Neural Control And Coordination | Class 11 Biology Notes For NEET In Hinglish
Introduction With 💖Learn Sufficient Notes💖
To maintain a healthy aur balanced internal environment humari body me, jo homeostasis ke naam se bhi jaana jaata hai, ye zaruri hai ki saare organs aur organ systems well-coordinated manner me kaam karein. Coordination ka matlab hai ki do ya zyada organs interact karein aur ek doosre ke functions ko support karein taaki body ki demands poori ho sakein.
For example, jab hum physical exercise karte hain, to humare muscles ko zyada energy ki zarurat hoti hai. Is increased demand ko meet karne ke liye, body oxygen supply badhati hai, matlab humare lungs tez saans lete hain, heart tez beat karta hai, aur blood vessels zyada oxygenated blood carry karte hain. Saath hi, rate of respiration bhi increase hoti hai taaki zyada energy ATP ke form me produce ho.
Iska result ye hota hai ki kai organs jaise muscles, lungs, heart, blood vessels, kidneys, aur nerves actively saath kaam karte hain. Lekin jab exercise ruk jaati hai, to ye saare organs dheere-dheere apne normal resting functions me wapas aate hain.
Ye poora process dikhata hai ki kaise different organs harmony me kaam karte hain aur body ke changing needs ke hisaab se respond karte hain. Ye possible hota hai do major systems ke through – neural system aur endocrine system. Ye do systems body me coordination aur communication maintain karne me bahut important role play karte hain.
Neural system ek high-speed network ki tarah kaam karta hai jo body ke different parts ko nerve signals ke through connect karta hai. Ye system quick aur specific responses allow karta hai through point-to-point electrical communication.
Dusri taraf, endocrine system hormones ka use karta hai, jo chemical messengers hain, slowly but steadily longer-lasting changes aur coordination laate hain different organs me.
Is chapter me, aap detail me human neural system ke baare me sikhenge, kaise ye kaam karta hai, kaise nerve impulses transmit hote hain, aur kaise messages ek neuron se doosre neuron tak synapses ke through pass hote hain. Ye mechanisms samajhna essential hai taaki ye grasp kiya ja sake ki humari body kaise balance maintain karti hai aur quickly react karti hai internal aur external stimuli par.
2. Human Neural System – Structure, Function and Coordination for Class 11 & NEET
Neural system sabhi animals ka ek vital part hai, aur ye special cells se bana hota hai jise neurons kehte hain. Ye neurons responsible hote hain signals ya stimuli ko detect, receive, aur ek body part se doosre body part tak send karne ke liye. Neurons body ko internal aur external changes ke liye rapidly messages pass karke respond karne me help karte hain.
Lower invertebrates jaise Hydra me, neural system bahut basic aur simple hota hai. Ye loose network of neurons se bana hota hai, jo body me spread hote hain. Ye neurons saath kaam karke basic functions control karte hain jaise movement aur response to touch.
Lekin, more evolved invertebrates jaise insects me, neural system zyada advanced ho jata hai. Insects ke paas brain, multiple ganglia (jo small clusters of neurons hote hain), aur well-organised neural tissues hote hain, jo body parts ke better control aur coordination me help karte hain.
Jab hum vertebrates jaise fishes, birds, aur humans ko dekhte hain, to neural system highly developed aur complex hota hai. Vertebrates ke paas well-defined central nervous system (CNS) hota hai, jo brain aur spinal cord include karta hai, aur ek peripheral nervous system (PNS) hota hai jo body ke saare parts ko CNS se connect karta hai.
Ye advanced system vertebrates ko allow karta hai sochne, seekhne, yaad rakhne, environment sense karne, aur accurate aur fast respond karne me.
Is tarah, jaise hi hum lower se higher animals ki taraf badhte hain, neural system ka structure aur function zyada complex aur efficient ho jata hai, jo body me better coordination, control, aur communication allow karta hai.
