The Tissues of the Human Body: Epithelia Flashcards
(34 cards)
How are epithelial cells arranged?
Single continuous sheet or multiple continuous sheets.
Where are the tight junctions located and what is it’s function?
Located at the apical side and they join the adjacent cytoskeleton of the cell by creating a seal which maintains cell polarity.
Where are the tight junctions found?
Stomach, intestines and bladder. We know this because it seals organs that have fluid in them.
What type of proteins are Occludins and Claudins?
Transmembrane proteins meaning they span across the membrane.
What is another name for adherens junction?
Belt desmosomes
What adherens junctions do and where are they located?
Prevent cell seperation from tension forces and more basal than tight.
Where are desmosomes located?
Lateral walls
Main function of desmosomes
Resist shearing force s
Where are desmosomes found?
Commonly bonded to muscle cells (cardiac cells) and skin epithelium to prevent the heart from pulling apart.
What are the proteins that make up gap junctions and what is the function of a gap junction.
6 connexins make up a half connexon (hemichannel)! 1 hemicannel joins with another hemichannel. 2 hemichannel make up a gap junction. Cell communication
What is a junctional complex?
Combination of adherens, desmosomes, and tight junctions.
Where are the hemidesmosones located?
Basal surfaces only
What do the basal lamina and reticular lamina contain?
- Basal = collagen,
laminin, other proteoglycans,
glycoproteins - Reticular = fibrous proteins such as
fibronectin, collagen
List the 4 functions of basement membrane
- Supports the overlying epithelium
- Provides a surface for epithelium cells to migrate on top of
- Physical barrier
- Filtration barrier for kidneys
What are types of covering epithelium and what do they do?
- Outer lining which covers skin and some internal organs
- Inner lining covers the blood vessels, ducts and body
cavities, and the interior of the
respiratory, digestive,
urinary and reproductive systems
Function of simple squamous epithelial?
Most delicate epithelium
* Where there is filtration (kidney); diffusion (lung);
secretion where slippery surface needed (e.g. outer layer
of serous membranes);
Where does mesothelium line?
Mesothelium is a layer of simple squamous cells that lines the serous
membranes (peritoneum (abdominal cavity + organs)),
pericardium (heart) , pleura (lungs) of the adult.
What is the difference between endothelium and mesothelium?
Endo lines inside the heart, blood vessels, lymphatic vessles and meso lines pericardial, pleural, peritoneal
cavities.
What do simple cuboidal epithelium look like?
Cuboidal or hexagonal boxes.
* The distance between adjacent nuclei is approx. the height of epithelium
What is the function of simple columnar epithelium and what does it look like?
- Reflects being more metabolically active than squamous
cells and it looks rectangular
What are other names for microvilli and where is it found?
Brush boarder and found on top of non-ciliated simple columnar epithelium. It increases surface area to absorb nutrients.
What does ciliated columnar epithelium do?
synchronous movement assists motility of mucus and foreign objects
or oocytes (help moves the egg BEFORE ovulation).
Is globet cell a modified columnar cell?
Yes
Where are the globet cells in ciliated simple columnar epithelium vs non-ciliated simple comunlar.
Globlet cells are interposed in non-ciliated simple columnar cells meaning scattered throughout the epithelium.
