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Leticia Siburian
11/28/2025
AP Psychology
AP Psych unit 2
23
•
Nov 28, 2025
•
Leticia Siburian
@leticiasbrn29
The nervous system is your body's command center, coordinating everything... Show more
Ever wonder why you might act like your parents? Behavioral geneticists study how genes and environment shape who we are. Twin and adoption studies are particularly revealing—identical twins share the same genes but not identical copies, making them perfect for studying nature versus nurture influences.
Your body's communication networks are fascinating! The endocrine system works through glands that release hormones into your bloodstream. Unlike the lightning-fast nervous system, hormones work more slowly but have longer-lasting effects. Key players include the pituitary gland (releasing growth hormone and oxytocin for bonding), adrenal glands , and the pancreas (regulating blood sugar).
The nervous system is your body's electrochemical messaging network. It divides into the Central Nervous System (brain and spinal cord) and Peripheral Nervous System (everything else). When you touch something hot, a reflex kicks in—your spinal cord processes this information and sends a response before your brain even registers what happened!
Did you know? The autonomic nervous system has two opposing branches: the sympathetic system gets you pumped up for action, while the parasympathetic system calms you back down—like having both an accelerator and brakes for your body!
Neurons are the superheroes of your nervous system! These specialized cells relay messages throughout your body. Each neuron has dendrites that receive information, a cell body that processes it, and an axon that sends the message onward. The axon is often covered with a myelin sheath that speeds up transmission—like adding a turbo boost to your neural messages.
For a message to travel, the neuron must reach its threshold to trigger an action potential. This works on an all-or-none principle—either the message fires completely or not at all. Think of it as flipping a light switch—there's no halfway on!
Your brain uses chemical messengers called neurotransmitters to communicate between neurons. Some are excitatory (like pushing an accelerator), while others are inhibitory (like hitting the brakes). Each neurotransmitter has specific functions: acetylcholine enables muscle action and memory, dopamine influences movement and emotion, and serotonin affects mood and sleep.
Brain Chemistry Alert: Many drugs affect your neurotransmitters—depressants like alcohol slow neural activity, stimulants like caffeine speed things up, and hallucinogens like LSD distort perceptions. Understanding these effects helps explain why substances alter your thoughts and behaviors so dramatically!
Your brain is like the world's most complex command center! The brainstem handles basic survival functions—the medulla controls heart rate and breathing, while the cerebellum coordinates movement and balance. These structures evolved first and are found in many animals.
Moving inward, the limbic system is your emotional headquarters. The amygdala processes emotions (especially fear), the hypothalamus maintains your body's balance, and the hippocampus forms explicit memories. When you remember your first day of school or feel nervous before a test, you're experiencing your limbic system at work!
The outer layer—your cerebral cortex—is where higher thinking happens. Different lobes handle specific functions: frontal lobes for decision-making, parietal lobes for touch sensations, occipital lobes for vision, and temporal lobes for hearing. The corpus callosum connects your brain's left hemisphere (analytical) with your right hemisphere (creative).
Mind Blown: Scientists can now see your brain in action! EEG and PET scans show activity patterns, while CT scans and MRIs reveal physical structures. These technologies help us understand how thinking happens and what goes wrong in brain disorders.
Your brain is incredibly adaptable! Neuroplasticity is your brain's remarkable ability to reorganize itself—creating new connections and even growing new neurons (neurogenesis). This is how you learn new skills and recover from brain injuries. Your brain is constantly reshaping itself based on your experiences.
Ever feel sleepy around the same time each night? That's your circadian rhythm—your body's internal clock. The pineal gland produces melatonin when it gets dark, signaling that it's time to sleep. This rhythm helps coordinate your body's functions with the 24-hour day.
Sleep isn't just rest—it's critical for your brain! As you cycle through sleep stages, different brain waves dominate. Light sleep features theta waves and possible hallucinations. NREM-2 includes sleep spindles that help with memory. Deep sleep shows delta waves and releases growth hormones. Finally, REM sleep brings vivid dreams while your body is paralyzed—protecting you from acting out those dreams!
Sleep Science: Dreams aren't just random stories! Some psychologists distinguish between the manifest content (the actual dream story) and latent content (hidden meanings). Whether dreams help process emotions or are just neural noise, they're a fascinating window into your sleeping mind.