3. Detailed Explanation of Human Nervous System – Parts, Functions & more.
1. Division of Human Neural System
Human neural system broadly do main parts me divided hai – Central Neural System (CNS) aur Peripheral Neural System (PNS). Ye division body ko internal aur external communication dono effectively manage karne me help karta hai. CNS body ka main control center ke tarah kaam karta hai, jabki PNS messenger system ke tarah act karta hai, signals ko body aur CNS ke beech carry karte hue.
2. Central Neural System (CNS)
Central Neural System (CNS) me brain aur spinal cord included hote hain. Ye primary site hai jahan saari information process hoti hai aur decisions liye jaate hain. CNS incoming signals receive karta hai, unhe process karta hai, aur appropriate responses send karta hai. Chahe ye thinking, learning, reacting to touch, ya voluntary aur involuntary movements ko control karna ho, sab yahin handle hota hai. Basically, CNS poore body ka command center hai.
3. Peripheral Neural System (PNS)
Peripheral Neural System (PNS) me saare nerves included hote hain jo brain aur spinal cord se connected hote hain. Ye nerves wires ki tarah kaam karte hain jo information ko body ke different parts tak aur wapas carry karte hain. PNS poore body me extend karta hai, ensuring ki even most remote organs aur tissues CNS se communicate kar saken. PNS ka main role hai body ko brain aur spinal cord se link karna aur constant coordination maintain karna.
4. Afferent and Efferent Fibres of PNS
Nerve fibres in the PNS do main types ke hote hain – afferent fibres aur efferent fibres. Afferent fibres responsible hote hain sensory information ko various organs aur tissues se CNS ki taraf carry karne ke liye. For example, jab aap kuch hot touch karte ho, to afferent nerves ye information brain tak bhejte hain. On the other hand, efferent fibres CNS se different organs aur muscles tak instructions carry karte hain, taaki koi particular action perform ho sake, jaise moving your hand away from the hot object. Ye two-way communication system humari body ko responsive aur well-coordinated banaye rakhta hai.
5. Somatic Neural System
The Somatic Neural System PNS ka ek division hai jo voluntary control me body movements me help karta hai. Ye motor impulses CNS se skeletal muscles tak bhejta hai, jo conscious control me hote hain. Ye system hume allow karta hai walk, talk, write, lift objects, aur sab tarah ke voluntary actions perform karne me. Ye quickly act karta hai aur immediate physical responses me involved hota hai.
6. Autonomic Neural System
The Autonomic Neural System bhi PNS ka part hai, lekin ye involuntary functions ko control karta hai jaise heartbeat, digestion, aur breathing. Ye impulses CNS se smooth muscles, glands, aur internal organs tak bhejta hai. Somatic system ke unlike, humare paas in functions par direct control nahi hota. Autonomic system automatically kaam karta hai aur ensure karta hai ki body ka internal environment balanced rahe bina kisi conscious effort ke.
7. Sympathetic and Parasympathetic Divisions
The Autonomic Neural System further do parts me divided hai – Sympathetic Neural System aur Parasympathetic Neural System. Sympathetic system body ko emergency ya stressful situations ke liye prepare karta hai – ise “fight or flight” response bhi kehte hain. Ye heart rate increase karta hai, pupils ko dilate karta hai, aur blood ko muscles ki taraf redirect karta hai. On the other hand, parasympathetic system body ko relax karne aur stress ke baad normal state me return karne me help karta hai – ise “rest and digest” response bhi kehte hain. Ye heartbeat slow karta hai, digestion promote karta hai, aur energy conserve karta hai.
8. Visceral Nervous System
The Visceral Nervous System peripheral nervous system ka ek aur component hai. Isme saare nerves, fibres, ganglia (nerve cell clusters), aur plexuses (nerve networks) included hote hain, jo signals internal organs (viscera) se CNS tak aur wapas carry karte hain. Ye vital organs jaise heart, lungs, stomach, aur intestines ke function ko monitor aur regulate karne me key role play karta hai. Ye system ensure karta hai ki internal organs smoothly function karein aur body ke baaki parts ke saath coordination me rahein.
