Chemical Coordination and Integration | Hinglish| NEET Notes | Class 11 Biology

1. Hormonal Coordination in Human Body – Role of Endocrine and Neural Systems

Human body me hormonal coordination internal balance maintain karne me bohot important role play karti hai.
Neural system body ke different parts ke beech quick aur direct connection provide karta hai. Ye nerve signals ke through messages rapidly bhejta hai, jisse fast reactions possible hote hain. Lekin, ye coordination usually short-lived hoti hai aur nerves har single cell tak nahi pahuchte.

Har body cell ko continuously regulate karna zaroori hai, specially growth, metabolism, aur long-term changes ke liye.

Isliye, endocrine glands aur hormones ke roles ko samajhna crucial hai, kyunki ye hume batate hain ki body balance kaise maintain karti hai.

Endocrine glands aur hormones ka interaction various physiological processes ko regulate karne me vital hai.

Hormones chemical messengers hote hain jo blood ke through travel karte hain aur body ke har part tak pahuchte hain. Ye ensure karte hain ki functions smoothly aur continuously control me rahein.

Ye long-term coordination aur regulation possible hai endocrine system ke through, jo nervous system ke saath kaam karta hai. Dono milke major physiological activities jaise digestion, reproduction, metabolism, aur aur bhi processes ko manage aur coordinate karte hain.

Short me:

• Proper body functioning ke liye fast neural control aur slow but steady hormonal control dono chahiye.
• Ye dual system ensure karta hai ki body quickly react kare jab zaroorat ho aur balance maintain rahe over time.

Endocrine glands aur hormones ko directly bloodstream me release karke, ye ensure karte hain ki important signals body ke har part tak pahunch jaaye.

2. Endocrine Glands and Hormones – Functions, Structure, and Coordination

Endocrine glands aur hormones human body ke sabse important control systems me se ek banate hain.

Ye glands ductless hote hain, matlab inke paas tubes ya pipes nahi hote apne secretions carry karne ke liye. Isliye inhe ductless glands kehte hain. Ye hormones ko directly bloodstream me release karte hain.

Various endocrine glands aur hormones milke body functions jaise metabolism aur growth ko coordinate karte hain.

Ye endocrine system nervous system ke saath closely interact karta hai, taaki homeostasis maintain ho.

Pehle scientists ne hormone define kiya tha as chemical substance jo endocrine glands me banta hai aur blood ke through body me kisi specific organ tak jata hai.
Lekin aaj ka modern definition ye hai ki hormones non-nutrient chemical messengers hote hain.

• Ye energy nahi dete aur body parts nahi banate, jaise nutrients karte hain, lekin signals ke roop me kaam karte hain, jo cells ko communicate karne me help karte hain.
• Ye bahut chhoti (trace) amounts me bante hain, lekin ye tiny quantity bhi body me important effects la sakti hai.

Har endocrine gland aur hormone ka distinct function hota hai jo body ke overall health me contribute karta hai.

Endocrine glands aur hormones ka study medical aur biological sciences samajhne me help karta hai.
Ye bhi important hai ki dekha jaaye ki lifestyle factors endocrine glands aur hormones ko kaise affect karte hain.

Modern definition me major endocrine glands ke alawa bhi kuch chemicals include hote hain jo hormone jaise kaam karte hain — jaise tissues aur organs se aane wale signaling molecules.

Endocrine glands aur hormones ka effect emotions aur behavior pe bhi hota hai, jo psychological studies me important hai.

• Invertebrates (backbone nahi wale animals) me endocrine system simple hota hai aur few hormones hote hain.
• Vertebrates, especially humans me, system complex hai aur bohot saare hormones hote hain jo growth, metabolism, reproduction, aur aur bhi activities coordinate karte hain.

Ye hume human endocrine system ke study ki taraf le jaata hai, jo important glands jaise pituitary, thyroid, adrenal, pancreas, aur others include karta hai.
Har gland ka specific role hota hai jo body ke internal balance maintain karne me help karta hai.

Endocrine glands aur hormones ka impact contemporary health issues pe samajhna modern medicine ke liye crucial hai.

3.1 Human Endocrine System – List of Glands and Hormone-Producing Organs

Human endocrine system ek powerful internal communication network hai, jo special glands aur hormone-producing tissues se bana hai, jo body me spread hote hain.

