00:00 (upbeat music)

00:02 - Good day, everyone.

00:15 My name is Ms. Sakundi, I'm your biology teacher.

00:19 And today we are going to talk about the topic

00:22 regulation of internal environment, whom you stress is.

00:26 At the end of this lesson,

00:30 the student should be able to,

00:32 one, define the term whom you stress is,

00:36 two, they should be able to list the various organs

00:41 in our body that is involved in whom you stress is.

00:45 Three, they should also be able to list the function

00:50 of the kidney in whom you stress is.

00:55 And also describe the structure of the kidney

00:59 and the position of the kidney in the body.

01:04 The first thing we look at is the definition

01:07 of the term whom you stress is.

01:10 Homie stress is the maintenance of a steady state,

01:15 that is a state of consistency

01:17 in the internal environment of organisms.

01:21 The reason for regulating this internal environment

01:28 is because organisms have to perform optimally.

01:33 If every organ in the body is performing optimally.

01:38 And if the internal environment is nowhere regulated,

01:42 most of the organs will malfunction.

01:44 And once they do that, the body, the entire body

01:47 will malfunction.

01:48 And that is why body fluid, temperature,

01:52 ions in the body, like potassium, chloride,

01:56 another dissolved substances needs to be regulated.

02:01 And this regulation, the process of regulating

02:05 the entire system of the body is what we refer to

02:09 as homeostasis.

02:11 Now, what are the various organs that are involved

02:16 in the regulation of the body, of the internal structure?

02:23 We have about three main organs, one, the kidney.

02:28 The kidney function in regulating the internal environment.

02:33 We also have the liver, which is carrying out

02:37 a lot of processes to make sure that the internal environment

02:40 is at the optimal state.

02:43 Then we also have our skin.

02:44 And for these three organs to walk perfectly

02:49 and ensure that the internal environment

02:53 is regulated, they walk along with the nervous system

02:58 and the human now system.

03:01 Now, let's look at these organs one after the other

03:05 to see their function in homeostasis.

03:09 The first organ we are going to look at is the kidney.

03:13 Having done excretion, you know that the kidney

03:18 have several functions.

03:20 And one of the functions of the kidney is excretion,

03:24 which we have looked at before, under the topic excretion.

03:27 But what does this kidney look like?

03:31 If you look at the kidney, it's being shaped,

03:33 red in color.

03:34 And if you caught it open, you see that there are various

03:39 structures inside the kidney that helps the kidney

03:43 to carry out its function.

03:46 What are some of these structures?

03:48 If you look at the kidney, we have a picture of a kidney here.

03:51 And if you look at it, you see the rena colon,

03:56 the rena pyramid, the kapsu, the papili,

04:00 the minor calyx, the medulla, the major calyx,

04:03 the cortes, the rena pelvis, the otero pelvic

04:08 junction, and the ureta.

04:10 Then we also have the blood vessel, the rena artery,

04:13 and the rena vein, rena artery takes blood

04:16 into the kidney, where rena vein takes blood,

04:19 deoxygenated blood out of the kidney.

04:22 At the same time, it's also taking blood out

04:24 that is now having less concentration of urea.

04:29 That is, when the blood is going at, urea

04:33 would have been extracted from it.

04:35 And so the blood coming out is having less concentration

04:39 of urea.

04:40 And that is the function of the kidney in excretion.

04:44 But apart from this, the excretion

04:49 and others, a function of the kidney,

04:52 like osmo regulation and acid based balance,

04:54 they all work together to ensure that the internal environment

04:59 is at optimal level.

05:02 Now, looking at the structure of the kidney,

05:06 you see that every mama have two kidneys that are attached

05:12 to the dose wall of the abdominal cavity.

05:17 The rena artery and the rena vein, they join the ureta

05:23 as it enters the kidney.

05:26 At the top of each kidney, that is, you have the bean shape.

05:30 Then at the top of each of the kidney,

05:32 you have the rena gland.

05:35 Then also, the left kidney is slightly higher

05:40 in position.

05:41 That is the attached one is attached slightly higher

05:44 than the other one.

