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1
Rinea Kitsch
11/22/2025
Science
SCIENCE L1: RESPIRATORY SYSTEM
1,031
•
Nov 22, 2025
•
Understanding the Respiratory System: Science Notes L1
Rinea Kitsch
@rineakitsch
1 / 10
The Human Respiratory System
Your respiratory system is basically your body's air delivery service! It's made up of organs and tissues that work together to grab oxygen from the air you breathe and get rid of carbon dioxide your cells don't need.
Think of it like a two-way highway - oxygen comes in, carbon dioxide goes out. This process is called breathing or external respiration, and it's happening right now as you read this.
Quick Fact: You breathe about 20,000 times a day without even thinking about it!
The Oxygen Journey
Picture yourself as a tiny oxygen molecule going on an epic adventure through your body! You'd start by entering through the nose or mouth, then travel through several stops before reaching your final destination.
Your journey would take you through the pharynx (throat), down the larynx (voice box), and into the trachea (windpipe). From there, you'd split paths into the bronchi, which branch into smaller bronchioles like tree branches.
Finally, you'd arrive at tiny air sacs called alveoli where the real magic happens - gas exchange! Here, oxygen jumps into the bloodstream while carbon dioxide jumps out to be exhaled.
Remember This: The path is like a upside-down tree - starting with one trunk (trachea) that branches out into millions of tiny leaves (alveoli).
Your Nose: The Body's Air Filter
Your nose isn't just for smelling - it's actually a super sophisticated air treatment center! The nasal cavity inside your nose does three important jobs before air reaches your lungs.
First, it acts like a filter, catching dust and particles so they don't make it to your lungs. Second, it warms up cold air and adds moisture so your lungs get air that's just the right temperature and humidity.
As a bonus, your nose also contains olfactory receptors that give you your sense of smell. That's why food doesn't taste as good when you have a stuffy nose!
Pro Tip: Breathing through your nose is better than mouth breathing because it filters and prepares the air better.
Mouth and Throat: Backup Systems
Your mouth and oral cavity serve as Plan B when your nose is blocked. While not as efficient as nose breathing, mouth breathing keeps you alive when you have a cold or allergies.
The pharynx (throat) is like a busy intersection where air and food pathways cross. It connects your nasal cavity and mouth to the trachea, but it has to handle both breathing and swallowing.
The epiglottis is your body's smart traffic controller - it's a flap that covers your windpipe when you swallow, making sure food goes to your stomach and not your lungs.
Safety Feature: That choking feeling when something "goes down the wrong pipe" is your epiglottis working to protect your airways!
Voice Box and Windpipe: The Highway System
Your larynx (voice box) is more than just what makes your voice - it's a flexible, tough tube that connects your throat to your windpipe. It keeps your airway open while making sure food and drinks can't block your breathing.
The trachea (windpipe) is like a major highway for air - it's a wide, hollow tube that carries air between your voice box and your lungs. It prepares the air by getting it to the perfect temperature and humidity.
Think of the trachea as the main trunk of your respiratory tree, getting ready to branch out into your lungs where all the important gas exchange happens.
Cool Connection: Your voice works because air from your lungs vibrates your vocal cords in the larynx - no air flow, no voice!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
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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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Understanding the Respiratory System: Science Notes L1
Rinea Kitsch
@rineakitsch
Ever wonder how you breathe without even thinking about it? Your respiratory system is an amazing network that works 24/7 to keep you alive by bringing oxygen into your body and removing carbon dioxide waste.
The Human Respiratory System
Your respiratory system is basically your body's air delivery service! It's made up of organs and tissues that work together to grab oxygen from the air you breathe and get rid of carbon dioxide your cells don't need.
Think of it like a two-way highway - oxygen comes in, carbon dioxide goes out. This process is called breathing or external respiration, and it's happening right now as you read this.
Quick Fact: You breathe about 20,000 times a day without even thinking about it!
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The Oxygen Journey
Picture yourself as a tiny oxygen molecule going on an epic adventure through your body! You'd start by entering through the nose or mouth, then travel through several stops before reaching your final destination.
Your journey would take you through the pharynx (throat), down the larynx (voice box), and into the trachea (windpipe). From there, you'd split paths into the bronchi, which branch into smaller bronchioles like tree branches.
Finally, you'd arrive at tiny air sacs called alveoli where the real magic happens - gas exchange! Here, oxygen jumps into the bloodstream while carbon dioxide jumps out to be exhaled.
Remember This: The path is like a upside-down tree - starting with one trunk (trachea) that branches out into millions of tiny leaves (alveoli).
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Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your Nose: The Body's Air Filter
Your nose isn't just for smelling - it's actually a super sophisticated air treatment center! The nasal cavity inside your nose does three important jobs before air reaches your lungs.
First, it acts like a filter, catching dust and particles so they don't make it to your lungs. Second, it warms up cold air and adds moisture so your lungs get air that's just the right temperature and humidity.
As a bonus, your nose also contains olfactory receptors that give you your sense of smell. That's why food doesn't taste as good when you have a stuffy nose!
Pro Tip: Breathing through your nose is better than mouth breathing because it filters and prepares the air better.
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
Mouth and Throat: Backup Systems
Your mouth and oral cavity serve as Plan B when your nose is blocked. While not as efficient as nose breathing, mouth breathing keeps you alive when you have a cold or allergies.
The pharynx (throat) is like a busy intersection where air and food pathways cross. It connects your nasal cavity and mouth to the trachea, but it has to handle both breathing and swallowing.
The epiglottis is your body's smart traffic controller - it's a flap that covers your windpipe when you swallow, making sure food goes to your stomach and not your lungs.
Safety Feature: That choking feeling when something "goes down the wrong pipe" is your epiglottis working to protect your airways!
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
Voice Box and Windpipe: The Highway System
Your larynx (voice box) is more than just what makes your voice - it's a flexible, tough tube that connects your throat to your windpipe. It keeps your airway open while making sure food and drinks can't block your breathing.
The trachea (windpipe) is like a major highway for air - it's a wide, hollow tube that carries air between your voice box and your lungs. It prepares the air by getting it to the perfect temperature and humidity.
Think of the trachea as the main trunk of your respiratory tree, getting ready to branch out into your lungs where all the important gas exchange happens.
Cool Connection: Your voice works because air from your lungs vibrates your vocal cords in the larynx - no air flow, no voice!
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
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
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
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
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
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user