4. Neuron – Structure, Types and Function as the Basic Unit of Nervous System
1. Structure of a Neuron
A neuron human neural system ka basic structural aur functional unit hai. Ye ek tiny microscopic cell hai jo body me nerve impulses transmit karne me major role play karta hai. A neuron ke three main parts hote hain: cell body, dendrites, aur axon. Cell body, jo cyton ke naam se bhi jaana jaata hai, me cytoplasm, normal cell organelles, aur unique granules hote hain jise Nissl’s granules kehte hain, jo protein synthesis me help karte hain. Ye neuron ka main metabolic center hai jahan cell ki activities control hoti hain aur nutrients process hote hain.
2. Dendrites – Receiving Ends of a Neuron
Coming out from the cell body chhoti, tree-like branches hoti hain jise dendrites kehte hain. Ye short fibres hote hain jo repeatedly branch karte hain aur Nissl’s granules bhi contain karte hain. Dendrites ka main function hai signals ya impulses receive karna from other neurons ya sensory organs aur unhe cell body ki taraf carry karna. Ye antennae ki tarah act karte hain, incoming messages ko pick karte hain aur nervous system me information relay me help karte hain.
3. Axon – The Signal Sender
The axon ek long, single fibre hai jo cell body se extend hota hai. Iske end par ye branch out karta hai aur har branch ek bulb-like structure me end hoti hai jise synaptic knob kehte hain. Ye knobs synaptic vesicles contain karte hain, jo special chemicals jise neurotransmitters kehte hain, hold karte hain. Axon ka function hai nerve impulses ko cell body se door transmit karna, ya to kisi doosre neuron tak across a synapse, ya kisi muscle tak (neuromuscular junction). Yehi tarika hai jisse signals ek cell se doosre cell ya brain se body parts tak travel karte hain.
4. Types of Neurons Based on Structure
Neurons ko three types me classify kiya jaata hai depending on number of axons aur dendrites:
- Multipolar neurons: Ek axon aur do ya zyada dendrites hote hain. Ye commonly cerebral cortex of the brain me paye jaate hain aur higher processing functions jaise thinking aur learning me involved hote hain.
- Bipolar neurons: Ek axon aur ek dendrite hota hai. Ye retina of the eye me paye jaate hain aur vision-related activities me involved hote hain.
- Unipolar neurons: Sirf ek single axon cell body se nikalta hai. Ye usually embryonic stages of development me present hote hain.
5. Myelinated and Non-Myelinated Axons
Neurons ko unke axon covering ke type ke basis par bhi divide kiya ja sakta hai. Kuch axons myelinated hote hain, matlab ye Schwann cells se covered hote hain jo axon ke around myelin sheath banate hain. Ye sheath nerve impulses ke transmission ko speed up karne me help karta hai. Sheath ke sections ke beech chhote gaps hote hain jise Nodes of Ranvier kehte hain, jo signal ko rapidly node se node jump karne allow karte hain. Myelinated fibres mainly spinal nerves aur cranial nerves me paye jaate hain.
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6. Non-Myelinated Axons
Non-myelinated fibres me Schwann cells present hote hain, lekin ye axon ke around myelin sheath nahi banate. Ye types of nerve fibres impulses ko myelinated fibres ke comparison me slowly conduct karte hain. Non-myelinated fibres commonly autonomic nervous system (jo involuntary activities ko control karta hai) aur somatic nervous system (jo voluntary movements ko control karta hai) me paye jaate hain. Dono types ke fibres body me different functions ke liye important hain.
