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Dec 15, 2025
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Understanding the Human Respiratory System
A
Angel
@angel_87ncr
1 / 5
The Respiratory System: How You Breathe
Did you know that every single breath you take involves four different processes? Biology teaches us that our bodies are amazing machines, and breathing is way more complex than just air going in and out!
Respiration is the overall process of getting oxygen and removing carbon dioxide from your body. Don't confuse this with just breathing - that's only one part! The four phases are: breathing (moving air in and out), external respiration (gas exchange in lungs), internal respiration (gas exchange with body cells), and cellular respiration (using oxygen to release energy from food).
Your respiratory system includes your nose, throat, windpipe, and lungs - all working together like a perfectly designed air conditioning system. The air you breathe needs to be filtered, warmed, and moistened before it reaches your delicate lung tissues. Your nose hairs and cilia act like tiny bouncers, trapping dust and germs that could harm your lungs.
Quick Tip: The tiny air sacs in your lungs called alveoli are where the real magic happens - oxygen enters your blood and carbon dioxide gets removed!
Your Breathing Highway: Upper and Lower Respiratory Tract
Think of your respiratory system as a highway system with specific stops along the way! The upper respiratory tract includes your nostrils, nasal cavities, pharynx (throat), and larynx (voice box). Fun fact: boys develop Adam's apples during puberty because their larynx grows bigger than girls' do!
The lower respiratory tract is where things get really interesting. Your trachea (windpipe) is supported by C-shaped cartilage rings - kind of like a vacuum cleaner hose that won't collapse. From there, air travels through the bronchi (two main tubes) and then into smaller bronchioles.
Your lungs are the star players here - spongy organs protected by your rib cage and surrounded by a thin membrane called the pleura. They're divided into sections called lobes, and they're where all the gas exchange happens. The diaphragm, a large dome-shaped muscle below your lungs, does the heavy lifting by contracting and relaxing to help you breathe.
Remember This: When you inhale, your ribs move out to expand chest space. When you exhale, they move in to decrease space - it's like your chest is a bellows!
Gas Exchange and Respiratory Diseases
Your body is constantly trading gases with the environment through gas exchange - oxygen in, carbon dioxide out! This happens in two ways: external respiration (between your lungs and the environment) and internal respiration (between your blood and body cells). Different animals have different systems - humans use lungs, fish use gills, and insects have tracheal systems.
Unfortunately, your respiratory system can face several health challenges. Common cold and influenza are viral infections you've probably experienced. More serious conditions include pneumonia (lung infection), tuberculosis (bacterial infection), and asthma (chronic condition that narrows airways).
COVID-19 taught us all about respiratory diseases caused by viruses that can seriously affect breathing. Other long-term problems include lung cancer (often from smoking) and emphysema (lung damage from irritants). Bronchitis involves inflammation of your bronchial tubes, making breathing difficult.
Health Tip: The best way to protect your respiratory system is to avoid smoking, stay active, wash your hands frequently, and get vaccinated when recommended!
Your Heart: The Ultimate Pump
Your cardiovascular system is like your body's delivery service, with your heart as the main distribution center! This system includes your heart, blood vessels, and blood - all working 24/7 to keep you alive.
Your heart is a muscular pump protected by tissue called the pericardium. It has four chambers: two atria (upper chambers that collect blood) and two ventricles (lower chambers that pump blood out). The right side handles oxygen-poor blood while the left side handles oxygen-rich blood. Four valves prevent blood from flowing backward - they make that "lub-dub" sound you hear!
Blood is often called the "river of life" because it transports everything your cells need. It has three main jobs: transport (carrying oxygen, nutrients, and hormones), protection (fighting infections), and temperature regulation (keeping your body at the right temperature).
Amazing Fact: Your heart beats about 100,000 times per day, pumping roughly 2,000 gallons of blood through your body!
Blood Components and Circulation
Your blood is basically a liquid highway carrying different types of "vehicles"! Plasma makes up most of your blood - it's a pale yellow liquid that's 92% water. The rest consists of different blood cells, each with special jobs.
Red blood cells (erythrocytes) are your oxygen delivery trucks. They're disk-shaped and packed with hemoglobin, the protein that makes blood red and carries oxygen. They live about 120 days. White blood cells (leukocytes) are your body's security force - they fight infections and increase in number when you're sick. Platelets (thrombocytes) are like tiny repair crews that help your blood clot when you get cut.
Your blood vessels form a closed circuit throughout your body. Arteries carry oxygen-rich blood away from your heart (think "A" for away). Veins bring oxygen-poor blood back to your heart. Capillaries are tiny vessels that connect arteries and veins - they're where nutrients and oxygen actually reach your cells.
Cool Connection: Your body has two major circulation routes - pulmonary circulation (heart to lungs and back) and systemic circulation (heart to body and back)!