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
Leticia Siburian
@leticiasbrn29
The nervous system is your body's command center, coordinating everything from your heartbeat to your thoughts. This guide breaks down how genes, hormones, neurons, and brain structures work together to control your behavior, emotions, and bodily functions—essential knowledge that helps... Show more
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Improve your grades
Join milions of students
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Ever wonder why you might act like your parents? Behavioral geneticists study how genes and environment shape who we are. Twin and adoption studies are particularly revealing—identical twins share the same genes but not identical copies, making them perfect for studying nature versus nurture influences.
Your body's communication networks are fascinating! The endocrine system works through glands that release hormones into your bloodstream. Unlike the lightning-fast nervous system, hormones work more slowly but have longer-lasting effects. Key players include the pituitary gland (releasing growth hormone and oxytocin for bonding), adrenal glands , and the pancreas (regulating blood sugar).
The nervous system is your body's electrochemical messaging network. It divides into the Central Nervous System (brain and spinal cord) and Peripheral Nervous System (everything else). When you touch something hot, a reflex kicks in—your spinal cord processes this information and sends a response before your brain even registers what happened!
Did you know? The autonomic nervous system has two opposing branches: the sympathetic system gets you pumped up for action, while the parasympathetic system calms you back down—like having both an accelerator and brakes for your body!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Neurons are the superheroes of your nervous system! These specialized cells relay messages throughout your body. Each neuron has dendrites that receive information, a cell body that processes it, and an axon that sends the message onward. The axon is often covered with a myelin sheath that speeds up transmission—like adding a turbo boost to your neural messages.
For a message to travel, the neuron must reach its threshold to trigger an action potential. This works on an all-or-none principle—either the message fires completely or not at all. Think of it as flipping a light switch—there's no halfway on!
Your brain uses chemical messengers called neurotransmitters to communicate between neurons. Some are excitatory (like pushing an accelerator), while others are inhibitory (like hitting the brakes). Each neurotransmitter has specific functions: acetylcholine enables muscle action and memory, dopamine influences movement and emotion, and serotonin affects mood and sleep.
Brain Chemistry Alert: Many drugs affect your neurotransmitters—depressants like alcohol slow neural activity, stimulants like caffeine speed things up, and hallucinogens like LSD distort perceptions. Understanding these effects helps explain why substances alter your thoughts and behaviors so dramatically!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your brain is like the world's most complex command center! The brainstem handles basic survival functions—the medulla controls heart rate and breathing, while the cerebellum coordinates movement and balance. These structures evolved first and are found in many animals.
Moving inward, the limbic system is your emotional headquarters. The amygdala processes emotions (especially fear), the hypothalamus maintains your body's balance, and the hippocampus forms explicit memories. When you remember your first day of school or feel nervous before a test, you're experiencing your limbic system at work!
The outer layer—your cerebral cortex—is where higher thinking happens. Different lobes handle specific functions: frontal lobes for decision-making, parietal lobes for touch sensations, occipital lobes for vision, and temporal lobes for hearing. The corpus callosum connects your brain's left hemisphere (analytical) with your right hemisphere (creative).
Mind Blown: Scientists can now see your brain in action! EEG and PET scans show activity patterns, while CT scans and MRIs reveal physical structures. These technologies help us understand how thinking happens and what goes wrong in brain disorders.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your brain is incredibly adaptable! Neuroplasticity is your brain's remarkable ability to reorganize itself—creating new connections and even growing new neurons (neurogenesis). This is how you learn new skills and recover from brain injuries. Your brain is constantly reshaping itself based on your experiences.
Ever feel sleepy around the same time each night? That's your circadian rhythm—your body's internal clock. The pineal gland produces melatonin when it gets dark, signaling that it's time to sleep. This rhythm helps coordinate your body's functions with the 24-hour day.
Sleep isn't just rest—it's critical for your brain! As you cycle through sleep stages, different brain waves dominate. Light sleep features theta waves and possible hallucinations. NREM-2 includes sleep spindles that help with memory. Deep sleep shows delta waves and releases growth hormones. Finally, REM sleep brings vivid dreams while your body is paralyzed—protecting you from acting out those dreams!
Sleep Science: Dreams aren't just random stories! Some psychologists distinguish between the manifest content (the actual dream story) and latent content (hidden meanings). Whether dreams help process emotions or are just neural noise, they're a fascinating window into your sleeping mind.
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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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
