Epithelial Tissue Flashcards
Two subtypes of epithelial tissue
- covering and lining
- glandular
Characteristics of epithelial tissue
- Cover and line
- Little to no matrix (material outside of cells)
3.all avascular and lie on basement membrane
4.Cells packed close together
5.Has to be connective vascular tissue keeping epithelial alive by diffusion - High regeneration rate
Basement membrane
-lie between epithelial tissue (avascular) and connective tissue (vascular)
Simple Tissue
-one layer (single layer of cells does not protect)
Ex: stomach has one layer, filtering blood, gas exchange in lungs
Stratified Tissue
- more than 1 layer (more for protection than diffusion of materials)
EX: vagina, inside of mouth, outer layer of skni
Squamous
-flat and scaly
Cuboidal
-cube shape
Columnar
-can be ciliated or non ciliated
Classification of Simple tissue
- Simple squamous
- Simple cuboidal
- Simple columnar (ciliated)
- Simple columnar (non-ciliated)
- Pseudostratified
Classification of Stratified tissue
- Stratified squamous
- Stratified cuboidal
- Stratified columnar
- Transitional
Simple Squamous epithelium
-Closely packed cells, no matrix, avascular, one layer
Function: Cover and line, also exchange of materials through diffusion
Location: Air sacs in the lungs, capillaries
*most vulnerable tissue in the body
Simple cuboidal epithelium
- closely packed cells, no matrix, avascular, no matrix, one layer
Function: Cover and line, also exchange through diffusion (filtration and secretion)
Location: in kidney tubules, ducts and secretory proteins of small glands and ovary surfaces
*Most filter tubules are made of this
Simple columnar epithelium (non-ciliated)
-single layer of “tall cells”, may include mucous secreting goblets, no matrix, avascular, no cilia, closely packed cells
Function: Cover and line, allows for diffusion b/c one layer thick (absorption)
Location: lining of the stomach and small intestine
* never ciliate anything in the digestive tract
Simple columnar epithelium (ciliated)
-single layer of cells, closely packed together, no matrix, avascular, cilia
Function: absorption, secretion of mucus, cilia propels mucus
Location: small bronchi, uterine tubes and some region of uterus
Pseudostratified epithelium
-false single layer, closely packed, no matrix, three types of cells (small, columnar, and goblet, ciliated)
-every single cell touches the basement membrane
Function: covers and lines, production of mucus, and propulsion of mucus by cilia, protection of air sacs
Location: Lining of the trachea
Stratified squamous epithelium
-several layer of cells, surface cells are flat, cells on basement membrane living undergo mitosis, cells furthest from basement are dead, no matrix, closely packed cells, avascular
Function: covers and lines plus protection due to layers
Location: epidermis of skin, lining of oral cavity
* two types of this one that produces keratin (skin) and one that does not (mouth)
Keratin
-protein, makes stratified squamous epithelial layer tough
Keratinocytes
-makes keratin
Stratified cuboidal epithelium
-rare type of tissue composed of cuboidally shaped cells arranged in multiple layers
-protects areas such as the ducts of sweat glands, mammary glands, and salivary glands
-provide protection, excretion, secretion
Stratified columnar epithelium
-rare type of tissue composed of column shaped cells in multiple layers
-found in the conjunctiva, pharynx, anus, and male urethra. It also occurs in embryo
-provide protection and secretion
Transitional epithelial tissue
-resembles stratified squamous and cuboidal, basal cells, cuboidal, columnar. Surface cells dome shape depending on degree of organ stretch
Function: stretches readily, permits stored urine to distend urinary organ
Location: only found in the urinary bladder
Gland
-make some product for the body
-body needs it
-gland in connective tissue but still follows epithelial rules
-the lining of a gland is epithelial tissue
-classified by where they release product and number of cells
Exocrine gland
-has a duct where the product is made and pours out of the duct (released)
Function: secrets substances onto body surfaces (skin) or body cavities
Location: liver, pancreas, mucous, sweat, oil, and salivary glands
Endocrine gland
-product is made and crosses into the blood vessels (hormones always) they are ductless
Function: secretes hormones by exocytosis directly into extracellular space
-most are compact multicellular organs
Location: in digestive tract lining, brain
*not all endocrine glands are made of epithelial tissue
*they are very bloody (risk for surgery)
Ex: pituitary gland , makes hormones for ovaries
unicellular exocrine gland
one cell big
-are mucous and goblet cells
-sprinkled in the lining of intestinal, respiratory tract
multicellular exocrine gland
-contain a duct and a secretory unit
-classified by structure and mode of secretion
-can be simple or compound
holocrine
some multicellular exocrine glands function in
-accumulate products inside until they rupture, they include the synthesized products plus dead cell fragments
- “holo” = whole
-ex: sebaceous oil glands
-constantly have to be repaired
-cancers can cause these to stop mitosis
merocrine
-secrete their products by exocytosis as they are produced, have Golgi bodies to package. produce, and leave cells
-most glands function this way
ex: gastric, salivary glands, sweat glands, pancreas
apocrine
-accumulate their products but only just beneath the free surface, the apex of the cell pinches off releasing the secretory granules and small amount of cytoplasm
-cell repairs its damage and repeats the process
-ex: mammary glands
sudoriferous glands
-sweat glands can have two functions on apocrine and another eccrine
-apocrine glands are the ones in the armpits, groin. They make you smell
-eccrine glands function is important for temp regulation of the body
