it is going through the hemodializing unit? See for that blood is being taken directly from the, you can say blood only no? Yes sir, but it is mechanical so there is always room for error. See it is there, it is there, you are right but usually do not understand. Okay, that is taken care of. Systems are there in place. I cannot explain at this time all the systems that are there in the hemodializing unit. Later on I will tell you if you want to know. Okay, first I will see then I will let you know because the structures are very complex. The complete hemodializing unit I don't know at this point of time. Agreed? Yes sir. Yes, I will let you know later on. Yeah, got it sir. Machine is there, I have not seen the machine from inside. I have seen the process of hemodializing dialysis. Connections are made, how connections are made that I know. Done everyone? Just a minute sir. Excuse me sir. Yes, theoretically we could hemodialize a patient for their entire life, right? Yes, but actually lots of complications are there. You cannot do it for much longer period. So what is the most basic complication that can happen? Lots of things are lost. Proteins are lost and lots of things are there. And one more thing, the most basic complication is there. Like urea is removed on the daily basis. But dialysis is not done every day. So what happens? Urea keep on building in the blood. Okay, that person is not going to have much efficiency actually. Yes sir, got it. We do not do hemodialysis on daily basis, agreed? Now the kidney transplant is the ultimate cure for renal failure. Now one thing is renal calculation. Deposition of heavy salts like oxaloacetic, oxalate, etc. Oxalate is a heavy salt. Yes or no? If it will be there in the more concentration, it will cause it and will form a stony mass inside kidney. That is known as a renal calculator or kidney stone. Agreed? Agreed here? No. Seat is pathway. Phenylalanine, tyrosine, phyvedoxyphenyl, pyruvic acid, homogenetic acid and mymallolactic acid. Agreed? Let us see over here. Phenylalanine What? This is a pathway. This Phenylalanine is there. It is metabolized like this. Yes or no? Now see, this enzyme is there. Phenylalanine hydroxylase. This enzyme is converting Phenylalanine into tyrosine. Agreed? Yes. What will happen if there is a defect in the gene of this enzyme? Phenylalanine will not be metabolized to that gene. Now see in that case it will be building in the blood and it will, it will come in the urine. That is known as phenylketonuria. The name of the enzyme is correct name is hydroxylase. Yes or no? Yes. Yes or no? So, let us see homogenetic acid is also known as elkeptone. If homogenbum say to 1, 2, dioxinate. This enzyme is having defective gene. In that case, what will happen? This will not be metabolized and will be building in the blood. That will lead to L-captoneuria. Yes or no? Yes. Agreed? Write it down. You are going to read this in genetics also Read everyone. Just a minute sir. Done. So just a minute sir. Okay. Done sir. Done everyone? Done. So just a minute. Done sir. Now see pyuria. Py means pus. Presence of pus in urine. In urine test, pus cell will be there. Static is inflammation of urinary bladder. Now, one important thing is ornithin cycle that is there. First thing it is there in the, it takes place in the hepatocytes. Means liver cells. Agreed everyone? Yes sir. It takes place in liver cells. And in which cell organelle? Mytochondria and cytoplasm. Mytochondria and cytoplasm. Agreed? See. Amino acid glutamate is there. Transamination will take place. Alpha-ketoglutric acid will be formed and one NH4 will be released. Yes or no? In reductive ammunition, I have told you people in mineral nutrition last page that alpha-ketoglutric acid is going to combine to NH4 to form glutamate. Yes or no? Yes sir. So, if glutamate will be broken, it will give these two. NH4, this is CO2. With the help of enzyme carbamyl phosphate synthase, it will form carbamyl phosphate by using two ATP inside mytochondria. So, can you see how many ATP are used inside mytochondria? Jeremy, now you see. This carbamyl phosphate is going to combine to ornithine to form citrulline. This citrulline will combine to aspartate to form arginosuccinate. Yes or no? Arginosuccinate is releasing fumarate to form arginine. And you are going to get urea after hydrolysis of arginine. Only three points are important. One, how many ATP is used in mytochondria? Another, how many ATP is used in cytoplasm? Okay. And how many total ATP is used? And after hydrolysis