Question

The matrix or ground substance in connective tissues are made up of (a) Thick proteins (b) Elastin fibres (c) Modified polysaccharides (d) Modified triglycerides

Short answer

The matrix or ground substance in connective tissues is primarily made up of (c) Modified polysaccharides.

Step-by-step solution

Understanding Connective Tissues

Connective tissue is one of the four types of biological tissue. It develops from the mesoderm (middle germ layer) and is found throughout the body. It performs a variety of functions, such as providing support and binding different types of tissues together.

Knowing the Composition of Connective Tissues

Connective tissues consist of cells and an extracellular matrix. The cells are dispersed in the matrix. The matrix is made up of fibers (collagen, elastic, and reticular fibers) and ground substance. The ground substance fills the space between the cells and fibers.

Understanding Ground Substance

Ground substance is a clear, colorless, and viscous fluid that fills the gaps between the cells and fibers in the connective tissues. It helps to provide a medium through which nutrients and metabolic wastes can diffuse.

Identifying the Components of Ground Substance

The ground substance is chiefly made up of glycosaminoglycans (GAGs), proteoglycans, and glycoproteins. GAGs are large, linear polymers composed of repeating disaccharides, and they are heavily modified with sulfates. Hence, they are a type of modified polysaccharides.

Key concepts

Extracellular Matrix

The extracellular matrix (ECM) is an essential component of connective tissue. It serves as a scaffold that holds cells together and supports tissue structure. The ECM not only provides structural support but also plays a role in cell communication and regulation of cellular functions.

Within the ECM, you'll find a meshwork of proteins and carbohydrates. This intricate network influences tissue behavior by providing physical cues to the surrounding cells. Types of fibers in the ECM include:

• Collagen fibers: Known for their strength, they provide tensile support.
• Elastic fibers: These fibers grant tissues elasticity, allowing them to stretch and recoil.
• Reticular fibers: Form a supportive mesh for cells and tissues.

Additionally, the ECM helps to regulate the passage of substances between capillaries and cells. This permeability is crucial for supplying nutrients and removing waste products from cells.

The dynamic nature of the ECM makes it more than just a structural entity. It actively guides and influences many cellular processes, such as growth and differentiation.

Ground Substance

Ground substance is a gelatinous component of the extracellular matrix. It fills the spaces in between the cells and fibers, acting as a medium through which substances can diffuse. This fluid-like substance is primarily composed of water, along with an extensive array of carbohydrates and proteins.

Ground substance's composition allows it to serve two main roles:

• Medium for exchange: It facilitates the movement of nutrients and waste products between blood vessels and cells.
• Physical barrier: The viscous nature of ground substance also acts as a protective barrier against mechanistic stress and microbial invasion.

Its gel-like consistency is ideal for maintaining tissue hydration and elasticity. This feature particularly assists connective tissues in their multifaceted functions, ranging from shock absorption to delivery of essential nutrients.

Depending on the tissue type, the precise composition of the ground substance can vary, but its basic function and importance remain constant across different connective tissues.

Glycosaminoglycans

Glycosaminoglycans (GAGs) play a pivotal role in the structure and function of the extracellular matrix. These long, unbranched carbohydrates are made of repeating disaccharide units, and they typically undergo significant sulfation, making them highly negatively charged.

This negative charge allows GAGs to attract water and form a hydrated gel. This property is crucial for resisting compressive forces, which is why GAGs are so abundant in cartilage and other tissues needing resilience.

• Hyaluronic acid: One of the most well-known GAGs, essential for creating a viscoelastic matrix in tissues.
• Chondroitin sulfate: A GAG that provides additional structural integrity, often found in cartilage.
• Heparan sulfate: This GAG is involved in cell signaling and modulation within the ECM.

Beyond their structural roles, GAGs also facilitate communication between cells by binding to signaling molecules and growth factors. Through these interactions, they influence various biological processes, including cell proliferation and differentiation.

Understanding GAGs is key to appreciating how connective tissues can maintain their structural integrity while permitting dynamic interactions within the body.