Ye glands ducts use nahi karte apni secretions transport karne ke liye; instead, ye hormones directly blood me release karte hain, jo various organs tak travel karke body functions regulate karte hain.

Endocrine glands human body ke sabse important control systems me se ek banate hain. Ye ductless hote hain aur apne chemicals (hormones) directly bloodstream me release karte hain. Various endocrine glands aur hormones milke metabolism, growth, aur aur bhi body functions coordinate karte hain.

In main glands ke alawa, kuch non-endocrine organs me bhi hormone-secreting cells ya tissues hote hain.

• Inme include hain gastrointestinal (GI) tract, liver, kidneys, aur heart.
• Inka primary role hormone production nahi hai, lekin ye important chemicals secrete karte hain jo hormone jaise kaam karte hain aur specific body functions regulate karne me help karte hain.

Aage ke sections me, hum har major gland ka structure aur function briefly padhenge, saath hi brain ka ek important part — hypothalamus, jo entire endocrine system ko control karne me key role play karta hai, ko bhi samjhenge.

3.1 Hypothalamus – Structure, Hormones, and Role in Pituitary Regulation

Hypothalamus brain ka ek chhota lekin powerful part hai jo bohot saare body functions ko control karta hai. Ye forebrain ke diencephalon ke base me located hai aur endocrine system ko regulate karne me central role play karta hai.

Hypothalamus me special nerve cells hote hain jinhe neurosecretory cells kehte hain. Ye cells small clusters (nuclei) me grouped hote hain. Ye cells hormones produce karte hain jo directly pituitary gland ke functioning ko affect karte hain.

Hypothalamus ke do main types ke hormones hote hain:
🔹 Releasing hormones – Ye pituitary gland ko stimulate karte hain ki wo apne hormones release kare.
🔹 Inhibiting hormones – Ye pituitary se hormone secretion ko suppress ya block karte hain.

Example:

• Gonadotrophin Releasing Hormone (GnRH) hypothalamus se release hota hai aur pituitary ko gonadotrophins release karne ke liye stimulate karta hai, jo reproductive functions control karte hain.
• Somatostatin ek inhibiting hormone hai jo growth hormone (GH) release ko pituitary se block karta hai.

Hypothalamic neurons me bane hormones axons ke through travel karte hain aur nerve endings par release hote hain. Wahan se ye hormones special portal circulatory system (blood vessels ka network) me jaate hain jo unhe anterior pituitary gland tak le jaata hai, jahan ye hormone production control karte hain.

Posterior pituitary ye hormones se control nahi hoti; ye directly nerve signals ke through hypothalamus se regulate hoti hai — is process ko neural regulation kehte hain.

Is tarah, hypothalamus master controller ki tarah kaam karta hai, nervous system aur endocrine system ko connect karta hai, aur ensure karta hai ki hormone levels balance me rahein taaki body proper function kare.

3.2 Pituitary Gland – Hormones, Functions, Disorders, and Regulation

Pituitary gland, jise master gland bhi kehte hain, endocrine system ko control karne me major role play karti hai.

• Ye small bony cavity (sella turcica) me skull ke andar located hai aur stalk-like structure ke through hypothalamus se connected hai.
• Pituitary gland ke do major parts hote hain:
  1. Adenohypophysis (anterior pituitary)
  2. Neurohypophysis (posterior pituitary)

1️⃣ Adenohypophysis (anterior pituitary) ke do regions hain:

🔹 Pars distalis (anterior pituitary) – Ye 6 major hormones secrete karta hai:

• Growth Hormone (GH) – Body growth control karta hai
• Prolactin (PRL) – Mammary glands me milk production stimulate karta hai
• Thyroid Stimulating Hormone (TSH) – Thyroid hormone production stimulate karta hai
• Adrenocorticotropic Hormone (ACTH) – Adrenal cortex ko glucocorticoids produce karne ke liye stimulate karta hai
• Luteinizing Hormone (LH) – Females me ovulation trigger karta hai, males me androgen release stimulate karta hai
• Follicle Stimulating Hormone (FSH) – Males me sperm formation me help karta hai, females me ovarian follicles develop karne me

🔹 Pars intermedia – Melanocyte Stimulating Hormone (MSH) secrete karta hai, jo skin pigmentation regulate karta hai melanocytes par act karke. Humans me ye part mostly anterior pituitary ke saath merge hota hai.

