Extracellular Matrix Signaling and Cell Junctions

All flashcards

What is the extracellular matrix?

It is a network of materials outside animal cells, including proteins such as collagen and carbohydrate-containing proteoglycans. It supports tissues and can help cells communicate with their surroundings.

How can an extracellular matrix signal affect activity inside a cell?

An ECM molecule binds a membrane receptor, changing the receptor’s shape. This can influence microfilaments and trigger signals that affect gene transcription, protein production, and cell activity.

What is the function of a tight junction?

A tight junction seals the space between adjacent animal cells, limiting leakage between them. It is common in epithelial tissues, such as the lining of the urinary bladder.

How do desmosomes connect animal cells?

Cadherins connect neighboring cells and link to intermediate filaments, creating strong, spot-weld-like attachments that help tissues withstand stretching and mechanical stress.

How do gap junctions help coordinate heart muscle cells?

Connexins assemble into connexons that align between neighboring cells to form channels. These channels allow electrical signals to pass between cardiac muscle cells so they can contract in a coordinated way.

Quiz questions

1. Which protein is the most abundant component of the animal extracellular matrix?Answer: Collagen
2. What can occur when an extracellular matrix molecule binds to a cell-surface receptor?Answer: The receptor changes shape and may trigger intracellular signaling.
3. What is the main role of tight junctions between adjacent animal cells?Answer: They seal the space between cells and limit leakage.
4. Which junction helps animal tissues resist stretching by strongly anchoring neighboring cells?Answer: Desmosomes, which connect to intermediate filaments.
5. How do gap junctions support coordinated contraction in cardiac muscle?Answer: They allow electrical signals to pass between neighboring cells.