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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 Human Respiratory System
A
Angel
@angel_87ncr
Biology is basically the science that studies all living things, including how our own bodies work! In this lesson, you'll discover how your respiratory system helps you breathe and how your cardiovascular system pumps blood throughout your body - two... Show more
The Respiratory System: How You Breathe
Did you know that every single breath you take involves four different processes? Biology teaches us that our bodies are amazing machines, and breathing is way more complex than just air going in and out!
Respiration is the overall process of getting oxygen and removing carbon dioxide from your body. Don't confuse this with just breathing - that's only one part! The four phases are: breathing (moving air in and out), external respiration (gas exchange in lungs), internal respiration (gas exchange with body cells), and cellular respiration (using oxygen to release energy from food).
Your respiratory system includes your nose, throat, windpipe, and lungs - all working together like a perfectly designed air conditioning system. The air you breathe needs to be filtered, warmed, and moistened before it reaches your delicate lung tissues. Your nose hairs and cilia act like tiny bouncers, trapping dust and germs that could harm your lungs.
Quick Tip: The tiny air sacs in your lungs called alveoli are where the real magic happens - oxygen enters your blood and carbon dioxide gets removed!
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Your Breathing Highway: Upper and Lower Respiratory Tract
Think of your respiratory system as a highway system with specific stops along the way! The upper respiratory tract includes your nostrils, nasal cavities, pharynx (throat), and larynx (voice box). Fun fact: boys develop Adam's apples during puberty because their larynx grows bigger than girls' do!
The lower respiratory tract is where things get really interesting. Your trachea (windpipe) is supported by C-shaped cartilage rings - kind of like a vacuum cleaner hose that won't collapse. From there, air travels through the bronchi (two main tubes) and then into smaller bronchioles.
Your lungs are the star players here - spongy organs protected by your rib cage and surrounded by a thin membrane called the pleura. They're divided into sections called lobes, and they're where all the gas exchange happens. The diaphragm, a large dome-shaped muscle below your lungs, does the heavy lifting by contracting and relaxing to help you breathe.
Remember This: When you inhale, your ribs move out to expand chest space. When you exhale, they move in to decrease space - it's like your chest is a bellows!
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Gas Exchange and Respiratory Diseases
Your body is constantly trading gases with the environment through gas exchange - oxygen in, carbon dioxide out! This happens in two ways: external respiration (between your lungs and the environment) and internal respiration (between your blood and body cells). Different animals have different systems - humans use lungs, fish use gills, and insects have tracheal systems.
Unfortunately, your respiratory system can face several health challenges. Common cold and influenza are viral infections you've probably experienced. More serious conditions include pneumonia (lung infection), tuberculosis (bacterial infection), and asthma (chronic condition that narrows airways).
COVID-19 taught us all about respiratory diseases caused by viruses that can seriously affect breathing. Other long-term problems include lung cancer (often from smoking) and emphysema (lung damage from irritants). Bronchitis involves inflammation of your bronchial tubes, making breathing difficult.
Health Tip: The best way to protect your respiratory system is to avoid smoking, stay active, wash your hands frequently, and get vaccinated when recommended!
Sign up to see the contentIt's free!
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Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Your Heart: The Ultimate Pump
Your cardiovascular system is like your body's delivery service, with your heart as the main distribution center! This system includes your heart, blood vessels, and blood - all working 24/7 to keep you alive.
Your heart is a muscular pump protected by tissue called the pericardium. It has four chambers: two atria (upper chambers that collect blood) and two ventricles (lower chambers that pump blood out). The right side handles oxygen-poor blood while the left side handles oxygen-rich blood. Four valves prevent blood from flowing backward - they make that "lub-dub" sound you hear!
Blood is often called the "river of life" because it transports everything your cells need. It has three main jobs: transport (carrying oxygen, nutrients, and hormones), protection (fighting infections), and temperature regulation (keeping your body at the right temperature).
Amazing Fact: Your heart beats about 100,000 times per day, pumping roughly 2,000 gallons of blood through your body!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Blood Components and Circulation
Your blood is basically a liquid highway carrying different types of "vehicles"! Plasma makes up most of your blood - it's a pale yellow liquid that's 92% water. The rest consists of different blood cells, each with special jobs.
Red blood cells (erythrocytes) are your oxygen delivery trucks. They're disk-shaped and packed with hemoglobin, the protein that makes blood red and carries oxygen. They live about 120 days. White blood cells (leukocytes) are your body's security force - they fight infections and increase in number when you're sick. Platelets (thrombocytes) are like tiny repair crews that help your blood clot when you get cut.
Your blood vessels form a closed circuit throughout your body. Arteries carry oxygen-rich blood away from your heart (think "A" for away). Veins bring oxygen-poor blood back to your heart. Capillaries are tiny vessels that connect arteries and veins - they're where nutrients and oxygen actually reach your cells.
Cool Connection: Your body has two major circulation routes - pulmonary circulation (heart to lungs and back) and systemic circulation (heart to body and back)!
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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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