NCERT Class 9 Science Chapter 6 – Tissues

NCERT Class 9 Science Chapter 6 explains how groups of similar cells combine to form tissues that perform specific functions in multicellular organisms. NCERT Class 9 Science Chapter 6 builds strong conceptual clarity about plant tissues and animal tissues, which is essential for understanding higher biological organization.

The chapter highlights the contribution of Marie François Xavier Bichat (1801), who introduced the term “tissue.” It explains the difference between plant tissues and animal tissues based on growth patterns and functional requirements.

NCERT Class 9 Science Chapter 6 classifies plant tissues into meristematic and permanent tissues, and animal tissues into epithelial, connective, muscular and nervous tissues. It also explains the microscopic structure and function of xylem, phloem, neurons and muscle fibres.

Understanding tissue structure helps students connect cell biology with organ systems in higher classes.

For structured preparation of NCERT Class 9–12 for UPSC, BPSC and State PCS examinations, strengthen your basics with our complete NCERT Book Notes PDF for Class 9-12, available inside the NCERT foundation course level-2.

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1. Introduction

• In multicellular organisms, similar cells group together to perform a specific function, forming a tissue.
• The term tissue was introduced by Marie François Xavier Bichat (1801).
• In unicellular organisms like Amoeba, a single cell performs all life functions.
• In multicellular organisms, division of labour occurs, increasing efficiency.
• Plants and animals differ in tissue organisation due to difference in growth patterns and mobility.

2. Differences between plant and animal tissues

• Plant tissues are generally less complex than animal tissues.
• Most plant tissues are dead and provide mechanical strength.
• Animal tissues are mostly living and specialized for movement and coordination.
• Growth in plants is restricted to specific regions, whereas in animals growth occurs throughout body.

3. Plant tissues

• Plant tissues are classified into meristematic tissue and permanent tissue.
• Classification is based on capacity to divide.
• Meristematic tissues are actively dividing cells.
• Permanent tissues arise from meristematic tissues after differentiation.

4. Meristematic tissue

• Cells divide continuously and are small with dense cytoplasm.
• Thin cell walls and prominent nucleus.
• Vacuoles absent or very small.
• Responsible for growth in plants.
• Found in specific regions of plant.

5. Types of meristematic tissue

• Apical meristem located at root and shoot tips, responsible for increase in length.
• Intercalary meristem present at base of leaves or internodes, helps in elongation.
• Lateral meristem (cambium) increases girth of stem and root.
• Diagram shows apical meristem at tip and lateral meristem along sides.

6. Permanent tissue

• Formed from meristematic cells after differentiation.
• Cells lose ability to divide.
• Cells become larger and develop vacuoles.
• Divided into simple permanent tissue and complex permanent tissue.

7. Simple permanent tissues

• Made of similar type of cells performing similar function.
• Three types: Parenchyma, Collenchyma, Sclerenchyma.
• Provide support and storage.

8. Parenchyma

• Living cells with thin cell walls.
• Cells loosely packed with intercellular spaces.
• Stores food and water.
• Present in soft parts like cortex and pith.
• In aquatic plants, modified as aerenchyma for buoyancy.
• Parenchyma with chlorophyll called chlorenchyma.

9. Collenchyma

• Living cells elongated with uneven thickening at corners.
• Provides flexibility and mechanical support.
• Found in leaf stalks and below epidermis of dicot stems.
• Allows bending without breaking.

10. Sclerenchyma

• Dead cells with thick lignified walls.
• Provide mechanical strength.
• Cells are either fibres or sclereids.
• Found in seed coats and nutshells.
• Diagram shows thick walls and narrow lumen.

11. Complex permanent tissues

• Made of different types of cells working together.
• Two types: Xylem and Phloem.
• Responsible for transport.

12. Xylem

• Conducts water and minerals from roots to leaves.
• Composed of tracheids, vessels, xylem fibres, xylem parenchyma.
• Mostly dead cells except xylem parenchyma.
• Provides mechanical support.
• Diagram shows upward movement of water.

