Connective Tissue - Biology PDF

**[Connective Tissue]** **[Learning outcomes ]** **1- State the functions and characteristics of connective tissue:** - **Functions**: - **Support**: Provides structure to tissues and organs (e.g., bones, ligaments). - **Protection**: Involves immune defense, wound healing...

**[Connective Tissue]** **[Learning outcomes ]** **1- State the functions and characteristics of connective tissue:** - **Functions**: - **Support**: Provides structure to tissues and organs (e.g., bones, ligaments). - **Protection**: Involves immune defense, wound healing, and cushioning of organs (e.g., adipose tissue around kidneys). - **Transport**: Facilitates movement of nutrients, water, and waste products (e.g., blood transports oxygen, nutrients). - **Insulation & Storage**: Fat tissue stores energy and helps regulate body temperature. - **Characteristics**: - Connective tissue is made of **cells**, **fibres**, and **extracellular matrix (ECM)**, with the ECM providing strength, structure, and flexibility. **2- Name and describe the non-cellular substrate (extracellular matrix) of connective tissue:** - The **extracellular matrix (ECM)** is a **gel-like substance** composed of water, proteins, glycoproteins, and glycosaminoglycans (GAGs). It surrounds and supports the cells within connective tissue. - It provides structural integrity and mediates the transportation of nutrients and waste. - The ECM can have different properties depending on the tissue type (e.g., calcified in bones, flexible in cartilage). **3- List and describe the cells of connective tissue:** - **Fixed Cells**: - **Fibroblasts**: Produce and maintain fibres (collagen, elastic) and ECM. - **Adipocytes**: Store fat for energy, insulation, and cushioning. - **Macrophages**: Engulf pathogens and dead cells, aiding in immune defense. - **Mast Cells**: Release histamine during allergic reactions, contributing to inflammation. - **Transient Cells**: - **Plasma Cells**: Produce antibodies to fight infections. - **Eosinophils**: Combat parasites and participate in allergic responses. **4- List and describe the fibres of connective tissue:** - **Collagen Fibres**: Thick fibres that provide tensile strength and resist stretching. They are abundant in tendons and ligaments. - **Elastic Fibres**: Thinner fibres that allow tissues to stretch and recoil. Found in skin, lungs, and arteries. - **Reticular Fibres**: Thin, branching fibres forming a mesh-like structure. They support soft tissues, such as the spleen and lymph nodes. **5- Outline and classify the types of connective tissue:** - **Connective Tissue Proper**: - **Loose Connective Tissue**: - **Areolar**: Binds skin to underlying structures, supports blood vessels. - **Adipose**: Stores fat, insulates the body, cushions organs. - **Reticular**: Supports lymphoid organs (e.g., spleen, lymph nodes). - **Dense Connective Tissue**: - **Regular**: Parallel collagen fibres, providing strength in tendons and ligaments. - **Irregular**: Densely packed fibres in random directions, providing strength in the dermis. - **Elastic**: Contains mostly elastic fibres, allowing stretch and recoil in arteries and lungs. - **Specialized Connective Tissue**: - **Cartilage**: Hyaline, fibrocartilage, elastic. - **Bone**: Compact and spongy bone. - **Blood**: Transports oxygen, nutrients, and waste; also involved in immune defense and clotting​