what are the two components of a tissue?
cells and matrix
what is epithelial tissue?
-sheets of cells that cover every exposed body surface and line internal cavities and passageways that are avascular, organized in sheets that are highly regenerative
what are the 4 functions of epithelial tissue?
1) protection - through regeneration
2) controls permeability
- blood vessel = single layer of epithelial tissue
3) sensation (neuroepithelial - cells responsible for special senses)
4) specialized secretions - glandular epithelium
what is the function of cilia?
-these are longer than microvilli and help move stuff
what is the function of microvilli?
-line passageways where we need more absorption (increase surface area)
which structures are affected in smokers lungs? Crohn’s disease?
smoker: cilia (hard to move stuff out of respiratory tract)
Crohn’s: microvilli (absorption)
how are epithelial tissues classified?
1) layering
- simple
- stratified
- pseudo-stratified
2) shape of cells
- squamous
- cuboidal
- columnar
squamous cell
where is the nucleus of a columnar cell?
usually at basement membrane
how do we classify the type of epithelial cell?
by the top (superficial) layer
cuboidal cell
columnar cell
-lines almost entire length of digestive tract (simple columnar) except for mouth and anus (stratified squamous)
give examples of simple columnar cell-type tissues
-stomach, intestinal tract, uterine tubes, excretory ducts
give examples of stratified columnar cell-type tissues
-pharynx, urethra, anus, excretory ducts
pseudo stratified cell
transitional epithelium
in what 3 ways of glandular epithelia classified?
1) types of secretions
2) structure of gland
3) method of secretion
what are the 2 types of glandular secretions?
1) exocrine
2) endocrine
exocrine glands
_____ epithelium can be keratinized or nonkeratinized
stratified squamous
keratin - def
tough, fibrous protein component of nails, hair, calluses, and the general integumentary surface
keratinized - def
containing large quantities of keratin
_____ stratified squamous epithelium are tough and water resistant
keratinized
_____ stratified squamous epithelium resist abrasion but must be kept moist
nonkeratinized