2️⃣ Neurohypophysis (posterior pituitary) – Ye apne hormones produce nahi karta, lekin hypothalamus ke hormones store aur release karta hai:

• Oxytocin – Childbirth me strong uterine contractions stimulate karta hai aur breastfeeding me milk ejection help karta hai
• Vasopressin (Antidiuretic Hormone, ADH) – Kidneys me water reabsorption badhakar water loss kam karta hai, dehydration prevent karta hai

GH ka excess childhood me gigantism cause karta hai, aur low secretion pituitary dwarfism. Adults me excess GH se acromegaly ho sakta hai, especially face aur bones ko affect karta hai.

LH aur FSH ko gonadotrophins kehte hain kyunki ye gonadal functions control karte hain:

• Males: LH → androgen secretion from testes; FSH + androgens → sperm production regulate
• Females: LH → ovulation & corpus luteum support; FSH → ovarian follicle development

MSH → skin color control karta hai pigment-containing cells par act karke.

ADH deficiency → Diabetes Insipidus, jisme kidneys water conserve nahi karte, leading to excessive urination aur dehydration.

3.3 Thyroid Gland – Structure, Hormones, Functions & Related Disorders

Thyroid gland human body ke sabse important endocrine glands me se ek hai.

• Ye do lobes me divided hai, jo trachea (windpipe) ke dono sides me located hain, aur isthmus naam ke thin connective tissue bridge se dono lobes judte hain.
• Thyroid gland ke andar bahut saare follicles hote hain, jisme follicular cells central cavity ke around arranged hote hain. Ye cells do major hormones produce karte hain:
  🔹 Tetraiodothyronine (T4 ya thyroxine)
  🔹 Triiodothyronine (T3)

Ye dono hormones iodine-dependent hote hain, matlab inko banane ke liye body me enough iodine hona chahiye. Agar iodine ki kami ho, to hypothyroidism hota hai — gland properly kaam nahi karta.

• Hypothyroidism ka ek visible effect thyroid ka swelling hai, jise goitre kehte hain.
• Pregnant women me hypothyroidism se baby me cretinism ho sakta hai — stunted physical aur mental development, low IQ, abnormal skin, deaf-mutism, aur delayed growth.
• Adult women me ye irregular menstrual cycles bhi cause kar sakta hai.

Dusri taraf, agar thyroid overactive ho jaye — jaise cancer ya nodules ki wajah se — to hormones excess me produce hote hain, jise hyperthyroidism kehte hain.

• Ye body balance disrupt karta hai aur metabolism ko abnormal tarike se increase karta hai.
• Example: Exophthalmic goitre (Graves’ disease) — symptoms: bulging eyes, rapid weight loss, enlarged thyroid, increased basal metabolic rate.

Thyroid hormones ke main functions:
✔ Basal Metabolic Rate (BMR) regulate karna — resting energy use speed
✔ Red blood cell formation support karna
✔ Carbohydrates, proteins, fats ka metabolism help karna
✔ Body me water aur electrolyte balance maintain karna

T3 aur T4 ke alawa, thyroid gland thyrocalcitonin (TCT) bhi produce karta hai, jo blood calcium level kam karta hai aur calcium regulation me help karta hai.

3.4 Thymus Gland: Powerful Role in Immunity

Thymus gland immune system me bahut important role play karta hai, especially childhood aur adolescence ke dauran.

• Ye gland thymosins release karta hai, jo immune defense ke development aur functioning ke liye crucial hote hain.
• Thymosins ka main kaam hai immature T-lymphocytes ko mature karna, jisse cell-mediated immunity strong hoti hai.
• Ye humoral immunity ko bhi enhance karte hain by antibody production support kar ke.

Lekin jaise-jaise age badhti hai, thymus gland dheere-dheere shrink hone lagta hai, jiski wajah se thymosin production kam ho jata hai aur immune response weak ho jata hai.

3.5 Pineal Gland: Natural Regulator of Sleep and Body Rhythms

Pineal gland ek chhoti, pea-shaped structure hai jo forebrain ke dorsal side me located hai.

• Chhoti hone ke bawajood, ye ek powerful function perform karta hai — melatonin hormone produce karta hai, jo body ka internal clock ka kaam karta hai.
• Melatonin mainly 24-hour (diurnal) biological rhythm maintain karta hai, jisme sleep-wake cycle aur body temperature regulation jaise daily patterns shamil hain.
• Matlab, pineal gland body ko signal deta hai ki kab sone ka time hai aur kab jagne ka, jo eyes se light receive hone ke amount par depend karta hai.

