Epithelial Tissues Flashcards
What are epithelial tissues?
A diverse group of tissues that provides structural and functional barrier between biological compartments
What are the 2 major types of epithelial tissue?
- Surface
- Glandular
What is surface epithelial tissue?
- Covers or lines the body surfaces, tubes and cavities
- Forms boundaries between different environments
What is glandular epithelial tissue?
- Primarily involved in secretion
- Exocrine glands
- Endocrine glands
What are the characteristics of epithelial tissue?
- Continuous sheets of cells tightly bound together
- Supported by a basement membrane
- Epithelial cells are POLARISED:
- Structurally and functionally distinct cell surfaces
- Basal surface attached to (or facing towards) BM
- Apical surface not attached to cells (free)
- Form structural and functional barrier
What are the functions of epithelial tissue?
- Physical protection
- Diffusion
- Absorption
- Secretion
Where in the body does epithelial tissues act as physical protection?
- Skin and oral cavity
Where in the body does epithelial tissues use diffusion?
- Transfer of gases, nutrients and waste between blood and surrounding surfaces
Where in the body does epithelial tissues use absorption?
- Nutrients from GIT
Where in the body does epithelial tissues use secretion?
- Sweat
- Mucus
- Enzymes
What are the 3 main criterial of epithelial tissue that is related to their function?
- Number of layers
- Cell shape
- Specialisations
What are SIMPLE epithelia?
- One layer of cells
- Diffusion/absorption/ secretion
What are STRATIFIED epithelia?
- Two or more layers
- Physical protection against mechanical stress
What are PSEUDOSTRATIFIED epithelia?
- Single layer of cells that appear stratified
- Nuclei are at different heights and not all cells reach apical surface
What is a squamous cell?
- Cells are flat
- Width greater than height