of what? Usually we confuse that we take ornithine. That is wrong. Ornithine is recovered after that. Arginine is going to give you urea and ornithine. Yes or no? Everyone? Yes. So, how many ATP is used inside mytochondria? How many ATP is used outside mytochondria? That is cytoplasm? Okay. And one, what all wastes are removed in the ornithine cycle? CO2 and NH4. You need not to copy all these things. Only names are important. Okay. Just name. Nothing else. So, you will send these as notes later, right? Yes. I will send it. Sir, could you show the picture again? Yes. Done. Are we done? So, what's the compound which is synthesized by arginosuccinate acid synthase? What? Arginosuccinate? See, petroleum is combining with aspartate to form arginosuccinate. In the presence of enzyme, arginosuccinate acid synthase. Agreed? Yes, sir. So, how many ATPs are used in each, sir? Two ATPs used in mytochondria and one ATP is used in cytoplasm during conversion of citrulline into arginosuccinate. Yes or no? Yes, sir. Total three ATPs used. You can solve this question. These two questions. Class. Hello. 7.30. Done, everyone. We are done with X3D system now. The next topic is locomotion and movement. Let's see. Are you people done with muscular tissue and animal tissue? Muscle contraction or not? In school, sir. You people have done animal tissue before, no? Yes, sir. You have done all these things, contraction and all? No, sir. No? Let's see. Actually, we are going to discuss the locomotion and movement chapter. Agreed? In that, one part is muscle and one part is a skeletal system. Yes or no? Actually, muscle is the part of muscular tissue, animal tissue. It should be taught over there only. Let's see. It is contractile in nature. It is misodermal in origin. What? It is contractile in nature. It is misodermal in origin. Then types of muscle tissue, skeletal muscle, smooth muscle and cardiac muscle. What all are there? Escalatal muscle, smooth muscle and cardiac muscle. Agreed here? We will discuss different types of muscle. In the subsequent, you can say slides, like, but over here, first we are going to start with skeletal muscle. Yes or no? It brings about movement at joint where joint act like a fulcrum. Yes or no? Like seizure is there. This is the fulcrum. Likewise, joint is going to act like a fulcrum. Let's see. First, we will talk about the structure of skeletal muscle. I have taken this cross section over here. What is the outermost layer? Epimysium. Which layer is there? Epimysium. Then can you, people, see over here? Is it visible? Yes. Please reply. See. In simple term, muscle fiber means a muscle cell. Muscle fiber is a muscle cell. Agreed? Muscle fiber is a muscle cell. Nothing else. Now you see. What should be the outermost boundary of a cell? What should be the outermost boundary of a cell? Should it be the plasma membrane? Yes, sir. See. Can you see deep blue structure that is there over here and outside that grey one is there? Yes, sir. What is that deep blue structure known as? Deep blue structure is the sarcolemma. Outside sarcolemma, what is there? Endomysium. Which layer? Endomysium is there. Just outside the sarcolemma. Agreed, dear? Agreed? Tell me. Yes, sir. This. Come outside the outer abit. This light blue. This is known as perimysium. What? Perimysium. Agreed? This is going to form a muscle bundle. This is going to form a muscle bundle. Agreed? Perimysium. It is going to form a muscle bundle. Now you see. What is there between the muscle bundles? What is there between the muscle bundle? What is this? What is there between the muscle bundle? It is fascia. What is fascia? It is a connective tissue seed that connects muscle bundle. Yes or no? It is a connective tissue seed that connects muscle bundle. Agreed, dear? Everyone? Let's see. Sarcolemma is there. Then endomysium is there. Then perimysium is there. Then fascia is there. And the outermost layer is what? Epimysium. So can you arrange the layer inside to outside and outside to inside? Can you do that? Yes, sir. Then you people can draw the diagram. Then everyone? Yes, sir. Let's see. Similar structure is there for nerve also. Nerve. This is the exolema. Outside it. It is endonurium. For that, neurium word is used. Endomysium. Here endonurium. Then perineurium and outermost is epineurium. Yes or no? Similar thing is used for nerve also. Agreed, dear? Now? Yes. Please draw. Let's see. Let's see over here. This is muscle fiber. Outside muscle fiber. Sarcolemma is there. Agreed? And inside sarcolemma sarcoplasm