Which of the following is a main characteristic of epithelial tissues?

• A. They are composed primarily of extracellular matrix.
• B. They have a high degree of vascularization.
• C. They have a free surface exposed to the environment or an internal space.
• D. They are loosely packed with cells.

Answer: (C)

Verified step by step guidance

1. Understand the basic characteristics of epithelial tissues: Epithelial tissues are one of the four main types of tissues in the body, and they serve as coverings or linings of surfaces and cavities.
2. Identify the key feature of epithelial tissues: A defining characteristic of epithelial tissues is that they have a free surface that is exposed to either the external environment or an internal space, such as the lumen of an organ.
3. Differentiate epithelial tissues from other tissue types: Unlike connective tissues, epithelial tissues are not primarily composed of extracellular matrix. Instead, they are tightly packed with cells.
4. Consider the vascularization of epithelial tissues: Epithelial tissues are generally avascular, meaning they do not have a high degree of vascularization. They rely on diffusion from underlying tissues for nutrients.
5. Recognize the arrangement of cells in epithelial tissues: Epithelial cells are closely packed together, forming continuous sheets, which is contrary to the statement that they are loosely packed.