Human Brain and Nervous System: Complete NCERT Notes in Hinglish
Nervous System Kya Hai? (What is the Nervous System?)
Nervous system body ka "control and communication system" hai. Yeh environment se information collect karta hai, usse process karta hai, aur body ko response dene ka order deta hai. Jaise ek super-fast computer, yeh body ke har function ko coordinate karta hai.
Nervous System Ke 2 Main Parts:
Central Nervous System (CNS): Brain aur Spinal Cord.
Peripheral Nervous System (PNS): Body ke baaki nerves jo CNS se connect hote hain.
Example: Jab tum garam cheez chhute ho, nervous system turant signal bhejta hai haath hataane ke liye.
1. Central Nervous System (CNS)
CNS body ka main control center hai, jo brain aur spinal cord se bana hai.
A. Human Brain
Brain nervous system ka boss hai. Yeh thoughts, memory, emotions, aur body ke functions (jaise breathing, walking) ko control karta hai. Iska weight ~1.4 kg hota hai, aur yeh billions of neurons se bana hai.
Brain Ke Main Parts aur Unke Kaam
Cerebrum (Bada Dimaag)
Sabse bada part, divided into 2 hemispheres (left aur right).
Kaam: Thinking, memory, reasoning, decision-making, aur voluntary actions (jo hum apni marzi se karte hain).
4 Lobes:
Frontal Lobe: Planning, problem-solving, emotions.
Example: Exam ke liye timetable banana frontal lobe ka kaam hai.
Parietal Lobe: Touch, pain, temperature sense.
Example: Thandi hawa lagti hai toh usse feel karna parietal lobe karta hai.
Temporal Lobe: Hearing, memory, language.
Example: Favorite song sunna ya lyrics yaad rakhna temporal lobe ka kaam hai.
Occipital Lobe: Vision (dekhna).
Example: TV pe cartoon ke colors dekhna occipital lobe process karta hai.
Cerebellum (Chhota Dimaag)
Brain ke peeche hota hai.
Kaam: Balance, posture, aur coordination of movements.
Example: Cycle chalate waqt balance rakhna ya dance ke steps karna cerebellum ke wajah se hota hai.
Brain Stem (Dimaag ka Base)
Brain ko spinal cord se connect karta hai.
Kaam: Basic life functions jaise breathing, heartbeat, digestion, aur sleeping.
Example: Tum so rahe ho, par dil dhadak raha hai – yeh brain stem control karta hai.
Brain Ki Protection
Cranium (Skull): Brain ko hard bone se protect karta hai.
Meninges: Teen layers ki membrane jo brain ko cover karti hai.
Cerebrospinal Fluid (CSF): Brain ke liye cushion ka kaam karta hai, shocks absorb karta hai.
Example: Jab tum girte ho, CSF brain ko chot se bachata hai.
B. Spinal Cord
Yeh ek long, cylindrical structure hai jo brain se niche back ke andar hota hai.
Kaam:
Brain aur body ke beech signals carry karta hai.
Reflex actions ko control karta hai.
Example: Jab doctor hammer se knee pe maarta hai aur pair upar jata hai, yeh spinal cord ka reflex action hai.
Protection: Spinal cord vertebrae (backbone) aur CSF se protected hota hai.
2. Peripheral Nervous System (PNS)
PNS mein body ke nerves hote hain jo CNS (brain aur spinal cord) ko body ke baaki parts se connect karte hain.
PNS Ke 2 Types:
Somatic Nervous System: Voluntary actions (jo hum apni marzi se karte hain) ko control karta hai.
Example: Haath uthana, chalna, ya likhna – yeh somatic nervous system ke signals se hota hai.
Autonomic Nervous System: Involuntary actions (jo apne aap hote hain) ko control karta hai.
2 Sub-types:
Sympathetic: Emergency situations mein body ko ready karta hai (fight or flight).
Example: Kutta peeche bhagta hai toh heart rate badh jata hai – yeh sympathetic system ka kaam hai.
Parasympathetic: Body ko relax karta hai (rest and digest).
Example: Khana khane ke baad digestion smoothly hota hai – yeh parasympathetic system karta hai.
3. Neurons: Nervous System ka Building Block
Neurons nerve cells hain jo signals transmit karte hain. Yeh nervous system ka core hain.
Neuron Ka Structure
Dendrites: Signals receive karte hain.
Cell Body (Soma): Signal ko process karta hai.
Axon: Signal ko aage bhejta hai.
