Question

The extracellular matrix (ECM) is partly formed by some types of connective tissue cells and a. contains fibrous proteins that provide structural support to cells. b. provides a scaffolding for the cells. c. plays a role in cellular communication. d. does all of the above. e. does a and b only.

Short answer

The correct answer is d. The extracellular matrix (ECM) does all of the above.

Step-by-step solution

Evaluate statement a

The ECM does contain fibrous proteins that provide structural support to cells. This allows the cells to maintain their shape and integrity. Therefore, statement a is correct.

Evaluate statement b

The ECM also provides a scaffolding for the cells. This is what allows tissues to maintain their structure and for cells to stay in their appropriate locations. Therefore, statement b is also correct.

Evaluate statement c

The ECM does have a role in cellular communication. It allows cells to interact with one another and communicate via various signaling molecules. Therefore, statement c is also correct.

Determine final answer

Since statements a, b, and c are all correct descriptions of the roles of the ECM, the correct answer is d. The ECM does all of the above things listed.

Key concepts

Connective Tissue Cells

Connective tissue cells are central to the formation and maintenance of the extracellular matrix (ECM), a complex network of proteins and molecules that provide much-needed support for tissue integrity. These cells, including fibroblasts, osteoblasts, and chondroblasts, are specialized to secrete the fibrous proteins such as collagen and elastin, which reinforce the strength and elasticity of tissues. The ECM formed by these cells is not static; it's continuously remodeled, allowing tissues to adapt to different physical stresses.

For example, fibroblasts are notorious for their role in wound healing. They migrate to the site of injury, proliferating and synthesizing new ECM to repair the damaged tissue. Without the crucial contributions of connective tissue cells, the ECM would fail to provide the essential structural support necessary for cell function and survival, leading to compromised tissue architecture.

Cellular Communication

Cellular communication within the ECM is a sophisticated process facilitated by the matrix's unique composition and structure. It's not just the physical scaffolding that matters, but also the biochemical signals it harbors. Proteins within the ECM, such as integrins and fibronectin, bind to receptors on cell surfaces, setting off a cascade of signaling pathways. This complex interaction orchestrates various cell functions, including growth, migration, and differentiation.

The ECM's role in cellular communication extends to the coordination of cell behavior in developmental processes and tissue repair. For instance, during embryogenesis, the ECM guides cells to their proper locations, ensuring the correct formation of tissues and organs. Disruptions in these signaling pathways can lead to developmental abnormalities or diseases. The communication facilitated by the ECM is indispensable for maintaining homeostasis and responding to environmental changes.

Structural Support

The structural support provided by the ECM is fundamental to tissue architecture and integrity. This matrix acts as a scaffold that not only maintains the three-dimensional structure of tissues but also withstands and distributes mechanical forces. Fibrous proteins such as collagen impart tensile strength, enabling tissues like skin, tendon, and bone to resist stretching forces. Elastin, another ECM component, allows tissues to resume their shape after being deformed.

Moreover, the ECM's supportive role is not limited to mechanical strength. It also acts as a filter for substances that move between different tissues and plays a significant role in wound healing and tissue regeneration. By adjusting its composition and density, the ECM can selectively permit or restrict the passage of cells and molecules, contributing to the dynamic control of tissue environments. Its ability to provide structural support while dynamically responding to physiological needs highlights the ECM's multifaceted role in the body.