5. Nerve Impulse – Generation, Conduction & Mechanism
1. Neurons and Their Polarised Membrane
Neurons special hote hain kyunki ye excitable cells hote hain, matlab ye electrical signals generate aur conduct kar sakte hain. At rest (jab koi signal send nahi ho raha), neuron ki membrane ko polarised state me kaha jaata hai. Iska matlab hai ki neuron ki membrane ka inner side negatively charged aur outer side positively charged hota hai.
Ye polarity tab hoti hai jab neuron ki membrane me different types ke ion channels present hote hain, jo selectively permeable hote hain—certain ions ko easily pass karne allow karte hain aur dusre ko nahi. At rest, membrane potassium ions (K⁺) ke liye zyada permeable hoti hai lekin sodium ions (Na⁺) ke liye almost impermeable hoti hai. Saath hi, neuron ke andar negatively charged proteins membrane cross nahi kar sakte.
Iska result ye hota hai ki neuron ke andar (axoplasm) zyada K⁺ aur negative proteins hote hain, jabki bahar ke fluid me zyada Na⁺ aur kam K⁺ hota hai, jo ek concentration gradient create karta hai.
2. Role of Sodium-Potassium Pump in Resting Potential
Is ionic difference ko maintain karne ke liye, ek special protein jise sodium-potassium pump kehte hain, actively membrane ke across kaam karta hai. Ye pump 3 Na⁺ ions ko cell se bahar le jaata hai aur 2 K⁺ ions ko cell ke andar laata hai, ATP se energy use karke. Is exchange ki wajah se, outside zyada positively charged ho jaata hai compared to inside. Ye difference in electrical charge across the membrane ko resting potential kehte hain, jo neuron ko ready karta hai ki wo quickly respond kare jab koi stimulus aaye.
3. What Happens When a Stimulus Arrives – Depolarisation
Jab koi stimulus (jaise touch ya pain) neuron ki membrane ke kisi particular point (e.g., point A) par lagta hai, to wo area Na⁺ ions ke liye highly permeable ho jaata hai. Iska result ye hota hai ki Na⁺ ions rapidly neuron ke andar rush karte hain. Ye sudden inflow polarity ko point A par reverse kar deta hai – inner surface positively charged ho jaata hai aur outer surface negatively charged ho jaata hai. Is state ko depolarisation kehte hain, aur is point ke across jo voltage difference hota hai, use action potential kehte hain, jo actual nerve impulse hai.
4. How the Impulse Travels – Current Flow and Conduction
Just point A ke aage (maan lo point B), membrane abhi bhi at rest hai – iska outside positive aur inside negative hai. Isliye, ek electric current axon ke andar point A se B ki taraf flow karta hai, aur bahar se B se A ki taraf, completing the circuit of current flow. Ye current ki movement membrane ko point B par bhi depolarise karne ke liye cause karti hai, aur wahan ek new action potential generate hota hai. Ye chain reaction axon ki length ke along continue hota hai, jisse impulse step-by-step forward travel karta hai.
5. Repolarisation – Restoring the Resting State
Jab action potential kisi site par generate ho jaata hai, to membrane lambe time tak depolarised nahi rehti. Bahut jaldi Na⁺ channels close ho jaate hain, aur membrane K⁺ ions ke liye zyada permeable ho jaati hai, aur K⁺ neuron ke bahar move karna start karta hai. Ye K⁺ ions ka outflow original polarity ko restore karta hai – inside phir se negative aur outside positive ho jaata hai. Is process ko repolarisation kehte hain, aur neuron ab ready hai next stimulus ke liye. Depolarisation aur repolarisation ka pura process sirf ek fraction of a second me hota hai.
