Epithelial Tissue Flashcards
What is a tissue?
A group of similar cells and binding extracellular matrix joined together
What are the 7 characteristics of epithelium
Cellularity (little extracellular space), cell junctions (for strength and communication), polarity (apical and basal surfaces), sits on basement membrane, avascular, innervated, regeneration
What is the basal region
The base region under underlying tissue
What is the apical region
The free edge of epithelium that you can touch
What is the the basement membrane
Basal lamina and reticular fibers of underlying connective tissue that offers cells a place to anchor via proteins
What are the kinds of cell junctions
Tight junctions, gap junctions, and desmosomes
What is the basal lamina
A sheet of proteins that provides cells a surface to build on
How is the basal membrane connected to the basement membrane
Via reticular protein fibers
What are microvilli
Folds of plasma membrane made of epithelial tissue that maximize surface area for absorption
What are cilla
Whiplike, mobile extensions of cell surface whose internal organization allows them to move in order to move mucus (e.g. in reproductive tissue in the ovum)
What are the functions of epithelial tissue
Secretion (stomach, salivary gland), protection (skin), absorption and diffusion of nutrients or gases (alveoli)
What is the difference between simple and stratified epithelium
Simple is one layer, stratified is multiple layers (new cells made at the basal layer)
What shape is a squamous epithelial cell
Flattened
What shape is a cuboidal epithelial cell
Cube shaped
What shape is a columnar epithelial cell
Tall
What are three shapes of epithelial cells
Squamous, cuboidal, and columnar
How are stratified epithelia named
By the cell shape on the apical surface
What do simple squamous epithelia do and where
Diffusion (lungs), filtration (kidney), secretion (serous membranes)
What do simple cuboidal epithelia do and where
Absorption (kidney), secretion (some glands)
What do simple columnar epithelia do and where
Absorption (GI tract), movement - i.e of mucus because they may or may not be ciliated (lungs), secretion (mucus)
What is pseudostratified columnar epithelium
A single layer of cells sitting on the basement membrane varying in height - usually ciliated - that aids in secretion and movement (mucus of respiratory system)
What do stratified squamous epithelia do and where
They may be keratinized or non-keratinized but used regardless for protection (skin and oral cavity)
What do stratified cuboidal epithelia do and where
Protection (salivary ducts)
What do stratified columnar epithelia do and where
Protection (male urethra), secretion (some glands) - not common