is there. Agreed? Inside sarcoplasm, you people can observe many parallely arranged myofibrils. Done? Many parallely arranged myofibrils. Many parallely arranged myofibrils are there. No issues? Agreed? Do you people agree with this line? Please tell me. In sarcoplasm, there are many parallely arranged myofibrils are there. Agreed? Yes, sir. Yes. Now what? Myofibrils are made up of myofilaments. And NCRT has told myofilament and myofibrils are same. As per NCRT, but actually they are having difference in diameter. See fibers having more diameter. Fibrils having lesser and filament having even lesser diameter. Yes or no? It is because of that only definition is there. Let's see. Myofilament is of two types. One is actin myofilament. Another is myocin myofilament. Agreed, dear? Everyone? Agreed, dear? Actin myofilament and myocin myofilament. Do you people have any doubt in this? Tell me. Say yes or no? No, sir. Yes. Let's see over here. Actin is made up of filamentous actin, troponin and tropomyosin. And myosin is made up of, it is a polymer of meromyosin. Agreed? Here, actin and myosin are contractile protein and troponin, tropomyosin are regulatory protein. Agreed, dear? Are regulatory proteins. Agreed? Agreed? Yes, sir. Myosin, myofilament is made up of actin myofilament and myosin myofilament. Actin myofilament having filamentous actin, troponin and tropomyosin. And myosin myofilament having meromyosin as the constraint. Yes or no? Filamentous actin and myosin are there. They are contractile protein. Entroponin and tropomyosin are the regulatory protein. Agreed? No issues? Let's see. Actin filament is there. Here, can you see circles or many circles are there? What are they? They are globular actin. What? They are globular actin. Agreed, dear? Yes, sir. Globular actin. And when they will combine, they will form filamentous actin. What? Filamentous actin. Agreed, dear? So, can I say filamentous actin is a polymer of globular actin? Can I say that? Yes, sir. Agreed? And now, this blue one. This blue one is tropomyosin. What? That tropomyosin. Agreed? Yes. And on that, you can see there are three circles over here, gray color circle that is representing troponin. Actually, troponin is going to have three components. One is troponin I. One is troponin C. And one is troponin T. You see, actin filament is there, no? What is this? What is this? Myosin binding site. Myosin binding site is there, no? Okay. What do you think? What troponin I is doing? Is it masking the myosin binding site? Compare this situation and this situation. Please compare. Yes, it is masking the binding site. Agreed, dear? Everyone? Yes, sir. Yes. So, and what is the likely function of troponin C? Is it attaching itself to this calcium ion? Tell me, dear? Yes. What is the likely function of troponin C? Is it attaching to the calcium ion? And what is the likely function of troponin T? Is it attaching it to the tropomyosin? You see, when calcium arrives, it pulls it by combining with troponin C, leads to unmasking of myosin binding site present on actin filament. Yes or no? Tell me, release of calcium leads to binding of calcium to the troponin C, thus unmasking the myosin binding site present on the actin filament. Agreed? Yes, sir. Agreed? So, this is troponin. Done, everyone? Can you people understand troponin, tropomyosin and filamentous actin nicely and complete a structure of actin filament? You can draw this. Are we done? System in itself. Done, sir. Done? Yes. Next is myosin filament. It is a polymer of meromyosin. You can see the structure of meromyosin. You will get to know. See, there are two protein polypeptide with black. Okay? This is long polypeptide. And there are two. This blue is one in the head. This is short polypeptide. Agreed? Long polypeptide and short polypeptide. Agreed? So, can you see over here how many long polypeptide is there? Sir, two. And how many total short polypeptides are there? Four. So, total number of polypeptide in meromyosin is six. Six. It is an examer. This part is going to form the tail. This part is going to form the head. Head having long as well as short polypeptide, tail having only long polypeptide. Agreed? Done? So, you people need to see these things. Okay? Rest we will discuss in the next class because this will take time. Okay? And one thing, nodes of X-80 system I have already sent. It is there. It is in continuation with that node only. Everything is there in that node. Yes or no? You got that node? Yes. Yes. I am going to send this node now. Okay dear. Bye.