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Ummi
12/12/2025
Biology
The Kidney
64
•
12 Dec 2025
•
Understanding the Kidney: Structure, Functions, and Common Diseases
Ummi
@ummi_.com
1 / 4
Kidney Structure and the Amazing Nephron
Think of your kidneys as sophisticated filtration systems sitting just behind your abdominal cavity, one on each side of your spine. Each kidney contains about a million nephrons - tiny filtering units that do the real work of cleaning your blood.
The nephron is where all the magic happens. It starts with the glomerulus, a cluster of tiny blood vessels that act like a super-fine sieve. This is wrapped by Bowman's capsule, which catches all the filtered liquid - imagine it like a baseball glove catching what falls through the sieve.
Quick Fact: Each of your kidneys processes about 120-150 litres of blood every single day - that's like filtering a bathtub full of blood!
Understanding these basic structures sets you up perfectly for grasping how your kidneys actually clean your blood and make urine.
The Nephron's Journey: From Filter to Urine
After the initial filtering, the liquid travels through several important stops in the nephron. The proximal convoluted tubule (PCT) is like a recycling centre - it grabs back most of the water, glucose, and useful nutrients that your body wants to keep.
Next comes the loop of Henle, a hairpin-shaped tube that dips down into the kidney's inner layer. This clever structure creates a concentration gradient that helps your body reabsorb water when you need it most.
The distal convoluted tubule (DCT) provides the final touch-ups, adjusting what gets reabsorbed or secreted. Finally, the collecting duct gathers urine from multiple nephrons and sends it towards your bladder.
Remember: The nephron is basically a sophisticated recycling and waste disposal system all rolled into one!
How Your Kidneys Keep You Healthy
Your kidneys perform three main jobs that keep your body running smoothly. Filtration happens first - your glomerulus acts like a bouncer, letting waste and excess water through whilst keeping essential proteins and blood cells in your bloodstream.
Reabsorption is the recycling process where your PCT, loop of Henle, and DCT grab back valuable substances like water, glucose, and amino acids. Meanwhile, secretion allows your DCT to actively dump additional waste products into the urine.
Beyond making urine, your kidneys are hormone factories. They produce erythropoietin (which tells your bone marrow to make more red blood cells), renin (which helps control blood pressure), and calcitriol (the active form of vitamin D).
Key Point: Your kidneys don't just filter waste - they're master regulators of blood pressure, electrolyte balance, and even red blood cell production!
When Kidneys Go Wrong: Common Diseases
Kidney failure is the most serious condition, where your kidneys lose their ability to filter waste effectively. This can happen gradually (chronic) or suddenly (acute), and may require dialysis or transplantation.
Kidney stones form when minerals crystallise in your kidneys, creating painful deposits that can block urine flow. Glomerulonephritis involves inflammation of the glomeruli, often triggered by infections or autoimmune diseases attacking your own kidney tissue.
Polycystic kidney disease is a genetic condition where fluid-filled cysts grow throughout the kidneys, gradually reducing their function. This shows why understanding kidney structure is so important - when these parts don't work properly, serious health problems follow.
Health Tip: Drinking plenty of water, eating a balanced diet, and avoiding excessive salt can help keep your kidneys healthy throughout your life!
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Basil
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This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
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In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
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I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Understanding the Kidney: Structure, Functions, and Common Diseases
Ummi
@ummi_.com
Your kidneys are bean-shaped powerhouses working 24/7 to keep you alive and healthy. These incredible organs filter your blood, remove waste, and maintain the perfect balance of water and chemicals in your body.
Kidney Structure and the Amazing Nephron
Think of your kidneys as sophisticated filtration systems sitting just behind your abdominal cavity, one on each side of your spine. Each kidney contains about a million nephrons - tiny filtering units that do the real work of cleaning your blood.
The nephron is where all the magic happens. It starts with the glomerulus, a cluster of tiny blood vessels that act like a super-fine sieve. This is wrapped by Bowman's capsule, which catches all the filtered liquid - imagine it like a baseball glove catching what falls through the sieve.
Quick Fact: Each of your kidneys processes about 120-150 litres of blood every single day - that's like filtering a bathtub full of blood!
Understanding these basic structures sets you up perfectly for grasping how your kidneys actually clean your blood and make urine.
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The Nephron's Journey: From Filter to Urine
After the initial filtering, the liquid travels through several important stops in the nephron. The proximal convoluted tubule (PCT) is like a recycling centre - it grabs back most of the water, glucose, and useful nutrients that your body wants to keep.
Next comes the loop of Henle, a hairpin-shaped tube that dips down into the kidney's inner layer. This clever structure creates a concentration gradient that helps your body reabsorb water when you need it most.
The distal convoluted tubule (DCT) provides the final touch-ups, adjusting what gets reabsorbed or secreted. Finally, the collecting duct gathers urine from multiple nephrons and sends it towards your bladder.
Remember: The nephron is basically a sophisticated recycling and waste disposal system all rolled into one!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
How Your Kidneys Keep You Healthy
Your kidneys perform three main jobs that keep your body running smoothly. Filtration happens first - your glomerulus acts like a bouncer, letting waste and excess water through whilst keeping essential proteins and blood cells in your bloodstream.
Reabsorption is the recycling process where your PCT, loop of Henle, and DCT grab back valuable substances like water, glucose, and amino acids. Meanwhile, secretion allows your DCT to actively dump additional waste products into the urine.
Beyond making urine, your kidneys are hormone factories. They produce erythropoietin (which tells your bone marrow to make more red blood cells), renin (which helps control blood pressure), and calcitriol (the active form of vitamin D).
Key Point: Your kidneys don't just filter waste - they're master regulators of blood pressure, electrolyte balance, and even red blood cell production!
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
When Kidneys Go Wrong: Common Diseases
Kidney failure is the most serious condition, where your kidneys lose their ability to filter waste effectively. This can happen gradually (chronic) or suddenly (acute), and may require dialysis or transplantation.
Kidney stones form when minerals crystallise in your kidneys, creating painful deposits that can block urine flow. Glomerulonephritis involves inflammation of the glomeruli, often triggered by infections or autoimmune diseases attacking your own kidney tissue.
Polycystic kidney disease is a genetic condition where fluid-filled cysts grow throughout the kidneys, gradually reducing their function. This shows why understanding kidney structure is so important - when these parts don't work properly, serious health problems follow.
Health Tip: Drinking plenty of water, eating a balanced diet, and avoiding excessive salt can help keep your kidneys healthy throughout your life!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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Most popular content: Excretory System
Most popular content in Biology
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Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user