Melatonin ke aur bhi kaam hain:
✔ Metabolism regulate karna
✔ Skin pigmentation control karna
✔ Female menstrual cycle ko affect karna
✔ Body’s defense system (immunity) support karna

• Isliye, pineal gland sirf sleep regulator nahi, balki ek multi-functional hormone gland hai jo physical aur mental health ke kai aspects ko impact karta hai.
• Pineal gland ka function samajhne se aap healthy lifestyle aur better sleep patterns maintain kar sakte hain.

3.6 Parathyroid Gland: Key Hormone Regulating Calcium Levels in Body

Parathyroid glands chaar chhoti lekin bahut important endocrine glands hai jo thyroid gland ke back side par sthit hai, with one pair embedded in each lobe of the thyroid. Ye glands secrete karte hai ek vital peptide hormone known as parathyroid hormone (PTH), jo major role play karta hai calcium balance maintain karne me body me.

PTH ka release automatically regulated hota hai by the amount of calcium (Ca²⁺) circulating in the blood. Jab calcium levels drop karte hai, parathyroid gland respond karta hai by releasing more PTH to restore balance.

Ye hormone act karta hai multiple ways me — ye stimulate karta hai bone resorption, ek process jahan calcium release hota hai bones se bloodstream me, jo blood calcium levels increase karta hai. Ye enhance bhi karta hai calcium reabsorption by the renal tubules in kidneys aur boost karta hai calcium absorption from digested food in the intestines.

Isse PTH ek hypercalcemic hormone ban jata hai, matlab ye blood me calcium concentration raise karta hai. Saath me ek aur hormone called TCT (Thyrocalcitonin) ke, PTH play karta hai critical role in calcium homeostasis, ensuring ki body me exactly right amount of calcium ho for bone strength, nerve function, aur muscle activity.

Clearly, parathyroid gland ek chhoti gland hai lekin health par iska impact bahut bada hai.

3.7 Pancreas: Dual Role in Digestion and Blood Sugar Regulation Explained

Adrenal glands ek pair ke chhote, triangular-shaped endocrine glands hai jo har kidney ke upar sthit hai. Har adrenal gland do distinct regions se bana hota hai — adrenal medulla center me aur adrenal cortex surrounding it. Ye regions alag-alag kaam karte hai lekin saath me ye body ke overall balance maintain karne me vital role play karte hai.

Adrenal cortex responsible hai important steroid hormones produce karne ke liye, jinhe corticoids kehte hai, jo include karte hai glucocorticoids, mineralocorticoids, aur androgenic steroids.

• Glucocorticoids, mainly cortisol, help karte hai carbohydrate metabolism manage karne me by promoting gluconeogenesis, lipolysis, aur proteolysis — matlab ye glucose generate karte hai fats aur proteins se. Cortisol inflammation reduce karta hai, kidney aur cardiovascular function support karta hai, RBC production boost karta hai, aur zarurat padne par immune response suppress karta hai.
• Mineralocorticoids, especially aldosterone, regulate karte hai electrolytes aur body fluids ka balance. Aldosterone act karta hai renal tubules par sodium aur water reabsorb karne ke liye, aur potassium aur phosphate excrete karne ke liye, isse blood pressure, osmotic balance, aur fluid volume maintain hota hai.
• Androgenic steroids adrenal cortex se chhoti matra me release hote hai, jo puberty ke dauran axial hair, pubic hair, aur facial hair development promote karte hai.

Structurally, adrenal cortex me teen layers hoti hai — zona glomerulosa (outer), zona fasciculata (middle), aur zona reticularis (inner), aur har layer hormone production me contribute karti hai.

Agar adrenal cortex sufficient hormones produce nahi karta, to ye Addison’s disease lead kar sakta hai, jisme severe fatigue, weakness, aur disturbed metabolism hota hai.

Isliye, adrenal gland sirf stress ke liye nahi, balki ek multi-tasking hormonal hub hai jo energy, immunity, fluid balance, aur puberty-related changes ke liye essential hai.

3.8 Pancreas: Dual Role in Digestion and Blood Sugar Regulation Explained

Pancreas ek composite gland hai jo dono tarah kaam karta hai — exocrine aur endocrine gland ke roop me.