6. Transmission of Nerve Impulses – Synapses, Neurotransmitters & Signal Flow
Human nervous system me, ek nerve impulse ka transmission ek neuron se doosre neuron tak ek special connection ke through hota hai jise synapse kehte hain. Synapse wo point hai jahan ek neuron ka end (pre-synaptic neuron) doosre neuron (post-synaptic neuron) se connect karta hai. In dono neurons ke beech, kabhi ek chhota fluid-filled gap hota hai jise synaptic cleft kehte hain, lekin kuch cases me, dono membranes bahut close hote hain. Synapses key structures hain jo messages ko nervous system me travel karne allow karte hain aur neural coordination ke liye essential hote hain. Human body me mainly do types ke synapses hote hain – electrical synapses aur chemical synapses.
Electrical Synapses – Direct Current Flow Between Neurons
Electrical synapses wo type ke synapses hote hain jahan pre-synaptic aur post-synaptic neurons ki membranes itni close hoti hain ki ye direct electric current ka flow ek neuron se doosre neuron tak allow karte hain. Ye type ke synapses us tarah kaam karte hain jaise ek impulse ek single neuron ke along move karta hai. Kyunki yahan koi gap ya delay nahi hota, impulse transmission electrical synapses me extremely fast hota hai. Lekin, electrical synapses human nervous system me bahut rare hote hain. Inka main function ye hai ki neurons ke beech quick communication allow karna jab speed crucial ho, jaise kuch reflexes ya early development stages me.
Chemical Synapses – Neurotransmitter-Based Communication
On the other hand, chemical synapses human body me sabse common type ke synapses hain. Is type me, dono neurons ki membranes ek gap se separated hoti hain jise synaptic cleft kehte hain, jo fluid se filled hota hai. Kyunki yahan gap hai, electric signal directly jump nahi kar sakta. Iske instead, signal ko chemicals ke form me pass kiya jaata hai jise neurotransmitters kehte hain. Ye neurotransmitters neurons ke beech gap ko bridge karte hain aur message ko across carry karte hain.
How Neurotransmitters Work at Chemical Synapses
Jab ek nerve impulse (jise action potential bhi kehte hain) pre-synaptic neuron ke axon ke end tak pahunchta hai, to ye vesicles (tiny bubble-like structures) ko axon terminals me stimulate karta hai. Ye vesicles neurotransmitter molecules se filled hote hain. Jaise hi impulse arrive hota hai, ye vesicles axon terminal ki membrane ki taraf move karte hain aur uske saath fuse ho jaate hain, releasing neurotransmitters into the synaptic cleft. Ye neurotransmitters phir post-synaptic neuron ki membrane par specific receptors se bind karte hain.
Effect of Neurotransmitter Binding on the Next Neuron
Jab neurotransmitters post-synaptic membrane ke receptors se attach ho jaate hain, to ye ion channels ko open karte hain. Isse certain ions post-synaptic neuron me flow karte hain. In ions ka flow ek new electrical potential generate karta hai, jo post-synaptic neuron me ek new nerve impulse ka result ho sakta hai. Ye new signal ya to excitatory ho sakta hai (jo nerve signal continue karta hai) ya inhibitory (jo signal ko block karta hai). Ye pura process ensure karta hai ki neurons ke beech communication accurately aur efficiently ho.
7. Brain and Spinal Cord Structure & Functions | Central Nervous System (CNS)
Brain humare nervous system ka sabse important organ hai. Ye body ka main control center ke tarah kaam karta hai, aur har tarah ki information ko process karta hai. Ye voluntary actions me major role play karta hai jaise hands aur legs ko move karna, aur saath hi involuntary functions me bhi jaise heartbeat, breathing, kidney function, aur digestion.
Iske alawa, brain responsible hai body balance maintain karne ke liye, body temperature control karne ke liye (thermoregulation), hunger aur thirst manage karne ke liye, aur 24-hour internal clock (circadian rhythm) maintain karne ke liye. Ye endocrine glands (hormone-secreting glands) ke working ko bhi control karta hai, aur human behaviour ke various aspects jaise mood aur personality ko influence karta hai.
Sabse important, ye main center hai senses jaise vision aur hearing ko process karne ke liye, aur saath hi speech, memory, emotions, thoughts, intelligence, aur learning ko handle karta hai.