05:46 So the left kidney is slightly higher

05:49 than the right kidney in the attachment.

05:54 Each kidney lies on either side of the vertebral column.

06:00 So I believe now you can picture where your kidneys are

06:04 and how they are positioned.

06:07 Like I said before, each kidney is bean shaped and red in color.

06:15 Each is surrounded by a fibrous capsule

06:19 and also covered with some fat to protect it

06:24 and insulate it and also keep it in position.

06:30 We said the rena artery carries oxygenated blood

06:34 which urea and anything that is to be removed from the body

06:39 into the kidney.

06:41 And after our trophatration, if there is need

06:45 for selective reabsorption, take place,

06:47 the rena vein carries out the deoxygenated blood

06:51 that I have said before have less concentration of urea.

06:58 And any other toxic substance that needs to be removed by the kidney

07:02 would have been removed at this time.

07:04 But the ureta is the one that brings out the urine

07:10 from the kidney and passes it to the bladder.

07:14 So that tube that connects the kidney to the bladder

07:19 is what we refer to as the ureta.

07:23 Here we have the longitudinal section of the kidney

07:26 and we can see the major division.

07:30 The outer division of the kidney is called the cortex.

07:34 The inner side of the kidney is called the medulla.

07:39 Then the junction at which all this tube, the ureta,

07:44 the rena artery, the rena vein enters

07:47 and leave the kidney is called the pelvis.

07:50 The cortex is the outer layer.

07:56 And we have the malpigian tubers having their capsule,

08:05 the bone and capsule, the proximal covaluted tubo,

08:08 and also the collecting dots and the distal covaluted tubo

08:13 inside the cortex.

08:14 Why the loop of Henley, which we have looked at before in excretion,

08:20 is found in the medulla?

08:26 The medulla is the inner layer, like I said before.

08:30 And the part of the nephron, which we call the loop of Henley,

08:35 is found in the medulla.

08:38 And when it comes out, it goes directly to the pyramid.

08:43 Now, we come to the function of the kidney.

08:46 I have mentioned before that the kidney

08:48 have three main functions in homeostasis.

08:54 And what are these functions?

08:57 One, we have the first one, which is excretion.

09:10 Excretion is the main function of the kidney

09:19 that we are all very familiar with.

09:21 We know that your information takes place in the kidney.

09:24 So we are more familiar with excretion.

09:27 Apart from removing urea from our body,

09:30 excretion also helps in regulating the internal environment.

09:35 Remember, urea is a toxic substance.

09:38 And the reason the kidney is removing it

09:40 is for the body not to be poisoned by it,

09:44 keeping it in the optimal level.

09:47 The second one is osmo-regulation.

09:51 This is the control of the amount of water in the body.

10:01 So the kidney is for me, urea is also helping

10:05 to control the level of water in the body

10:08 so that the body will function optimally.

10:11 And the third one is acid-based balance.

10:20 Now, what we talk about acid-based balance?

10:25 We are talking about the amount of ions in the body,

10:30 the acidity of body fluid, blood and the other body fluid,

10:35 and the amount of salts.

10:39 Water balance with dissolved substances.

10:42 That is what we refer to as acid-based balance.

10:46 The kidney also helps in regulating the blood pH.

10:50 Making sure that it's neither too acidic nor too basic.

10:55 Just right at around 7.2, which the body needs

10:59 to perform optimally.

11:01 Now, let's look at this function one after the other.

11:04 Let's take the first one excretion.

11:07 Excretion we have talked about before,

11:09 when we dealt with excretion during formation as a topic.

11:13 So we may not go in depth in that,

11:14 but you know that during excretion,

11:16 the body removes toxic material.

11:18 The kidney helps to remove urea, drugs, anything

11:22 that may be harmful to the body is extracted from blood

11:27 and excreted out with urine.

11:29 So the one we focus here today is number two and number three.

11:34 So now, let's look at number two.

11:36 Osmo regulation.

11:39 Osmo regulation is the balance of water,

11:44 the level of water in blood and in body fluid.

