Lecture on Tissues - Biology

Introduction

• Focus on exam-relevant points from NCERT.
• Review of previous chapter on cells and their components.
• Today's chapter: Tissues.

Overview

• Plant tissues
• Animal tissues

Plant Tissues

Types of Plant Tissues

1. Meristematic Tissues
   • Types: Apical, Intercalary, Lateral
   • Functions: Growth in length (apical and intercalary), growth in thickness (lateral).
2. Permanent Tissues
   • Types: Simple (Parenchyma, Collenchyma, Sclerenchyma), Complex (Xylem, Phloem).

Detailed Study of Plant Tissues

• Parenchyma: Most common, functions include storage, photosynthesis, and support.
• Collenchyma: Provides flexible support, found in stems and leaves.
• Sclerenchyma: Provides rigid support, found in hard parts like seed coats and nuts.
• Xylem: Transports water and minerals, contains tracheids, vessels, fibers, and parenchyma.
• Phloem: Transports food, contains sieve tubes, companion cells, fibers, and parenchyma.

Protective Tissues

• Epidermis: Outermost layer, protection, and prevention of water loss.
• Cork: Found in the outer bark, protective, and prevents water loss.

Animal Tissues

Types of Animal Tissues

1. Epithelial Tissue
   • Functions: Covers and protects body surfaces and organs.
   • Types: Squamous, Cuboidal, Columnar, Ciliated, Glandular.
2. Connective Tissue
   • Types: Blood, Bone, Cartilage, Areolar, Adipose, Tendons, Ligaments.
   • Functions: Supports, connects, and binds together other tissues.
3. Muscular Tissue
   • Types: Striated (Skeletal), Smooth, Cardiac.
   • Functions: Movement and locomotion.
4. Nervous Tissue
   • Composed of neurons.
   • Functions: Transmission of impulses.

Detailed Study of Animal Tissues

• Epithelial Tissue: Covers body surfaces, lines cavities, protective and absorptive functions.
  • Simple Squamous: Flat cells, functions in filtration and diffusion.
  • Stratified Squamous: Multiple layers, protective, found in the skin.
• Connective Tissue:
  • Blood: Fluid connective tissue, transports gases, nutrients, waste.
    • Components: RBCs, WBCs, Platelets, Plasma.
  • Bone and Cartilage: Rigid and flexible support, respectively.
  • Tendons and Ligaments: Connects muscle to bone and bone to bone.
  • Areolar and Adipose: Fills spaces and stores fat.
• Muscular Tissue:
  • Striated Muscle: Voluntary, attached to bones, striped appearance.
  • Smooth Muscle: Involuntary, found in internal organs.
  • Cardiac Muscle: Heart muscle, involuntary, striated.
• Nervous Tissue:
  • Neurons: Specialized cells transmitting nerve impulses.

Differences in Tissues

• Meristematic vs Permanent Tissues: Permanent tissues lose the ability to divide.
• Types of Epithelial Tissues:
  • Squamous: Thin and flat.
  • Cuboidal: Cube-shaped.
  • Columnar: Column-like.
  • Ciliated: Hair-like structures on the surface.
  • Glandular: Specialized for secretion.
• Types of Muscular Tissues:
  • Striated: Voluntary and striped.
  • Smooth: Involuntary and non-striated.
  • Cardiac: Heart muscle, involuntary, and faintly striated.
• Types of Connective Tissues:
  • Blood: Fluid matrix with cells.
  • Bone: Matrix hardened with calcium and phosphorus.
  • Cartilage: Flexible matrix.
  • Tendons and Ligaments: Connective.
  • Areolar and Adipose: Fills and stores.
• Function of Nervous Tissues: Neurons, communication, and transmission of signals.

Exam Focused Questions

1. Dead Cells in Tissues: Sclerenchyma.
2. Growth in Stem Thickness: Lateral meristem.
3. Absorption in Intestines: Columnar epithelium.
4. Bone to Bone Connection: Ligament.
5. Involuntary Muscles: Smooth and cardiac muscles.
6. Structural and Functional Unit of Nervous System: Neuron.

Conclusion

• Detailed overview of plant and animal tissues.
• Importance of different types of tissues and their specific functions.
• Focus on exam-relevant information from NCERT.