Animal Tissues Overview

Animal Tissues

• Tissues are specialized cells working together for specific functions.
• Functions include protection, support, movement, and communication.

Types of Tissues

1. Epithelial Tissue

• Function: Protects underlying tissues, absorbs nutrients, secretes substances (enzymes, hormones), filters waste, and protects against damage (mechanical, chemical, dehydration, pathogens).
• Types:
  • Simple Squamous: Single, thin, flat cells; found in blood vessels, alveoli, and serous membranes; used for diffusion, transport, and filtration.
  • Simple Cuboidal: Single, cube-shaped cells; found in kidney linings, gland ducts, and ovary surfaces; used for secretion and absorption.
  • Simple Columnar: Single, tall, column-shaped cells; found in the stomach, intestines, and gallbladder; used for secretion, absorption, and lining protection.
  • Stratified Squamous: Multi-layered, flat cells; found in the mouth, esophagus, vagina, and skin; act as a barrier against abrasion and infection.
  • Stratified Cuboidal: Multi-layered, cube-shaped cells; found in sweat, salivary, and mammary glands; used for secretion and absorption.
  • Pseudostratified Columnar: Single-layered, tall cells appearing layered due to varying nuclei positions; found in respiratory tract; used for secretion, absorption, and protection.
  • Transitional: Specialized cells that change shape (stretch); found in urinary bladder and ureters; enable stretching and expansion.

2. Connective Tissue

• Function: Fills spaces, connects different tissues, cushions organs.
  • Characterized by flexibility and firmness.
• Types:
  • Loose: Flexible, web-like cells in a protein matrix; supports, cushions & binds.
  • Dense: Densely packed collagen fibers; provides strength to tendons, ligaments, and fascia.
  • Adipose: Cells (adipocytes) that store fat (triglycerides); provides energy, insulation, and cushioning.
  • Blood: Composed of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes); performs transportation, immunity, and clotting functions.
  • Cartilage: Firm tissue with chondrocytes embedded in collagen fibers; cushions joints, reduces friction.
  • Bone: Rigid tissue with osteocytes in a matrix of collagen fibers and calcium phosphate; provides structural support and protection.

3. Muscle Tissue

• Function: Enables movement.
• Types:
  • Skeletal: Striated, long fibers; voluntary movement.
  • Smooth: Spindle-shaped, non-striated; involuntary movement of organs and blood vessels.
  • Cardiac: Branched fibers with intercalated discs; rhythmic contractions of the heart.

4. Nervous Tissue

• Function: Coordinates body functions via nerve impulses.
• Types:
  • Neurons: Transmit nerve impulses.
  • Neuroglia: Supporting cells that provide nutrients and protection to neurons.

Tissue Regeneration and Repair

• Injury triggers tissue repair.
• Inflammation brings immune cells and nutrients.
• Regeneration involves stem cell and existing cell activity.
• Scar formation fills gaps with fibrous tissue.

Tissue Disorders and Diseases

• Cancer: Uncontrolled cell growth.
• Inflammation: Long-term damage.
• Degenerative disorders: Progressive loss of tissue function (e.g., arthritis).
• Infections: Cause tissue damage and illness.

This quiz covers the different types of animal tissues, focusing on epithelial tissue and its various forms and functions. Gain insight into how these tissues protect, absorb, and provide essential functions within the body. Perfect for students studying biology or anatomy.