Endocrine part of pancreas me clusters of specialized cells hote hai jinhe Islets of Langerhans kehte hai, aur ye total mass ka sirf 1-2% hote hai.

• α-cells glucagon secrete karte hai, jo blood sugar levels badhata hai.
• β-cells insulin produce karte hai, jo glucose homeostasis ke liye crucial hai.

Saath me, ye dono cells blood me glucose ka delicate balance maintain karte hai.

3.9 Ovary: Powerful Female Gland Controlling Reproduction and Hormones

Ovary primary female sex organ hai, aur har female ke paas ek pair of ovaries hoti hain jo abdominal region me located hoti hain. Ye chhoti lekin powerful glands do major functions perform karti hain — ye ova (eggs) produce karti hain aur female sex hormones secrete karti hain. Har menstrual cycle ke dauran, ovary ek ovum release karti hai, jo reproduction ke liye essential hai. Structurally, ovary ovarian follicles aur stromal tissues se bani hoti hai. Growing ovarian follicles mainly responsible hoti hain estrogen, ek steroid hormone, ke production ke liye, jo female ke reproductive system aur physical characteristics ke multiple aspects ko influence karta hai. Ovulation ke baad, jab follicle ruptures hota hai, to ye ek temporary gland-like structure me transform ho jata hai jise corpus luteum kehte hain, jo doosra key hormone — progesterone — secrete karna start karta hai. Estrogen hormone female secondary sex organs ke growth aur functions ko stimulate karne me involved hai, ovarian follicles ke development me help karta hai, aur secondary sexual characters jaise high-pitched voice aur breast development ke appearance me lead karta hai. Estrogen female sexual behavior ko regulate karne me bhi role play karta hai. Dusri taraf, progesterone pregnancy maintain karne ke liye crucial hai. Ye mammary glands par act karta hai, alveoli — milk-storing sacs — ke development ko stimulate karta hai, aur milk secretion ko bhi enhance karta hai. Saath me, estrogen aur progesterone female body me various reproductive aur hormonal activities ko regulate karte hain, jo ovary ko female health aur fertility me central organ banata hai.

Knowledge about endocrine glands and hormones health aur human biology padhne wale kisi bhi vyakti ke liye essential hai.

Research on endocrine glands and hormones continue evolve ho rahi hai, jo unke health par effects ke naye insights reveal karti hai.

3.10 Testis: Dual Role in Male Reproduction and Hormonal Regulation

The testis ek vital organ hai male reproductive system me, aur har male ke paas ek pair of testes hoti hain jo scrotal sac me located hoti hain, jo abdominal cavity ke bahar latakti hai. Testis dual role perform karta hai — dono primary sex organ aur endocrine gland ke tarah kaam karta hai. Structurally, har testis seminiferous tubules aur interstitial (stromal) tissues se bani hoti hai. Seminiferous tubules ke beech ke spaces me specialized cells hoti hain jise Leydig cells ya interstitial cells kehte hain, jo male sex hormones ka group produce karne ke liye responsible hoti hain, jise androgens kehte hain, jisme sabse important testosterone hai. Ye androgens male accessory sex organs jaise epididymis, vas deferens, seminal vesicles, prostate gland, aur urethra ke development, maturation, aur proper functioning ko control karte hain.

Iske alawa, testosterone muscular growth ko promote karta hai, facial aur axillary hair ke development me help karta hai, deep ya low-pitched voice lata hai, aur male aggressiveness ko influence karta hai. Ye spermatogenesis me bhi crucial role play karta hai, jo process hai jisme sperm cells seminiferous tubules ke andar form hote hain. Testis hormones central nervous system par bhi act karte hain, male sexual behavior (libido) ko influence karte hain. Furthermore, androgens ka anabolic effect hota hai, matlab ye proteins ka synthesis stimulate karte hain aur carbohydrate metabolism ko regulate karte hain, jo muscle building aur energy use me contribute karta hai.

Is tarah, testis sirf reproduction ke liye hi nahi, balki male characteristics, fertility, aur overall hormonal balance ko define aur maintain karne ke liye bhi essential hai.

4 Hormones of Heart, Kidney, and Gastrointestinal Tract: Secret Roles in Body Functions

Besides the well-known endocrine glands, kuch non-endocrine organs aur tissues human body me bhi crucial hormones secrete karte hain jo various physiological processes ko support karte hain. Inme se heart, kidney, aur gastrointestinal (GI) tract kuch highly specialized hormones produce karte hain.

