Epithelial Tissue Quizlet?

Epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue, and nervous tissue. It covers the body surfaces, both inside and out, and forms glands. Epithelial tissues serve various functions, including protection, absorption, filtration, secretion, and sensation.

Here are some key points about epithelial tissue:

1. **Cellularity:** Epithelial tissues are composed of closely packed cells with little extracellular matrix between them.

2. **Polarity:** Epithelial cells have an apical (upper) surface and a basal (lower) surface. The apical surface is exposed to the external environment or internal body space, while the basal surface is attached to a basement membrane.

3. **Attachment:** Epithelial cells are attached to a basement membrane, which is a thin, extracellular layer that provides structural support.

4. **Avascularity:** Most epithelial tissues lack blood vessels. Nutrients and oxygen diffuse from the underlying connective tissue.

5. **Regeneration:** Epithelial tissues have a high regenerative capacity. They can rapidly divide and replace damaged or lost cells.

6. **Classification:** Epithelial tissues are classified based on the number of cell layers and the shape of the cells. Common types include simple squamous, simple cuboidal, simple columnar, stratified squamous, stratified cuboidal, stratified columnar, and pseudostratified columnar epithelium.