Živčni sistem je kot internet tvojega telesa - omogoča komunikacijo... Show more
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Updated May 2, 2026
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Živčni sistem - Kako deluje?
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Pregled živčnega sistema
Predstavljaj si živčni sistem kot super napreden komunikacijski center, ki deluje 24/7. Nevron je osnovna enota - to je tista celica, ki prenaša sporočila po telesu kot električni signali.
Vsak nevron ima telo celice (kjer je jedro), dendrite (ki sprejemajo signale od drugih nevronov) in akson (dolg kabel, ki pošlje signal naprej). Okoli aksona je mielinska ovojnica - to je kot izolacija na električnem kablu, ki pohitri prenos.
Glia celice so kot vzdrževalci - skrbijo za nevrone, jih hranijo in čistijo za njimi. Sinapsa pa je mesto, kjer se nevron "pogovarja" z drugim nevronom preko kemičnih sporočil - nevrotransmiterjev.
💡 Zanimivo: V možganih imaš več nevronov kot zvezd v naši galaksiji!
Mirovni potencial in začetek impulza
Ko nevron ni aktiven, je kot baterija z mirovnim potencialom -70 mV. To pomeni, da je znotraj negativno naelektren glede na zunanjost. Za to skrbi natrij-kalijeva črpalka, ki kot neutrudna črpalka vedno črpa 3 Na⁺ ione ven in 2 K⁺ iona noter.
Mielinska ovojnica ni kontinuirana - ima Ranvierove zažetke (vrzeli), kjer impulz "preskakuje" kot žaba med listi. To je saltatorni prenos - veliko hitrejši od kontinuiranega.
Membrana je v mirovanju bolj prepustna za K⁺, ki uhajajo ven in ohranjajo negativen naboj znotraj celice. Ta sistem je kot pripravljenost - čaka na pravi signal za akcijo.
💡 Pomni: Mirovni potencial = -70 mV = nevron pripravljen na akcijo!
Akcijski potencial - živčni impulz
Ko dražljaj doseže prag vzdražnosti , se zgodi prava predstava! Akcijski potencial deluje po principu "vse-ali-nič" - ali se sproži popolnoma (vedno enako močno) ali pa se sploh ne.
Depolarizacija: Na⁺ kanalčki se odprejo kot povodje, natrij vdira noter in napetost skoči na +30 mV. Repolarizacija: Na⁺ kanalčki se zaprejo, K⁺ kanalčki se odprejo in kalij beži ven, vračajoč negativen naboj. Hiperpolarizacija: K⁺ kanalčki se zapirajo počasi, zato za hip pade napetost pod -70 mV.
Moč dražljaja se ne kaže v velikosti impulza (vedno je enak), ampak v frekvenci - močnejši dražljaj = več impulzov na sekundo.
💡 Za test: Depolarizacija = Na⁺ noter, repolarizacija = K⁺ ven!
Sinaptični prenos in delitev sistema
Ko akcijski potencial doseže konec aksona, se sproži kemična reakcja. Ca²⁺ ioni vdrejo noter in sprožijo sproščanje nevrotransmiterjev (kot so acetilholin, dopamin) v sinaptično špranjo. Ti se povežejo z receptorji na naslednji celici in jo bodisi vzbudijo ali zavrejo.
Centralni živčni sistem (CŽS) = možgani + hrbtenjača = "glavni računalnik". Periferni živčni sistem (PŽS) = vsi ostali živci = "kabli in povezave".
Avtonomni sistem dela samodejno: simpatik te pripravi na akcijo ("boj ali beg"), parasimpatik te umiri ("počitek in prebava"). Delujeta nasprotno - kot plin in zavora v avtu.
Refleksni lok omogoča hitre odzive brez možganov - signal gre do hrbtenjače in nazaj k mišici. Zato tako hitro odtrgnеš roko od vroče plošče!
💡 Ključno: Simpatik = akcija, parasimpatik = umiritev. Zapomnisi: "Simpati'K' = 'K'onflikt"!
Hitri pregled za test
Mielinska ovojnica je ključna za hitrost - pri multipli sklerozi se uničuje, zato so gibi počasni. Droge in strupi pogosto delujejo na sinapse - bodisi posnemajo nevrotransmiterje ali blokirajo receptorje.
Zapomni si osnovne številke: mirovni potencial -70 mV, prag -55 mV, vrh akcijskega potenciala +30 mV. Na⁺/K⁺ črpalka deluje v razmerju 3:2.
Za ponavljanje: nevron ima telo-dendrite-akson, impulz deluje "vse-ali-nič", sinapse uporabljajo nevrotransmiterje, CŽS nadzoruje, PŽS povezuje, avtonomni sistem dela samodejno.
Če razumeš, kako se ioni gibljejo preko membrane , imaš že polovico snovi obvladane!
💡 Pro tip: Narišի si graf akcijskega potenciala - vizualno pomnjenje je najmočnejše!
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
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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
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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
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Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
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
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Živčni sistem - Kako deluje?