Heart, specifically atrial wall, ek peptide hormone Atrial Natriuretic Factor (ANF) secrete karta hai. Ye hormone blood pressure reduce karne me key role play karta hai. Jab blood pressure rise hota hai, ANF release hota hai, jis se blood vessels dilate hoti hain, aur blood pressure girta hai, jo cardiovascular balance maintain karne me help karta hai.

Kidneys me specialized juxtaglomerular cells erythropoietin, ek aur peptide hormone, produce karte hain, jo erythropoiesis — yani red blood cells (RBCs) ka formation bone marrow me — stimulate karta hai, jo body me oxygen transport ke liye essential hai.

Gastrointestinal tract me bhi endocrine cells hoti hain jo important digestive hormones secrete karti hain jaise gastrin, secretin, cholecystokinin (CCK), aur gastric inhibitory peptide (GIP). Gastrin gastric glands ko hydrochloric acid aur pepsinogen secrete karne ke liye stimulate karta hai, jo digestion me help karta hai. Secretin exocrine pancreas par act karta hai aur water aur bicarbonate ions ka release promote karta hai, jo stomach acid ko neutralize karta hai. CCK pancreas aur gallbladder ko target karta hai, pancreatic enzymes aur bile juice ka release food digestion ke liye help karta hai. GIP gastric secretions ko inhibit karta hai aur stomach motility reduce karta hai, digestion ko balance karta hai.

Additionally, kai aur non-endocrine tissues growth factors produce karte hain, jo normal tissue growth, repair, aur regeneration ke liye vital hain. Ye hormones aur factors, bhale hi typical endocrine glands ke bahar se secrete hote hain, body regulation aur internal harmony ke liye essential hain.

5. How Hormones Work: Their Mode of Action on Target Cells

Hormones apna effect specific organs ya tissues par dikhate hain, jise target tissues kehte hain. Har target tissue me specialized proteins hote hain jise hormone receptors kehte hain, jo sirf ek specific hormone se bind karte hain — bilkul waise jaise ek key particular lock me fit hoti hai.

Ye hormone receptors do main types ke hote hain, unke location ke hisaab se:

• Membrane-bound receptors – Target cells ke surface (cell membrane) par present hote hain.
• Intracellular receptors – Target cell ke andar, usually nucleus ke andar, present hote hain (jise nuclear receptors bhi kehte hain).

Jab koi hormone apne specific receptor se bind karta hai, to ye ek hormone-receptor complex form karta hai, jo cell ke andar biochemical changes trigger karta hai. Ye changes body ke various functions jaise metabolism, growth, reproduction, etc. ko regulate karte hain.

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🧪 Types of Hormones Based on Chemical Nature:

Hormones chemically char groups me classify kiye jaate hain:

• Peptide, polypeptide, aur protein hormones – Example: Insulin, Glucagon, Pituitary hormones, Hypothalamic hormones.
• Steroid hormones – Example: Cortisol, Testosterone, Estradiol, Progesterone.
• Iodothyronines (Thyroid hormones) – Example: Thyroxine (T4), Triiodothyronine (T3).
• Amino acid derivatives – Example: Epinephrine (Adrenaline).

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⚙️ How Hormones Act:

1. Hormones with Membrane-Bound Receptors:
   Ye hormones target cell me enter nahi karte.
   Iske bajaye, ye cell membrane par receptors se bind karte hain aur cell ke andar second messengers produce karte hain, jaise:

• cAMP (cyclic AMP)
• IP₃ (Inositol triphosphate)
• Ca²⁺ (Calcium ions)

Ye second messengers internal enzymes ya proteins ko activate karte hain jo required effect laate hain.
✅ Example: Insulin is method ke through kaam karta hai.

2. Hormones with Intracellular Receptors:
   Ye hormones lipid-soluble hote hain aur cell membrane me enter kar sakte hain.
   Cell ke andar, ye nuclear receptors se bind karte hain aur directly gene expression ya DNA function ko affect karte hain.
   Isse long-term effects ho sakte hain jaise cell growth, protein synthesis, aur development.
   ✅ Example: Steroid hormones aur thyroid hormones is mechanism ka use karte hain.

