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Biology
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AP Chemistry
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Cecilya Guilbault
12/11/2025
Health
Anatomy and Physiology Notes
100
•
Dec 11, 2025
•
The integumentary system is your body's protective outer layer, including... Show more
Your skin is more complex than it appears! It contains four main tissues (epithelial, connective, smooth muscle, and nervous) working together to protect you, help you feel sensations, regulate body temperature, and even synthesize important compounds.
The epidermis, your skin's outer layer, is constantly renewing itself in a 28-day cycle. It's thicker on your palms and soles where you need extra protection. This layer is organized from bottom to top as: Stratum Germinativum, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, and finally Stratum Corneum.
Vitiligo is a pigmentation disorder where melanocytes are destroyed, creating distinctive light patches on the skin and mucous membranes. You might even notice affected hair turning white as pigment disappears.
Fun Fact: Every month, you essentially get a completely new outer layer of skin as old cells are shed and replaced by new ones from below!
The Stratum Germinativum is your skin's powerhouse - it's the deepest layer where stem cells actively divide. These new cells gradually push upward through the layers. Interestingly, this layer contains melanocytes that produce the pigment giving your skin its color.
As cells move up through the intermediate strata, they begin producing keratin - an incredibly strong protein that makes your skin water-resistant and durable. Keratin doesn't just protect your skin; it's the same protein that forms your hair, nails, calluses, and even animal features like horns and hooves!
By the time cells reach the Stratum Lucidum and Corneum, they're actually dead and ready to be shed. While some sun exposure (about 10 minutes daily) is beneficial, prolonged UV radiation can lead to premature wrinkles and various forms of skin cancer.
Remember: Your skin color comes from two main pigments - melanin (produced by melanocytes and influenced by genetics and sun exposure) and carotene .
Your skin's appearance can change rapidly through dermal circulation - when blood vessels dilate, you blush, and when they constrict, you look pale. This is particularly visible in areas like your lips, nails, and ears.
Skin cancer develops when skin cells grow abnormally. There are two main categories: benign tumors (which don't spread) and malignant cancers (which can spread throughout the body). The three primary types of skin cancer include basal cell carcinoma (most common but least dangerous), squamous cell carcinoma (needs early removal), and malignant melanoma (the most deadly form).
For melanoma detection, remember the ABCD rule: check for Asymmetry, Border irregularity, Color variations, and Diameter larger than a pencil eraser. This simple check could literally save your life!
Important: Early detection of skin cancer dramatically improves treatment success rates, so regularly examine your skin for changes and protect yourself from excessive UV exposure.
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
The integumentary system is your body's protective outer layer, including skin, hair, nails, and various glands. This remarkable system not only shields your body but also helps regulate temperature, store chemicals, and even excrete waste. Understanding how this system works... Show more
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Your skin is more complex than it appears! It contains four main tissues (epithelial, connective, smooth muscle, and nervous) working together to protect you, help you feel sensations, regulate body temperature, and even synthesize important compounds.
The epidermis, your skin's outer layer, is constantly renewing itself in a 28-day cycle. It's thicker on your palms and soles where you need extra protection. This layer is organized from bottom to top as: Stratum Germinativum, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, and finally Stratum Corneum.
Vitiligo is a pigmentation disorder where melanocytes are destroyed, creating distinctive light patches on the skin and mucous membranes. You might even notice affected hair turning white as pigment disappears.
Fun Fact: Every month, you essentially get a completely new outer layer of skin as old cells are shed and replaced by new ones from below!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The Stratum Germinativum is your skin's powerhouse - it's the deepest layer where stem cells actively divide. These new cells gradually push upward through the layers. Interestingly, this layer contains melanocytes that produce the pigment giving your skin its color.
As cells move up through the intermediate strata, they begin producing keratin - an incredibly strong protein that makes your skin water-resistant and durable. Keratin doesn't just protect your skin; it's the same protein that forms your hair, nails, calluses, and even animal features like horns and hooves!
By the time cells reach the Stratum Lucidum and Corneum, they're actually dead and ready to be shed. While some sun exposure (about 10 minutes daily) is beneficial, prolonged UV radiation can lead to premature wrinkles and various forms of skin cancer.
Remember: Your skin color comes from two main pigments - melanin (produced by melanocytes and influenced by genetics and sun exposure) and carotene .
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your skin's appearance can change rapidly through dermal circulation - when blood vessels dilate, you blush, and when they constrict, you look pale. This is particularly visible in areas like your lips, nails, and ears.
Skin cancer develops when skin cells grow abnormally. There are two main categories: benign tumors (which don't spread) and malignant cancers (which can spread throughout the body). The three primary types of skin cancer include basal cell carcinoma (most common but least dangerous), squamous cell carcinoma (needs early removal), and malignant melanoma (the most deadly form).
For melanoma detection, remember the ABCD rule: check for Asymmetry, Border irregularity, Color variations, and Diameter larger than a pencil eraser. This simple check could literally save your life!
Important: Early detection of skin cancer dramatically improves treatment success rates, so regularly examine your skin for changes and protect yourself from excessive UV exposure.
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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Unit 6: The Human Body Module 22: Integumentary, Skeletal, and Muscular Systems Lesson 2: The Skeletal System Lesson 3: The Muscular System Biology 9A
BiologyNotes describing different bacteria types and their effects
BiologyFor the IB Biology course
BiologyDiscussion on how life is organized.
BiologyExplore the classification of living organisms, including vertebrates and invertebrates. This summary covers key groups such as mammals, birds, reptiles, amphibians, and various invertebrate categories like arthropods and molluscs. Understand the characteristics that define each group and their relationships within the biological classification system.
BiologyDiscussed here are the characteristics of living things, big ideas in biology, information and heredity, and unity and diversity of life.
BiologyApp 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
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