Živčni sistem je kot internet tvojega telesa - omogoča komunikacijo med vsemi deli in nadzoruje vse, kar se dogaja v tebi. Skupaj s hormoni skrbi, da vse deluje kot po maslu, od zaznavanje okolice do gibanja mišic.
Pregled živčnega sistema
Predstavljaj si živčni sistem kot super napreden komunikacijski center, ki deluje 24/7. Nevron je osnovna enota - to je tista celica, ki prenaša sporočila po telesu kot električni signali.
Vsak nevron ima telo celice (kjer je jedro), dendrite (ki sprejemajo signale od drugih nevronov) in akson (dolg kabel, ki pošlje signal naprej). Okoli aksona je mielinska ovojnica - to je kot izolacija na električnem kablu, ki pohitri prenos.
Glia celice so kot vzdrževalci - skrbijo za nevrone, jih hranijo in čistijo za njimi. Sinapsa pa je mesto, kjer se nevron "pogovarja" z drugim nevronom preko kemičnih sporočil - nevrotransmiterjev.
💡 Zanimivo: V možganih imaš več nevronov kot zvezd v naši galaksiji!
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Mirovni potencial in začetek impulza
Ko nevron ni aktiven, je kot baterija z mirovnim potencialom -70 mV. To pomeni, da je znotraj negativno naelektren glede na zunanjost. Za to skrbi natrij-kalijeva črpalka, ki kot neutrudna črpalka vedno črpa 3 Na⁺ ione ven in 2 K⁺ iona noter.
Mielinska ovojnica ni kontinuirana - ima Ranvierove zažetke (vrzeli), kjer impulz "preskakuje" kot žaba med listi. To je saltatorni prenos - veliko hitrejši od kontinuiranega.
Membrana je v mirovanju bolj prepustna za K⁺, ki uhajajo ven in ohranjajo negativen naboj znotraj celice. Ta sistem je kot pripravljenost - čaka na pravi signal za akcijo.
💡 Pomni: Mirovni potencial = -70 mV = nevron pripravljen na akcijo!
Sign up to see the contentIt's free!
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Akcijski potencial - živčni impulz
Ko dražljaj doseže prag vzdražnosti , se zgodi prava predstava! Akcijski potencial deluje po principu "vse-ali-nič" - ali se sproži popolnoma (vedno enako močno) ali pa se sploh ne.
Depolarizacija: Na⁺ kanalčki se odprejo kot povodje, natrij vdira noter in napetost skoči na +30 mV. Repolarizacija: Na⁺ kanalčki se zaprejo, K⁺ kanalčki se odprejo in kalij beži ven, vračajoč negativen naboj. Hiperpolarizacija: K⁺ kanalčki se zapirajo počasi, zato za hip pade napetost pod -70 mV.
Moč dražljaja se ne kaže v velikosti impulza (vedno je enak), ampak v frekvenci - močnejši dražljaj = več impulzov na sekundo.
💡 Za test: Depolarizacija = Na⁺ noter, repolarizacija = K⁺ ven!
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Sinaptični prenos in delitev sistema
Ko akcijski potencial doseže konec aksona, se sproži kemična reakcja. Ca²⁺ ioni vdrejo noter in sprožijo sproščanje nevrotransmiterjev (kot so acetilholin, dopamin) v sinaptično špranjo. Ti se povežejo z receptorji na naslednji celici in jo bodisi vzbudijo ali zavrejo.
Centralni živčni sistem (CŽS) = možgani + hrbtenjača = "glavni računalnik". Periferni živčni sistem (PŽS) = vsi ostali živci = "kabli in povezave".
Avtonomni sistem dela samodejno: simpatik te pripravi na akcijo ("boj ali beg"), parasimpatik te umiri ("počitek in prebava"). Delujeta nasprotno - kot plin in zavora v avtu.
Refleksni lok omogoča hitre odzive brez možganov - signal gre do hrbtenjače in nazaj k mišici. Zato tako hitro odtrgnеš roko od vroče plošče!
💡 Ključno: Simpatik = akcija, parasimpatik = umiritev. Zapomnisi: "Simpati'K' = 'K'onflikt"!
Sign up to see the contentIt's free!
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Hitri pregled za test
Mielinska ovojnica je ključna za hitrost - pri multipli sklerozi se uničuje, zato so gibi počasni. Droge in strupi pogosto delujejo na sinapse - bodisi posnemajo nevrotransmiterje ali blokirajo receptorje.
Zapomni si osnovne številke: mirovni potencial -70 mV, prag -55 mV, vrh akcijskega potenciala +30 mV. Na⁺/K⁺ črpalka deluje v razmerju 3:2.
Za ponavljanje: nevron ima telo-dendrite-akson, impulz deluje "vse-ali-nič", sinapse uporabljajo nevrotransmiterje, CŽS nadzoruje, PŽS povezuje, avtonomni sistem dela samodejno.
Če razumeš, kako se ioni gibljejo preko membrane , imaš že polovico snovi obvladane!
💡 Pro tip: Narišի si graf akcijskega potenciala - vizualno pomnjenje je najmočnejše!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and 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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Students love us — and so will you.
4.6/5
App Store
4.7/5
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
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
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
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user