Protection of the Brain – Skull and Cranial Meninges
Kyuki brain itna delicate aur important hai, isse achhi tarah protect kiya gaya hai skull ke through, jo ek bony structure hai aur head ko form karta hai. Lekin protection yahi khatam nahi hoti. Skull ke andar, brain ko teen special protective coverings se wrap kiya gaya hai jise cranial meninges kehte hain. Ye meninges teen layers se bane hote hain:
Dura mater – Outermost layer, jo thick aur tough hai.
Arachnoid – Middle layer, jo bahut thin aur web-like hai.
Pia mater – Innermost layer, jo soft aur delicate hai, aur direct contact me rehti hai brain tissue ke saath.
Ye layers brain ko cushioning, support, aur protection provide karte hain injury, infection, aur pressure changes se.
Major Parts of the Brain – Forebrain, Midbrain, and Hindbrain
Human brain functionally aur structurally teen major parts me divided hai:
Forebrain – Ye sabse largest part hai aur thinking, reasoning, memory, aur voluntary movements ko control karta hai.
Midbrain – Ye part ek bridge ki tarah kaam karta hai jo brain ke different parts ko connect karta hai. Ye sensory information ka coordination help karta hai, especially vision aur hearing se related.
Hindbrain – Ye part automatic functions ko control karta hai jaise heartbeat, breathing, aur body balance.
Inme se har part ka apna role hai, lekin ye sab milke body ko smoothly function karne me help karte hain.
8. Forebrain – Structure, Functions of Cerebrum, Thalamus & Hypothalamus
Forebrain human brain ka sabse largest aur most developed part hai. Ye teen main parts se milke bana hai: cerebrum, thalamus, aur hypothalamus. Inme se, cerebrum sabse bada portion hai aur thinking, decision-making, memory, emotions, aur voluntary actions me key role play karta hai. Cerebrum ke center me ek deep groove hota hai, jo isse do hemispheres me divide karta hai – left cerebral hemisphere aur right cerebral hemisphere. Ye dono halves nerve fibers ke bundle se connected hote hain jise corpus callosum kehte hain, jo dono sides ke brain ke beech communication allow karta hai.
Cerebral Cortex and Its Role in Higher Brain Functions
Cerebrum ki outermost layer ko cerebral cortex kehte hain. Ye layer tightly packed neuron cell bodies se bani hoti hai, jo ise greyish color deti hai, isliye ise commonly “grey matter” bhi kehte hain. Cerebral cortex ki surface par bahut saari folds hoti hain, jo surface area badhane me help karti hain taaki zyada neuron connections ho sake. Cortex me motor areas (jo muscle movement ko control karte hain), sensory areas (jo sense organs se signals receive karte hain), aur association areas hote hain. Ye association areas directly sensing ya movement se linked nahi hote, lekin ye complex processes jaise memory, communication, logical thinking, aur different sensory inputs ka integration handle karte hain.
White Matter – Inner Layer of the Cerebrum
Grey matter ke neeche white matter hoti hai, jo nerve fibers se bani hoti hai jo myelin sheath se covered hote hain. Ye myelinated fibers alag-alag brain areas ke beech messages ko quickly transmit karte hain. Kyunki yahan myelin present hai (jiska whitish appearance hota hai), ye region white aur shiny dikhta hai. White matter ek communication highway ki tarah kaam karta hai, ensure karte hue ki brain ke sab parts coordination me kaam karein.
Thalamus – Relay Centre for Sensory and Motor Signals
Thalamus cerebrum ke bilkul neeche hota hai aur sensory aur motor information ke liye ek central hub ka kaam karta hai. Ye sense organs se signals ko cerebral cortex ke correct parts tak relay karne me help karta hai. Ye sensory input ko filter aur focus karne me bhi role play karta hai, ensure karte hue ki sirf important signals process ho. Is tarah, ye ek major coordinating center hai jo brain ko incoming aur outgoing signals efficiently handle karne me help karta hai.
