Biology
Chemistry
AP Chemistry
English
AP English Literature
653
•
Nov 24, 2025
•
izzy
@izzy_mac
Your cardiovascular system is basically your body's delivery service, constantly... Show more
Ever wondered why your heart pounds during a sprint? Your cardiovascular system has three main parts - the heart, blood, and blood vessels - all working together to keep your muscles supplied with what they need during physical activity.
Your heart works like a double pump with two separate circuits. The pulmonary circuit handles the "dirty" blood - deoxygenated blood flows from your right ventricle through the pulmonary artery to your lungs, gets cleaned up with fresh oxygen, then returns to your left atrium via pulmonary veins.
The systemic circuit delivers the goods to your body. Oxygenated blood shoots out from your left ventricle through the massive aorta, travels to all your muscles and organs, then returns as deoxygenated blood through the vena cava to your right atrium. It's like a perfectly timed relay race that never stops!
Quick Tip: Remember the circuits by thinking "Right = Respiratory" (pulmonary circuit starts from right side) and "Left = Life" (systemic circuit starts from left side to supply your whole body).
Think of blood vessels as a three-tier transport system, each designed for different jobs. Arteries are like motorways - they've got thick, muscular walls and narrow lumens because they handle high-pressure blood rushing away from your heart. Most carry oxygenated blood, except for those sneaky pulmonary arteries heading to your lungs.
Veins are more like country roads - they have thinner walls, wider lumens, and special valves to prevent blood from flowing backwards as it travels back to your heart under much lower pressure. Capillaries are the tiny back streets where all the real action happens - their walls are just one cell thick, allowing oxygen and nutrients to slip through to your tissues.
Each type of vessel is perfectly designed for its job. The thick, elastic artery walls can stretch and bounce back with each heartbeat, whilst the wide vein lumens make it easier for blood to flow back to your heart against gravity.
Your blood is like a busy transport network with different workers doing specific jobs. Red blood cells are the oxygen delivery drivers - they pick up oxygen from your lungs and drop it off at your muscles, then collect carbon dioxide waste for the return journey.
White blood cells act as your personal security team, fighting off infections and diseases that try to invade your body. Platelets are like emergency repair workers - when you get a cut, they rush to the scene and help your blood clot to stop the bleeding.
All these cells float around in plasma, which is basically the liquid motorway that carries everything through your bloodstream. Plasma also transports nutrients, hormones, and waste products around your body, making it essential for keeping everything running smoothly.
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.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
App Store
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
izzy
@izzy_mac
Your cardiovascular system is basically your body's delivery service, constantly moving oxygen, nutrients, and waste products around through an amazing network of tubes and pumps. Understanding how your heart, blood vessels, and blood work together will help you grasp why... Show more
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Ever wondered why your heart pounds during a sprint? Your cardiovascular system has three main parts - the heart, blood, and blood vessels - all working together to keep your muscles supplied with what they need during physical activity.
Your heart works like a double pump with two separate circuits. The pulmonary circuit handles the "dirty" blood - deoxygenated blood flows from your right ventricle through the pulmonary artery to your lungs, gets cleaned up with fresh oxygen, then returns to your left atrium via pulmonary veins.
The systemic circuit delivers the goods to your body. Oxygenated blood shoots out from your left ventricle through the massive aorta, travels to all your muscles and organs, then returns as deoxygenated blood through the vena cava to your right atrium. It's like a perfectly timed relay race that never stops!
Quick Tip: Remember the circuits by thinking "Right = Respiratory" (pulmonary circuit starts from right side) and "Left = Life" (systemic circuit starts from left side to supply your whole body).
Think of blood vessels as a three-tier transport system, each designed for different jobs. Arteries are like motorways - they've got thick, muscular walls and narrow lumens because they handle high-pressure blood rushing away from your heart. Most carry oxygenated blood, except for those sneaky pulmonary arteries heading to your lungs.
Veins are more like country roads - they have thinner walls, wider lumens, and special valves to prevent blood from flowing backwards as it travels back to your heart under much lower pressure. Capillaries are the tiny back streets where all the real action happens - their walls are just one cell thick, allowing oxygen and nutrients to slip through to your tissues.
Each type of vessel is perfectly designed for its job. The thick, elastic artery walls can stretch and bounce back with each heartbeat, whilst the wide vein lumens make it easier for blood to flow back to your heart against gravity.
Your blood is like a busy transport network with different workers doing specific jobs. Red blood cells are the oxygen delivery drivers - they pick up oxygen from your lungs and drop it off at your muscles, then collect carbon dioxide waste for the return journey.
White blood cells act as your personal security team, fighting off infections and diseases that try to invade your body. Platelets are like emergency repair workers - when you get a cut, they rush to the scene and help your blood clot to stop the bleeding.
All these cells float around in plasma, which is basically the liquid motorway that carries everything through your bloodstream. Plasma also transports nutrients, hormones, and waste products around your body, making it essential for keeping everything running smoothly.
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.
You can download the app in the Google Play Store and in the Apple App Store.
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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Explore the key functions and components of the cardiovascular and respiratory systems, including blood circulation, gas exchange, and their roles in sports performance. This summary covers essential concepts such as heart anatomy, blood pressure, and the importance of red blood cells, providing a comprehensive understanding for students in human anatomy and physiology.
Physical EducationExplore the intricacies of the cardiovascular system, including the structure and function of the heart, blood vessels, and the processes of vasoconstriction and vasodilation. This summary covers key concepts such as the double circulatory system, cardiac output, and the role of hemoglobin in oxygen transport. Ideal for students studying biology and human anatomy.
PEExplore the key differences between aerobic and anaerobic exercise, including their energy systems, training methods, and benefits for cardiovascular health. This summary covers essential concepts in exercise physiology and physical education, highlighting effective training strategies such as HIIT, interval training, and continuous workouts.
Physical EducationExplore the essential components and functions of the cardiovascular system, including the heart's structure, the double-circulatory system, and the roles of arteries, veins, and capillaries. This summary is tailored for OCR GCSE PE students, highlighting key concepts such as heart rate, stroke volume, and cardiac output.
Physical EducationExplore the key functions of the cardiovascular and respiratory systems, including blood circulation, gas exchange, and the mechanics of breathing. This summary covers arteries, veins, capillaries, cardiac output, and the pathway of air during inspiration, providing essential insights for understanding human physiology.
PEExplore the key components of the skeletal system, including bone types, joint structures, and their functions in movement and protection. This summary covers the roles of bones in blood cell production, mineral storage, and muscle attachment, along with detailed descriptions of various joint types and their movements. Ideal for students studying human anatomy and physiology.
PEApp Store
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
