Class 9 Science – Chapter 6: TISSUES (Explained in Hinglish)

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Class 9 Science – Chapter 6: TISSUES (Explained in Hinglish)

🌿 Pehle ke chapter mein humne padha tha ki saare living organisms cells se bane hote hain. Lekin jab organism multicellular (bahu-koshikiy) hota hai, toh unki body mein alag-alag kaam karne ke liye alag-alag cells hote hain. Inhi kaamo ko efficiently karne ke liye, similar cells group banakar tissues bana lete hain.

⚫️ TISSUE Kya Hota Hai?

Tissue ek group hota hai aise cells ka jo structure mein similar hote hain aur milkar ek hi type ka kaam karte hain.

Examples:

  • Human body mein blood, muscles, nerve tissue
  • Plants mein xylem, phloem, parenchyma

Tissues banne ka fayda kya hai?
Multicellular organisms mein tissues ka hona bahut zaroori hai, kyunki alag-alag kaam ko divide karke har tissue efficiently karta hai.

🌿 PLANT TISSUES

✅ Main Types:

  1. Meristematic Tissue (Vikas-sheel)
  2. Permanent Tissue (Sthayi)

✔️ Meristematic Tissue

Yeh tissue wo hote hain jo constantly divide karte rehte hain aur naye cells banate hain. Isliye plant ka growth sirf kuch specific areas mein hota hai jahan yeh tissues hote hain.

♻ Types of Meristematic Tissue:

  1. Apical Meristem
    • Location: Root aur shoot ke tips
    • Function: Length badhata hai (growth in height)
  2. Lateral Meristem
    • Location: Stem ya root ke sides
    • Function: Girth ya motai badhata hai (growth in width)
  3. Intercalary Meristem
    • Location: Leaf base ya nodes par
    • Function: Internodes ko lamba karta hai

Meristematic Cells ke features:

  • Zyada active hote hain
  • Dense cytoplasm
  • Thin walls
  • Nucleus bada hota hai
  • Vacuole nahi hota (kyunki continuously divide kar rahe hain)

✔️ Permanent Tissue

Jab meristematic cells divide karna band kar dete hain aur ek special function lene lagte hain to wo Permanent Tissue ban jaate hain.

Is process ko kehte hain differentiation.

Types:

  1. Simple Permanent Tissue (Ek hi type ke cells)
  2. Complex Permanent Tissue (Alag-alag type ke cells)

Simple Permanent Tissue:

  1. Parenchyma
    • Sabse common tissue
    • Living cells, thin walls, intercellular space hoti hai
    • Function: Food store karta hai
    • Types:
      • Chlorenchyma: Chlorophyll hota hai, photosynthesis karta hai
      • Aerenchyma: Aquatic plants mein hota hai, floating mein help karta hai
  2. Collenchyma
    • Living cells, corners par cell wall thicken hoti hai
    • Function: Flexibility aur mechanical support deta hai
    • Location: Leaf stalks, climbers
  3. Sclerenchyma
    • Dead cells, lignin se thickened walls
    • Function: Strength aur hardness provide karta hai
    • Example: Coconut ka husk

Complex Permanent Tissue:

  1. Xylem – Water aur minerals ko roots se poori plant body mein pahuchata hai
    • Components:
      • Tracheids
      • Vessels
      • Xylem Parenchyma
      • Xylem Fibres
  2. Phloem – Food (jaise glucose) ko leaves se poori plant body mein distribute karta hai
    • Components:
      • Sieve tubes
      • Companion cells
      • Phloem Parenchyma
      • Phloem Fibres (sirf yeh dead hote hain, baaki sab living)

✔️ Protective Tissues:

  1. Epidermis
    • Plant ke surface par hoti hai
    • Protection deti hai
    • Aerial parts mein waxy layer (cuticle) hoti hai to prevent water loss
    • Roots mein root hairs hote hain jo water absorb karte hain
    • Leaves mein stomata hote hain (gases exchange aur transpiration ke liye)
  2. Cork / Bark
    • Old stems mein epidermis replace ho jata hai cork se
    • Dead cells se bana hota hai
    • Suberin hota hai walls mein jo waterproof banata hai

🧕 ANIMAL TISSUES

✅ Main Types:

  1. Epithelial Tissue
  2. Connective Tissue
  3. Muscular Tissue
  4. Nervous Tissue

✔️ Epithelial Tissue

Body ke surface ya organs ke covering mein paya jaata hai. Protection, absorption, secretion karta hai.

Types:

  • Squamous Epithelium: Flat cells (lungs, blood vessels)
  • Stratified Squamous: Multiple layers (skin)
  • Cuboidal Epithelium: Cube-like cells (kidney tubules)
  • Columnar Epithelium: Pillar-like (intestine)
  • Ciliated Columnar: Cilia wale cells (respiratory tract)
  • Glandular Epithelium: Secretions karta hai (glands)

✔️ Connective Tissue

Yeh body ke parts ko connect karta hai.

Tissue TypeFunction
BloodTransport karta hai (O2, CO2, food, waste)
BoneBody ka framework, strong and hard
CartilageFlexible support (nose, ear)
LigamentBone to bone connect karta hai
TendonMuscle to bone connect karta hai
AreolarOrgans ko support karta hai, repair karta hai
AdiposeFat store karta hai, insulation deta hai

✔️ Muscular Tissue

Body ke movement mein help karta hai. Isme contractile proteins hote hain.

TypeControlCell shapeLocation
StriatedVoluntaryLong, cylindrical, multinucleateArms, legs
SmoothInvoluntarySpindle-shaped, uninucleateIntestine, blood vessels
CardiacInvoluntaryBranched, uninucleateHeart

✔️ Nervous Tissue

Body mein signal bhejne aur receive karne ka kaam karta hai.

  • Basic unit: Neuron
  • Parts:
    • Cell body (nucleus hota hai)
    • Dendrites (receive signal)
    • Axon (pass signal)

Brain, spinal cord aur nerves isi tissue se bante hain.

🎯 Summary (Kya Seekha?):

  • Tissue = Group of similar cells + common function
  • Plants mein: Meristematic & Permanent (Simple + Complex)
  • Animals mein: Epithelial, Connective, Muscular, Nervous
  • Meristematic cells = dividing; Permanent = specialised function
  • Muscle types = Striated, Smooth, Cardiac
  • Nervous tissue = signals transmit karta hai

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