TOPIC 2 - EPITHELIUM Flashcards
Main type of epithelium that covers outer surfaces of body and lines internal body.
Covering and Lining Epithelium
Main type of epithelium that contains cells specialized for secretion.
Glandular epithelium
3 functions of basal lamina
Structure, organization, filtration
Most apical junction in epithelium that forms bands which complete encircle each cell; membranes of adjacent cells fuse to seal off the intercellular space.
Zona occludens (tight junctions)
This interstitial junction are composed of cadherin and catenin proteins that provide adhesion between adjacent cells; Actin filaments in cytoplasm insert into attachment plaques.
Zona adherens
Spot adhesions between cells. They line up on adjacent cells and has super strong attachment points between cells.
Macula adherens
It attaches epithelial cells to basal lamina.
Hemidesmosomes
Occur almost anywhere along lateral surfaces of epithelial cells and also in other cells such as cardiac muscle cells; has protein channel connections with central pores allowing ions & other small molecules to pass through to adjacent cells to facilitate communication.
Gap junction
Other term for Zonula Adherens
Belt desmosome
5 characteristics of epithelium
- Basal lamina
- Cohesive
- Variation in shape and sizes
- Avascular
- Polarity
What are the protein channels with central pores connecting plasma membranes?
Connexons
This structure plus the cell coat equates to the brush border or striated border of epithelia; its purpose is to increase the surface area for absorption or secretion
Microvilli
The central core of microvilli is made up of ?
Actin microfilaments
Since the microvilli has actin microfilaments, it waves back and forth like cilia. True or False?
False
Long non-motile microvilli found in parts of male reproductive system.
Stereocilia
Much longer than microvilli. Moves back and forth to propel fluid along the epithelial surface.
Cilia
It is a 9+2 configuration of microtubules contained in cilia.
Axoneme
How is covering/lining epithelium categorized?
- Shape of superficial cells
- Number of cell layers
- Presence of specialized structures
Type of epithelia that is more wider than longer and is flattened.
Squamous
Type of epithelia that has the same width and height.
Cuboidal
Type of epithelia that is more longer than wider.
Columnar
Means one layer of cells
Simple
Means two or more layers of cells
Stratified
This term refers to all cells are in contact with basal lamina but not all cells reach lumen.
Pseudostratified
A stratified epithelium that changes in shape in response to stretching; appears cuboidal when relaxed and squamous when stretched.
Transitional
Type of squamous epithelium that lines blood and lymphatic vessels.
Endothelium
Type of simple squamous epithelium lining the serous cavities such as Pleura, pericardium, and peritoneum.
Mesothelium
Duct linings of pancreas has what type of epithelium?
Simple cuboidal epithelium
The epithelium of the small intestine is ?
Simple columnar
This type of epithelia can be found in respiratory with goblet cells and cilia.
Pseudostratified ciliated columnar epithelium
Mucous membranes are composed of what type of epithela?
Stratified squamous epithelium
This type of epithelia can be seen in the linings of larger duct of pancreas.
Stratified cuboidal epithelium
This type of epithelia covers skin that is thin and needs protection,
Keratinized stratified squamous epithelium
This type of epithelia is present in skin areas that are always moist.
Non-keratinized stratified squamous epithelium
What are the 3 types of glandular epithelia?
- Mucous goblet cell
- Exocrine gland
- Endocrine gland
Is mucous goblet cells unicellular or multi-cellular?
Unicellular
This type of glandular epithelia retains connection with epithelial surface; and secretes hormones through ducts
Exocrine gland
This type of glandular epithelia has no connection with surface epithelium; and hormones are secreted through blood.
Endocrine gland
What are the 3 methods of secretion in exocrine glands?
- Merocrine
- Holocrine
- Apocrine
Method of exocrine secretion: Secretory granules leave cells by exocytosis from secretory cells into epithelial-walled ducts and then onto the bodily surface or into the lumen.
Merocrine
Method of exocrine secretion: Entire cell disintegrates to secrete its substance.
Holocrine
Method of exocrine secretion: Portion of secreting cell’s body (apical cytoplasm) is lost during secretion
Apocrine
Give an example of holocrine gland.
Sebaceous gland
Give an example of apocrine gland.
Mammary gland
Give atleast 5 examples of glandular epithelial CELLS.
Note: glandular epithelia is different from glandular epithelial cells.
- Ion-transporting cells
- Serous secretory cells
- Mucous secretory cells
- Neuroendocrine cells
- Myoepithelial cells
This glandular epithelial cells has deep invaginations of basal cell membranes and has its mitochondria located in basal cytoplasm.
Ion-transporting cells
Give an example of ion-transporting cells.
Proximal tubules in kidney.
This glandular epithelial cell has large rounded nucleus and abundant rough ER, Golgi and secretory granules.
Serous secretory cells
What are the examples of serous secretory cells?
- Pancreatic acinar cells
- Serous cells
This glandular epithelial cell has abundant rough ER, Golgi and secretory granules and produce mucins.
Mucous secretory cells
Give the locations of mucous secretory cells?
- mucous cells in stomach
- goblet cells in small and large intestine
- mucous cells in salivary glands
Neuroendocrine cells are localized in the brain. True or False?
False, it is scattered throughout the body.
This glandular epithelial cell has dense secretory granules in cytoplasm that contain polypeptides and/or amines (like epinephrine and norepinephrine).
Neuroendocrine cells
This glandular epithelial cell is spindle-shaped and found in glandular epithelial between basal lamina and basal cytoplasm.
Myoepithelial cells
“Octopus on a rock” gland
Myoepithelial cells
Myoepithelial cell contains actin. True or False?
True
