RBSE Class 9 Science Chapter 6 notes

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RBSE Class 9 Science Chapter 6: Tissues

Introduction to Tissues

• Tissue: A group of cells that are similar in structure and work together to perform a specific function.
  

  

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• Histology: The study of tissues.

Types of Tissues

1. Plant Tissues:
   • Meristematic Tissues:
     • Characteristics: Cells are small, thin-walled, and have dense cytoplasm.
     • Function: Responsible for growth in plants.
     • Types: Apical meristem (found at the tips of roots and shoots), Lateral meristem (found in the vascular cambium and cork cambium).
   • Permanent Tissues:
     • Simple Permanent Tissues:
       • Parenchyma: Thin-walled cells with large intercellular spaces, involved in photosynthesis, storage, and secretion.
       • Collenchyma: Elongated cells with thickened corners, provide mechanical support and flexibility.
       • Sclerenchyma: Thick-walled cells with lignin, provide mechanical strength and support.
     • Complex Permanent Tissues:
       • Xylem: Conducts water and minerals from roots to other parts of the plant. Components include tracheids, vessels, xylem parenchyma, and xylem fibers.
       • Phloem: Transports food materials from leaves to other parts of the plant. Components include sieve tubes, companion cells, phloem parenchyma, and phloem fibers.
2. Animal Tissues:
   • Epithelial Tissue:
     • Characteristics: Cells are closely packed with little intercellular matrix.
     • Function: Protection, absorption, and secretion.
     • Types: Squamous epithelium (thin and flat), Cuboidal epithelium (cube-shaped), Columnar epithelium (tall and column-like).
   • Connective Tissue:
     • Characteristics: Cells are loosely packed with a lot of intercellular matrix.
     • Function: Binding, support, and protection.
     • Types: Areolar tissue (loose connective tissue), Adipose tissue (fat storage), Bone tissue (rigid support), Cartilage (flexible support), Blood (fluid connective tissue).
   • Muscular Tissue:
     • Characteristics: Cells are long and contractile.
     • Function: Movement and locomotion.
     • Types: Skeletal muscle (voluntary movement), Smooth muscle (involuntary movement in internal organs), Cardiac muscle (involuntary movement in the heart).
   • Nervous Tissue:
     • Characteristics: Cells are specialized for impulse conduction.
     • Function: Transmission of nerve impulses.
     • Components: Neurons (nerve cells) and neuroglia (supporting cells).

Important Points to Remember

• Tissues are groups of cells performing similar functions.
  

  

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• Plant tissues include meristematic and permanent tissues.
  

  

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• Animal tissues include epithelial, connective, muscular, and nervous tissues.
• Each type of tissue has specific functions essential for the organism's survival.

These notes provide a comprehensive overview of the different types of tissues in plants and animals, their structures, and functions, as covered in Chapter 6 of the RBSE Class 9 Science textbook.