11:47 This must be controlled.

11:50 If it is too much, it will be harmful.

11:52 And if it is too little, it will also be harmful.

11:55 So a certain level has to be maintained.

11:58 And the maintainers of this level of water

12:01 is what we refer to as Osmo regulation.

12:05 How does the kidney carry out Osmo regulation?

12:08 How does it regulate the amount of water in our body?

12:12 Remember, when we talked about the organs

12:16 that are involved in Osmo regulation,

12:20 I did mention that for these three organs to work perfectly,

12:25 that there is need for them to work hand in hand

12:27 with the nervous system and the hormonal system.

12:31 So let's have that at the back of our mind,

12:33 as we look at a kidney control of our water balance,

12:37 which is Osmo regulation.

12:40 Now, for the kidney to carry out Osmo regulation,

12:45 it needs to work with a hormone called ADH, anti-duretic hormone.

12:53 This hormone is secreted from the pituitary gland,

12:56 which is at the base of our brain.

12:59 But before ADH can be secreted,

13:04 the hypothalamus of the brain, most best of all,

13:08 detects that either the aspotic pressure is high

13:12 or is low for ADH to be secreted.

13:16 So the nervous system has to be involved

13:18 and also the hormonal system.

13:21 So how does it work?

13:24 We have to look at it when the blood level of water

13:28 is too low and when it is high.

13:32 Now, let's take on a hot day.

13:36 You are sweating.

13:38 You are not taking enough water.

13:40 You are just taking water normally,

13:42 while you are sweating, you're related.

13:45 And the amount of water in your body has gone down.

13:49 What happens?

13:51 How does the kidney make sure that you don't get to the point

13:56 where the level of water is harmful to the body?

14:00 What we happen is that as blood is flowing in your body,

14:05 it gets to the brain.

14:06 And then it flows through the hypothalamus.

14:10 And as it flows through the hypothalamus,

14:12 inside the hypothalamus, there are osmo detectors.

14:18 That will detect that the amount of water in the body is low

14:22 because the osmotic pressure will be high.

14:27 So once your osmotic pressure is high,

14:29 it shows that the amount of water in the body is low.

14:32 It will send a message to the pituitary gland

14:35 to secrete adhesh into the blood.

14:37 Now, this adhesh is now carried by the blood to the kidney.

14:42 What does it do in the kidney?

14:44 Once it gets to the kidney,

14:46 it makes every part of the kidney

14:49 to be permeable to water.

14:51 So when autofiltration takes place, water filters out

14:55 instead of just excreting the water out as urine.

14:59 Major part of that water is reabsorbed into the blood,

15:04 back into the blood.

15:06 And once this is done, it will continue doing it,

15:09 making sure that the water is not being sent out

15:13 but taking back into the blood.

15:15 And as it continues doing that,

15:17 a time when the level of water will come back to normal.

15:22 And once the level of water comes back to normal,

15:25 the blood, remember, is still flowing through the pituitary gland.

15:29 The hypothalamus sensitive that it is now normal.

15:33 So it stops sending the message to the pituitary gland

15:37 to secrete adhesh.

15:39 And the secretion of adhesh is stopped.

15:41 And once that is stopped, the kidney tubers are normal.

15:45 The every part of it will no more be permeable to water.

15:48 So now the urine can be excreted.

15:51 So with that, on a hot day, our water balance is kept

15:55 at the normal level because the kidney now holds back

15:59 the removal of water from our body.

16:03 But if the water is cold and I drown so much water,

16:06 what happens?

16:07 The thing is that nothing will happen.

16:12 Why did I say nothing will happen?

16:14 The reason is this.

16:15 The pituitary gland will not recognize

16:18 high osmotic pressure from the blood.

16:20 And so every water that feed us is just passed out

16:25 with urine.

16:26 And because of the water being passed out,

16:29 if it is too high for the body,

16:31 the passing out of the water will reduce it back to normal.

16:35 So with that, the level of water in our body

16:39 is controlled at the optimal stage.

16:43 But there is a situation in which the secretion of ADH

16:49 is hindered by some other things.