🔁 Final Outcome:
Chahe mechanism jo bhi ho, hormone action ka final result ye hota hai:

• Control metabolism
• Regulate physiological processes
• Maintain homeostasis
• Influence development and reproduction

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6. SUMMARY: Hormonal Regulation in Human Body

Human body hormones ka use chemical coordination, integration, aur regulation ke liye karta hai. Ye hormones specialized glands ya cells se secrete hote hain aur various functions ko affect karte hain jaise metabolism, growth, development, aur reproduction.

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🧠 Main Endocrine Glands and Their Hormones

🧠 Main Endocrine Glands and Their Hormones

1. Hypothalamus

• Pituitary gland ko control karta hai.
• Releasing aur inhibiting hormones produce karta hai.

2. Pituitary Gland (Master gland)

• 3 parts hote hain:
  • Pars distalis (Anterior) – 6 major hormones secrete karta hai.
  • Pars intermedia – MSH (Melanocyte Stimulating Hormone) secrete karta hai.
  • Pars nervosa (Posterior) – oxytocin aur vasopressin secrete karta hai.
• Other endocrine glands aur body growth ko control karta hai.

3. Pineal Gland

• Melatonin secrete karta hai, jo sleep-wake cycle aur body temperature control karta hai.

4. Thyroid Gland

• Produce karta hai:
  • Thyroxine (T4) aur Triiodothyronine (T3) – BMR, brain development, aur metabolism ko regulate karte hain.
  • Calcitonin – blood calcium levels ko lower karta hai.

5. Parathyroid Glands

• Parathyroid hormone (PTH) secrete karti hain – blood calcium level badhata hai; calcitonin ke saath calcium balance karta hai.

6. Thymus Gland

• Thymosins secrete karta hai – T-cell maturation aur antibody production me help karta hai, immunity ke liye.
• Age ke saath shrink ho jata hai.

7. Adrenal Glands

• Adrenal Medulla:
  • Epinephrine aur norepinephrine secrete karta hai – alertness, heart rate, sweating, etc. badhate hain.
• Adrenal Cortex:
  • Glucocorticoids (e.g. cortisol) – glucose regulate karte hain, inflammation reduce karte hain, RBCs badhate hain.
  • Mineralocorticoids (e.g. aldosterone) – Na⁺/K⁺ balance aur BP control karte hain.
  • Chhoti amount me androgens bhi secrete hote hain.

8. Pancreas (Islets of Langerhans)

• α-cells: Glucagon secrete karte hain – blood sugar increase karta hai.
• β-cells: Insulin secrete karte hain – blood sugar lower karta hai.
• Imbalance hone par diabetes mellitus ho sakta hai.

9. Testis (males me)

• Androgens (mainly testosterone) secrete karta hai:
  • Male sex organs aur characters develop karte hain
  • Sperm production, protein synthesis, RBC formation, aur sex drive promote karte hain.

10. Ovary (females me)

• Secrete karti hai:
  • Estrogen – female sex organs, secondary sex characters develop karta hai.
  • Progesterone – Pregnancy maintain karta hai, aur mammary glands ko milk production ke liye support karta hai.

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🫀 Other Hormone-Secreting Organs (Non-Endocrine Tissues)

1. Heart

• Atrial Natriuretic Factor (ANF) secrete karta hai – blood pressure lower karta hai.

2. Kidneys

• Erythropoietin secrete karte hain – RBC formation stimulate karta hai.

3. Gastrointestinal (GI) Tract

• Secrete karta hai:
  • Gastrin – HCl aur pepsinogen increase karta hai.
  • Secretin – Bicarbonate increase karta hai.
  • CCK – Bile aur pancreatic enzymes release karta hai.
  • GIP – Gastric functions slow down karta hai.

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⚙️ Mechanism of Hormone Action

Hormones specific receptors se bind karte hain:

• Membrane-bound receptors: Second messengers ka use karte hain (jaise cAMP, Ca²⁺).
• Intracellular receptors: Cells ke andar enter karte hain aur directly gene expression ko affect karte hain (e.g., steroids, thyroid hormones).

Har hormone sirf apne matching receptor ke saath kaam karta hai.

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✅ Key Roles of Hormones:

ndocrine glands aur hormones ke roles ko samajhna bahut important hai, taaki ye samajh sake ki humari body balance kaise maintain karti hai.

• Growth, metabolism, immune system, blood pressure, digestion, reproduction, aur homeostasis ko regulate karte hain.
• Endocrine glands aur hormones ka study humare biological processes ko samajhne ka ek window provide karta hai.