13. Phloem

• Conducts food from leaves to other parts.
• Composed of sieve tubes, companion cells, phloem fibres, phloem parenchyma.
• Sieve tubes are living cells.
• Food movement is bidirectional.

14. Protective tissues

• Epidermis forms outer covering.
• Covered by waxy layer called cuticle.
• Contains stomata for gas exchange.
• Cork cells are dead and protective.

15. Animal tissues

• Classified into Epithelial, Connective, Muscular and Nervous tissues.
• Animal tissues are more specialized.
• Provide movement and coordination.

16. Epithelial tissue

• Covers body surfaces and cavities.
• Cells tightly packed with no intercellular spaces.
• Types include Squamous, Cuboidal, Columnar, Ciliated and Glandular epithelium.
• Protects, absorbs and secretes.

17. Connective tissue

• Connects and supports organs.
• Cells embedded in matrix.
• Types include Areolar, Adipose, Bone, Cartilage, Blood.
• Blood is fluid connective tissue.

18. Muscular tissue

• Responsible for movement.
• Three types: Striated, Smooth and Cardiac muscle.
• Striated muscle voluntary.
• Smooth muscle involuntary.
• Cardiac muscle found in heart.

19. Nervous tissue

• Made of neurons.
• Transmits impulses.
• Neuron consists of cell body, dendrites and axon.
• Controls coordination.

20. Microscopic structural details

• Parenchyma shows thin walls and spaces.
• Collenchyma shows corner thickening.
• Sclerenchyma shows thick lignified walls.
• Xylem vessels appear tubular.
• Neurons show long axon and branching dendrites.

21. Diagram explanation

• Plant tissue diagram highlights arrangement of cells in parenchyma and collenchyma.
• Xylem diagram shows upward arrow indicating water transport.
• Phloem diagram shows bidirectional arrows.
• Animal tissue diagram shows layered epithelial cells.
• Muscle diagram shows striations in skeletal muscle.

22. Conclusion

• Tissues allow division of labour in multicellular organisms.
• Plant tissues provide support and transport.
• Animal tissues provide movement and coordination.
• Structural differences reflect functional specialization.

23. Exam oriented facts

• Bichat (1801) – Introduced term tissue.
• Apical meristem – Responsible for increase in length.
• Lateral meristem – Responsible for increase in girth.
• Parenchyma – Living storage tissue.
• Sclerenchyma – Dead strengthening tissue.
• Xylem – Water conducting tissue.
• Phloem – Food conducting tissue.
• Epithelial tissue – Protective covering tissue.
• Neuron – Structural and functional unit of nervous tissue.
• Cardiac muscle – Involuntary muscle present in heart.

Understanding NCERT Class 9 Science Chapter 6 is essential for learning how multicellular organisms achieve division of labour through tissue specialization.

This chapter forms the foundation for higher topics such as plant anatomy, human physiology, circulatory system and nervous coordination.

For school examinations, students must focus on types of meristematic tissues, differences between simple and complex permanent tissues, structure of xylem and phloem, and classification of animal tissues.

For competitive examinations like NEET, NCERT Class 9 Science Chapter 6 provides essential clarity about tissue organization and structure-function relationships.

Continue reading NCERT Class 9 Science Chapter 7 – Motion to understand the basic principles of mechanics and kinematics.

FAQs

Q1. What is NCERT Class 9 Science Chapter 6 about?
It explains the concept of tissues, types of plant tissues and animal tissues, and their structure and functions in multicellular organisms.

Q2. What are the types of plant tissues?
Plant tissues are classified into meristematic tissues (apical, intercalary and lateral) and permanent tissues (simple and complex tissues like xylem and phloem).

Q3. What are the four types of animal tissues?
Animal tissues are epithelial, connective, muscular and nervous tissues, each performing specialized functions.

Q4. What is the function of xylem and phloem?
Xylem transports water and minerals from roots to other parts of the plant, while phloem transports food from leaves to other parts.

Q5. Why is NCERT Class 9 Science Chapter 6 important for competitive exams?
It builds foundational understanding of tissue organization, which is essential for advanced biology topics in NEET and other medical entrance examinations.

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