The stroma is a component of connective tissue that forms the supportive framework or scaffold in various organs and tissues within the body. It is composed of several elements, including:
- Extracellular matrix (ECM): The ECM is a complex network of proteins and carbohydrates that provide structural support and stability to the surrounding cells. Key components of the ECM include collagen, elastin, fibronectin, and proteoglycans.
- Fibroblasts: As mentioned earlier, fibroblasts are cells that produce and maintain the ECM. They play a crucial role in maintaining the structural integrity of the stroma by producing its key components.
- Blood vessels: Blood vessels are essential for providing nutrients and oxygen to the cells within the tissue, as well as removing waste products. The network of blood vessels within the stroma helps to maintain the overall health and function of the tissue.
- Immune cells: Immune cells, such as macrophages and lymphocytes, are often present within the stroma. They play a role in defending the tissue against pathogens and in modulating inflammation and tissue repair.
- Nerve fibers: Nerve fibers can be found within the stroma, providing a means of communication between the tissue and the nervous system.
- Other supporting cells: Depending on the specific tissue, the stroma may also contain other types of supporting cells, such as pericytes (which help stabilize blood vessels) or adipocytes (fat cells).
The stroma is crucial for maintaining the overall integrity and function of tissues and organs. In some cases, such as in tumors, the stroma can become altered or dysregulated, contributing to disease progression and complicating treatment efforts.