Anatomy and Physiology is the study of how our bodies... Show more
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Dec 8, 2025
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Understanding Anatomy and Physiology Fundamentals
Kylie Zaleski
@kylie_zaleski
1 / 5
Introduction to Anatomy & Physiology
Anatomy refers to the structure of body parts and how they're organized within the body. Physiology focuses on what these parts actually do and how they perform their functions. The key relationship to remember is that structure equals function—how a body part is built determines what it can do.
Think of your body like a complex machine where every part has a specific design for a specific purpose. Your fingers are jointed to allow gripping, while your heart has chambers and valves to pump blood efficiently.
Metabolism encompasses all the physical and chemical reactions that produce energy in your body. This includes ingesting food, breaking it down, absorbing nutrients, and circulating them throughout your body.
💡 Fun fact: An adult human body contains around 37 trillion cells, each with specific structures that allow them to perform their unique functions!
Homeostasis: Maintaining Balance
Homeostasis is your body's remarkable ability to maintain a stable internal environment despite changing external conditions. This balance is crucial because your body can only function properly within certain limits of temperature, pH, and other factors.
Your body uses sophisticated mechanisms to maintain homeostasis:
- Receptors detect changes and provide information about stimuli
- Set points or control centers determine how far conditions have deviated from normal
- Effectors produce responses that bring conditions back to normal
There are two main feedback mechanisms: Negative feedback works to return conditions to normal (like a thermostat), while positive feedback amplifies changes away from normal (like during childbirth).
⚠️ When homeostasis fails, illness occurs. Many diseases are essentially failures of homeostatic mechanisms!
Organization of the Body
Your body is organized into two main portions: the axial portion (head, neck, and trunk) and the appendicular portion (arms and legs). This division helps us understand how different body regions relate to each other.
The axial portion contains two major body cavities. The dorsal cavity includes the cranial cavity (housing your brain) and the vertebral canal (containing your spinal cord). The ventral cavity contains your organs or viscera.
The ventral cavity is further divided into the thoracic and abdominopelvic cavities, which are separated by the muscular diaphragm. This organization protects vital organs and groups them according to their functions.
💡 The term "viscera" refers to internal organs within the body cavities, especially those in the abdomen like the stomach, intestines, and liver.
Body Cavities and Membranes
The thoracic cavity (chest) contains vital organs and is divided by the mediastinum, which creates left and right compartments. The mediastinum houses the heart, while the pleural cavities on either side contain the lungs.
Below the diaphragm lies the abdominopelvic cavity, which is divided into upper and lower regions. The abdominal region contains digestive organs like the liver and stomach, while the pelvic region houses reproductive organs.
Special membranes line these cavities to protect organs. These include parietal membranes (lining the cavity walls) and visceral membranes (covering the organs themselves). Between these membranes is serous fluid, a watery substance that reduces friction as organs move and function.
🔍 Notice how your body uses fluid-filled spaces to protect organs—similar to how a car uses oil to prevent engine parts from damaging each other through friction!
Specialized Membranes
The lungs are covered by a membrane called the visceral pleura, which directly contacts the lung surface. The cavity itself is lined with parietal pleura. These two layers of pleura slide against each other smoothly thanks to serous fluid between them.
The heart has its own protective membrane called the pericardium. Like the pleura, the pericardium has parietal and visceral layers with fluid between them that allows your heart to beat without friction.
These specialized membrane systems demonstrate how the body uses similar structural solutions to solve similar problems (reducing friction) in different organs.
💡 When these membranes become inflamed (pleuritis or pericarditis), the result is often sharp pain during movement because the normally smooth surfaces become rough and irritated.
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.
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
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 Anatomy and Physiology Fundamentals
Kylie Zaleski
@kylie_zaleski
Anatomy and Physiology is the study of how our bodies are structured and function. This field explores both what our body parts look like and how they work together to keep us alive. Understanding these concepts is essential for anyone... Show more
Introduction to Anatomy & Physiology
Anatomy refers to the structure of body parts and how they're organized within the body. Physiology focuses on what these parts actually do and how they perform their functions. The key relationship to remember is that structure equals function—how a body part is built determines what it can do.
Think of your body like a complex machine where every part has a specific design for a specific purpose. Your fingers are jointed to allow gripping, while your heart has chambers and valves to pump blood efficiently.
Metabolism encompasses all the physical and chemical reactions that produce energy in your body. This includes ingesting food, breaking it down, absorbing nutrients, and circulating them throughout your body.
💡 Fun fact: An adult human body contains around 37 trillion cells, each with specific structures that allow them to perform their unique functions!
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
Homeostasis: Maintaining Balance
Homeostasis is your body's remarkable ability to maintain a stable internal environment despite changing external conditions. This balance is crucial because your body can only function properly within certain limits of temperature, pH, and other factors.
Your body uses sophisticated mechanisms to maintain homeostasis:
- Receptors detect changes and provide information about stimuli
- Set points or control centers determine how far conditions have deviated from normal
- Effectors produce responses that bring conditions back to normal
There are two main feedback mechanisms: Negative feedback works to return conditions to normal (like a thermostat), while positive feedback amplifies changes away from normal (like during childbirth).
⚠️ When homeostasis fails, illness occurs. Many diseases are essentially failures of homeostatic mechanisms!
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
Organization of the Body
Your body is organized into two main portions: the axial portion (head, neck, and trunk) and the appendicular portion (arms and legs). This division helps us understand how different body regions relate to each other.
The axial portion contains two major body cavities. The dorsal cavity includes the cranial cavity (housing your brain) and the vertebral canal (containing your spinal cord). The ventral cavity contains your organs or viscera.
The ventral cavity is further divided into the thoracic and abdominopelvic cavities, which are separated by the muscular diaphragm. This organization protects vital organs and groups them according to their functions.
💡 The term "viscera" refers to internal organs within the body cavities, especially those in the abdomen like the stomach, intestines, and liver.
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
Body Cavities and Membranes
The thoracic cavity (chest) contains vital organs and is divided by the mediastinum, which creates left and right compartments. The mediastinum houses the heart, while the pleural cavities on either side contain the lungs.
Below the diaphragm lies the abdominopelvic cavity, which is divided into upper and lower regions. The abdominal region contains digestive organs like the liver and stomach, while the pelvic region houses reproductive organs.
Special membranes line these cavities to protect organs. These include parietal membranes (lining the cavity walls) and visceral membranes (covering the organs themselves). Between these membranes is serous fluid, a watery substance that reduces friction as organs move and function.
🔍 Notice how your body uses fluid-filled spaces to protect organs—similar to how a car uses oil to prevent engine parts from damaging each other through friction!
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
Specialized Membranes
The lungs are covered by a membrane called the visceral pleura, which directly contacts the lung surface. The cavity itself is lined with parietal pleura. These two layers of pleura slide against each other smoothly thanks to serous fluid between them.
The heart has its own protective membrane called the pericardium. Like the pleura, the pericardium has parietal and visceral layers with fluid between them that allows your heart to beat without friction.
These specialized membrane systems demonstrate how the body uses similar structural solutions to solve similar problems (reducing friction) in different organs.
💡 When these membranes become inflamed (pleuritis or pericarditis), the result is often sharp pain during movement because the normally smooth surfaces become rough and irritated.
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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4.9/5
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
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