Animal Tissues - Biology Short Notes 📚

The animal kingdom exhibits a remarkable diversity of life forms, from the single-celled amoeba to the majestic blue whale. This complexity arises from the organization of cells into specialized tissues, each with a unique structure and function. These tissues, in turn, combine to form organs, organ systems, and ultimately the entire organism.

Introduction:

➡️ Multicellular animals, from the tiniest insects to majestic whales, are composed of trillions of microscopic building blocks called cells.

➡️ These cells are grouped together based on their structure and function to form specialized tissues, which are the foundation of all organs and systems within the animal body.

➡️ In this article, we will explore the four main types of animal tissues: epithelial, connective, muscle, and nervous tissue.

1. Epithelial Tissue: Covering and Lining

Key Characteristics:

➭ Covers the body’s surface (skin) and lines its organs and cavities (lining of the digestive tract, lungs).

➭ Forms a protective barrier against pathogens and regulates the passage of substances (absorption in the intestines).

➭ Tightly packed cells with minimal intercellular space for efficient barrier function.

➭ Classified based on the number of cell layers (simple or stratified) and cell shape (squamous, cuboidal, columnar).

• Skin
• Lining of the digestive tract, respiratory system, and urinary system
• Glands (sebaceous, sweat)

2. Connective Tissue: Binding and Support

Key Characteristics:

➭ Provides support, structure, and connection to other tissues and organs (bones, tendons, ligaments).

➭ Contains a diverse range of cells and a non-living matrix that varies in consistency (loose connective tissue, dense connective tissue, specialized connective tissue).

➭ Offers flexibility (ligaments) or rigidity (bone) depending on the specific type.

Includes several specialized forms:

Bone: Provides rigid support and mineral storage (skeleton)

• Bones
• Cartilage (ears, nose, joints)
• Tendons (connect muscles to bones)
• Ligaments (connect bones to bones)
• Blood
• Adipose tissue (fat)

3. Muscle Tissue: Movement and Locomotion

Key Characteristics:

➭ Responsible for movement, contraction, and propulsion (skeletal muscles for voluntary movement, smooth muscles for involuntary actions like digestion).

➭ Highly specialized cells containing contractile proteins (actin and myosin) that generate force.

Classified into three main types:

• Skeletal muscles (biceps, triceps, leg muscles)
• Smooth muscles (muscles in the digestive tract, blood vessels)
• Cardiac muscle (heart muscle)

4. Nervous Tissue: Communication and Control

Key Characteristics:

Responsible for receiving, processing, and transmitting information throughout the body, coordinating all bodily functions.

Composed of two main cell types:

Neurons: Specialized cells with long extensions (axons and dendrites) for transmitting electrical signals (nerve impulses).

Glial cells: Support and protect neurons, maintain the nervous system’s environment.

Forms the brain, spinal cord, nerves, and sensory organs.

• Brain
• Spinal cord
• Nerves
• Sensory organs (eyes, ears, nose, taste buds, touch receptors)

Animal Tissues — (Handwritten Notes)

Originally published at https://www.vhtc.org.