Hypothalamus – Master Regulator of Body Functions
Thalamus ke bilkul neeche hypothalamus hota hai, jo chhota lekin bahut important part hai brain ka. Ye bahut saare automatic aur vital body functions ko control karta hai. Isme centers hote hain body temperature, hunger, thirst, aur sleep-wake cycles ko regulate karne ke liye. Hypothalamus me neurosecretory cells bhi hote hain, jo special hormones secrete karte hain jise hypothalamic hormones kehte hain. Ye hormones pituitary gland ke functioning ko influence karte hain, isliye hypothalamus nervous system aur endocrine system ke beech ek key link hai.
Limbic System – The Emotional and Motivational Brain
Cerebral hemispheres ke inner parts, saath hi kuch deeply embedded structures jaise amygdala aur hippocampus, milke limbic system (jise limbic lobe bhi kehte hain) banate hain. Ye system, hypothalamus ke saath milkar, emotions, sexual behavior, aur motivation ko control karne me essential role play karta hai. Ye decide karta hai ki hum emotionally kaise feel aur react karte hain, jaise pleasure, fear, anger, aur excitement. Limbic system long-term memory formation aur learning processes me bhi contribute karta hai, especially emotional experiences se related.
9. Midbrain – Structure, Corpora Quadrigemina & Role in Neural Coordination
Midbrain ek chhota lekin important part hai brain ka jo forebrain aur hindbrain ke beech hota hai. Ye specifically forebrain ke thalamus aur hypothalamus ke neeche aur hindbrain ke pons ke upar located hai. Ye central position midbrain ko allow karta hai ki wo different parts of the brain ke beech ek connecting bridge ka kaam kare. Ye information relay karne me major role play karta hai, especially visual aur auditory responses, motor control, aur alertness se related.
Midbrain ke center me ek narrow canal hota hai jise cerebral aqueduct kehte hain. Ye canal brain ke do cavities — third ventricle (forebrain me) aur fourth ventricle (hindbrain me) ko connect karta hai. Ye cerebrospinal fluid (CSF) ka flow allow karta hai, jo brain ko protect karta hai aur pressure balance maintain karta hai.
Midbrain ke dorsal part (upper side) me four small round swellings hote hain jise corpora quadrigemina kehte hain. Ye swellings do pairs me divided hain — superior colliculi aur inferior colliculi. Superior colliculi visual information process karne aur eye movements coordinate karne me help karte hain, jabki inferior colliculi auditory signals (sound) aur hearing-related reflexes handle karte hain. Ye structures milkar body ko visual aur sound stimuli par quickly respond karne me help karte hain — jaise sir turn karna jab koi loud noise sunai de ya jab kuch aankhon ke samne flash ho.
10. Hindbrain – Structure and Functions of Pons, Cerebellum & Medulla Oblongata
Hindbrain brain ka lower back portion hai jo directly spinal cord se connected hai. Ye teen main parts se bana hai – pons, cerebellum, aur medulla oblongata (jo simply medulla bhi kehlata hai). Inme se har part body ke automatic aur coordination-related functions ko manage karne me special role play karta hai.
Pons hindbrain ka ek part hai jo nerve fibers (fibre tracts) contain karta hai. Ye fibers different areas of the brain ko ek dusre se connect karte hain. Basically, pons ek bridge ka kaam karta hai, messages cerebrum, cerebellum, aur medulla ke beech carry karne me. Ye breathing control me bhi role play karta hai aur respiration ke rhythm ko regulate karne me help karta hai.