16:52 And if we have a condition where the pituitary gland cannot

16:55 secret ADH, we now have a condition

16:59 called diabetes in Cepidos.

17:02 In which no matter how dehydrated the person is,

17:06 it's passed out urine normally and frequently,

17:10 making that individual to be dehydrated.

17:14 And at that time, there would be need for treatment

17:18 for this condition to be taken care of.

17:21 Or else, the person may end up dying

17:24 because of the level of water in the body.

17:31 Now, the pH of body fluid, blood,

17:35 should be kept at 7.3 to 7.5.

17:39 Below this range is dangerous.

17:41 And higher than it, we also affect the body.

17:46 So, the body needs to be kept at this level

17:50 for it to function optimally.

17:53 The maintenance of osmotic pressure,

17:59 if the pressure of the body begins to fall.

18:02 Like I said before, the hypothalamus

18:04 can only read the osmotic pressure of blood.

18:08 If it drops below a certain point,

18:12 then the entire system will pack up.

18:15 And this is the reason why homostasis

18:18 is a very, very important aspect of the human body

18:23 or body of a mama's in particular.

18:26 Because of the father's, we are won't blooded.

18:30 And so many things can be affected

18:33 if the water level is not maintained.

18:38 Severatins can affect our removal or control

18:43 of our water level.

18:44 Drugs, alcohol, toxins, things like that.

18:48 When they enter the body, interface with the normal process

18:52 of osmo regulation.

18:54 And that can lead to a lot of problems.

18:58 So, we also want to talk about acid-based balance.

19:05 How does the kidney control the acidity

19:11 or the bezicity of blood?

19:14 We have said it controls osmo regulation,

19:18 the level of water.

19:19 How does it control acidity and bezicity of blood?

19:24 And sometimes we want that blood really be acidic or basic.

19:27 Yes, because like I said before,

19:30 the level to be maintained is 7.3 to 7.4.

19:34 If you eat a lot of acidic food,

19:37 the tendency of having a lot of hydrogen ion

19:40 circulating in your system is there.

19:43 And so, the blood becomes acidic.

19:47 When that happens, the kidney tries to bring it back

19:50 to the normal 7.3 to 7.4.

19:55 How is that done?

19:56 Very simple.

19:58 Remember the kidney tube that is involved in excretion.

20:03 When ultra-fetration takes place,

20:06 this tiny ions may still remain in the blood.

20:09 They may not come out.

20:11 But if the blood is acidic,

20:14 what the kidney does is, as the urine is flowing

20:19 from the proximal convoluted tube

20:22 through the loop of Henley, which I've said is found

20:25 in the medulla, going up to the distal convoluted tube

20:30 to get to the collecting dirt.

20:31 When it gets to the distal convoluted tube,

20:35 what we happen is the body having realized that the blood

20:40 is acidic.

20:41 That means the pH is lower than normal.

20:44 We secrete hydrogen ion into the urine.

20:49 That by increasing the pH back to 7.3.

20:57 But if we are eating a lot of basically like some of us

20:59 like food like they have cowl salts and things like that,

21:04 the blood pH will be higher.

21:07 That is, it's basic now.

21:08 Both 7, it is basic.

21:10 So what we the kidney do?

21:12 When the blood is flowing, as he also

21:13 gets to the distal convoluted tube,

21:16 salt will be secreted into the urine from the blood.

21:23 And as this salt is secreted, it drops the pH back to between 7.3

21:29 to 7.4.

21:31 That by keeping the pH of body fluid

21:36 and blood at a normal optimum level.

21:40 So with this, the kidney is able to help us to maintain

21:47 a steady stable internal environment.

21:52 By controlling the level of water, by removing

21:55 waste products and toxic products, and also by controlling

22:01 our acid base.

22:03 And making sure that the balance is always there.

22:06 And body fluid and blood is always

22:09 maintain a long and neutral range of 7.3 to 7.4.

22:17 With this, so with this, we end

22:25 the lesson for today.

22:27 Till next time, I remain Mrs. Sarkandhi.

22:30 Thank you.