Synapse: Gap jahan ek neuron doosre neuron se signal pass karta hai via neurotransmitters (chemicals jaise dopamine).
Example: Jab tum pen pakadte ho, neurons signal bhejte hain muscles ko pen pakadne ke liye.
Types of Neurons
Sensory Neurons: Body se brain tak sensory information (touch, sound) le jate hain.
Example: Thandi cheez chhune ka signal brain tak jata hai.
Motor Neurons: Brain se muscles tak signals le jate hain for movement.
Example: Haath se ball fekna motor neurons ke wajah se hota hai.
Interneurons: Sensory aur motor neurons ke beech connection banate hain.
Example: Garam cheez chhune pe reflex action interneurons ke through hota hai.
Neuron Ka Kaam
Signals receive, process, aur transmit karna.
Synapse ke through chemical signals (neurotransmitters) bhejna.
Example: Jab tum question ka answer sochte ho, neurons ek doosre se signals bhejte hain jawab yaad karne ke liye.
4. Reflex Action
Reflex action ek quick, automatic response hai jo spinal cord control karta hai, brain ke involvement ke bina. Yeh body ko danger se bachane ke liye hota hai.
Kaise Hota Hai?
Stimulus (jaise garam cheez chhuna).
Sensory neuron signal spinal cord tak le jata hai.
Interneuron signal process karta hai.
Motor neuron muscles ko signal bhejta hai action ke liye.
Example: Haath garam pan pe laga aur turant hata liya – yeh reflex action hai.
Reflex Arc: Yeh pathway hai jo reflex action ke liye use hota hai (Stimulus → Sensory Neuron → Interneuron → Motor Neuron → Response).
5. Coordination Between Nervous System and Other Systems
Nervous system body ke doosre systems (jaise endocrine system) ke saath milke kaam karta hai taaki body smoothly function kare.
Nervous System: Quick responses deta hai (jaise reflex actions).
Endocrine System: Slow, long-term responses deta hai (jaise growth, puberty).
Example: Jab tum darr jate ho, nervous system heart rate badhata hai (quick response), aur endocrine system adrenaline hormone release karta hai (longer effect).
6. Brain aur Nervous System Ke Interesting Facts
Brain mein ~86 billion neurons hote hain, aur har neuron thousands of connections bana sakta hai.
Brain body ka 2% weight hai, par 20% energy use karta hai.
Reflex actions itne fast hote hain ki brain tak signal jata hi nahi!
Brain mein pain receptors nahi hote, isliye brain surgery ke waqt dard nahi hota.
Example: Jab tum sapne dekhte ho, brain active hota hai aur memories process karta hai, isliye padhai ke baad sona zaroori hai.
7. Nervous System Ko Healthy Kaise Rakhein?
Balanced Diet: Omega-3 (fish, walnuts), vitamins (fruits, veggies) nervous system ke liye achhe hain.
Example: Badam khane se memory sharp hoti hai.
Exercise: Roz 20-30 minute walk ya yoga blood flow badhata hai, jo neurons ko oxygen deta hai.
Sleep: 7-8 hours ki neend brain aur neurons ko recharge karti hai.
Mental Stimulation: Puzzles, chess, ya reading se brain active rehta hai.
Stress Management: Meditation ya deep breathing se nervous system relax hota hai.
Example: Roz 10-minute meditation se stress kam hota hai aur brain focus karta hai.
8. Common Terms Explained
Synapse: Gap jahan neurons signals pass karte hain via neurotransmitters.
Neurotransmitters: Chemicals (jaise dopamine, serotonin) jo signals transfer karte hain.
Reflex Arc: Pathway jo reflex action ke liye use hota hai.
Cerebrospinal Fluid: Brain aur spinal cord ke liye cushion ka kaam karta hai.
Example: Dopamine neurotransmitter jab release hota hai (jaise favorite food khane se), toh khushi feel hoti hai.
Conclusion
Human brain aur nervous system body ke most important systems hain. Brain soch-vichar, memory, aur body functions ko control karta hai, jabki nervous system signals ke through body ko coordinate karta hai. Neurons, reflex actions, aur CNS-PNS ke saath yeh system humein environment ke saath interact karne mein help karta hai. NCERT syllabus ke hisaab se yeh notes complete hain aur har concept ko simple Hinglish mein cover karte hain.
Final Example: Jab tum yeh notes padh rahe ho, tumhara brain aur nervous system saath mein kaam kar rahe hain – sensory neurons text ko brain tak le jate hain, aur interneurons usse process karte hain taaki tum samajh sako!