Cerebellum pons ke just peeche located hai aur ye main brain ke neeche ek chhota brain jaisa dikhta hai. Iska surface highly folded (convoluted) hai, jo surface area increase karta hai aur zyada neurons pack hone allow karta hai. Ye structure cerebellum ko extremely efficient banata hai body balance, posture, muscle coordination, aur fine motor skills handle karne me. Ye ensure karta hai ki body movements smooth aur well-coordinated ho. Jaise, jab aap walk, run, ya write karte ho, cerebellum aapke movements ko control me rakhta hai.
Medulla oblongata, ya simply medulla, brain ka lowest part hai, jo brain ke spinal cord se connection ke bilkul paas located hai. Ye vital involuntary functions ko control karne me critical role play karta hai, jinke baare me hum consciously nahi sochte. Inme breathing (respiration), heart rate aur blood pressure (cardiovascular reflexes) aur digestion (jaise gastric secretions) shamil hain. Is wajah se, medulla brain ke most important survival centers me se ek maana jata hai.
Saath me, midbrain, pons, aur medulla oblongata milkar brain stem banate hain. Brain stem brain aur spinal cord ke beech communication link ka kaam karta hai, messages back and forth carry karta hai. Ye basic life-sustaining functions ko bhi control karta hai, jo ise survival ke liye essential banata hai.
11. Neural System – Chapter Summary with Key Concepts & Highlights
Neural system humare body me sabhi body activities ko coordinate aur integrate karne ke liye responsible hai. Ye ensure karta hai ki sabhi organs properly work karein, aur metabolic processes aur homeostasis (internal balance) maintain ho. Neural system ka working unit hai neuron, jo ek type ka cell hai jo electrical impulses generate aur conduct kar sakta hai. Ye ability neuron ke membrane ke dono sides me ion concentrations ke difference ki wajah se aati hai. Jab neuron rest me hota hai, ye difference ek charge create karta hai jo resting potential kehlata hai.
Jab neuron activated hota hai, ek electrical signal jo nerve impulse kehlata hai, neuron ke length (axon) ke along travel karta hai. Ye signal wave ki form me move karta hai, jo depolarization (jahan inside positively charged hota hai) aur phir repolarization (resting state me wapas) se guzarta hai. Ek neuron se dusre neuron tak message synapse ke through pass hota hai, jo pre-synaptic neuron (sending end) aur post-synaptic neuron (receiving end) ke beech contact point hai. Kuch synapses me neurons ke beech chhota space hota hai jise synaptic cleft kehte hain. Chemical synapses me, special chemicals jo neurotransmitters kehlate hain, ye message gap ke across pass karne me help karte hain.
Human neural system do major parts se bana hai:
- Central Neural System (CNS)
- Peripheral Neural System (PNS)
CNS me brain aur spinal cord shamil hai. Brain khud teen main regions me divided hai:
- Forebrain
- Midbrain
- Hindbrain
Forebrain me cerebrum, thalamus, aur hypothalamus shamil hain. Cerebrum sabse bada part hai aur left aur right halves me split hai, jo corpus callosum naam ke structure se judte hain. Forebrain ka key part hai hypothalamus, jo body temperature, hunger, aur thirst control karta hai. Cerebral hemispheres ke andar, kuch deep structures hote hain jo hypothalamus ke sath milke limbic system banate hain. Ye system sense of smell (olfaction), automatic body responses, sexual behavior, emotions jaise fear ya pleasure, aur motivation me involved hai.
Midbrain eyes (visual), skin (touch), aur ears (sound) se aane wali sensory information process aur combine karne me help karta hai. Ye visual, tactile, aur auditory signals ka integrating center ka kaam karta hai.
Hindbrain me pons, cerebellum, aur medulla oblongata shamil hain. Cerebellum body balance aur coordination maintain karne me key role play karta hai. Ye ears ke semicircular canals aur auditory system se information receive karke body posture manage karta hai. Medulla me vital processes jaise breathing, heart rate, aur digestive secretions regulate karne ke centers hote hain. Pons me nerve fibers hote hain jo different parts of the brain ko connect karte hain, taki wo smoothly ek sath work karein.
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