Epithelial Tissue Flashcards
What are 2 characteristics of all epithelial tissue?
1) Adhere to a basement membrane
2) Joined by junctional complexes (e.g. tight junctions, adhering juctions, desmosomes, gap juctions)
What type of junction binds epithelial cells to the basal lamina?
Hemidesmosomes
Do epithelial tissues have much ECM?
No
What are the components of the basal lamina?
1) Laminin
2) Type IV collagen (non-fibrillar)
3) Glycoproteins/proteoglycans
What secretes the basal lamina?
Hemidesmosomes and associated proteins
What collagen type makes the reticular lamina?
Collagen III (Fibrillar collagen)
What collagen links the basal lamina to the reticular lamina?
Collagen VII
What secretes the fibrillar collagens that make the reticular lamina?
Cells of the connective tissue
At the LM level, the basal lamina with the reticular lamina is referred to as?
Basement membrane
What germ or germ layers does epithelial tissue arise from?
ALL 3
1) ectoderm: epidermis, hair, nails, glands
2) mesoderm: Urogenital tract
3) Endoderm: lining of the GI tract and pharynx
What is the function of epithelial cells?
They line all surfaces and tubes of the body. Provides a barrier.
In H&E, the basement membrane is?
Eosinophilic
In the PAS, what color is the basement membrane?
Pink
What epithelial cells are flat/attenuated and have a flattened nucleus?
Squamous
Which epithelial cell is square in height, the height and width are equal, and the nucleus is central?
Cuboidal
Which epithelial cell has a nucleus that is found at the base and the height exceeds the width?
Columnar
What does simple epithelium imply?
A single sheet/cell layer
What does stratified epithelium imply?
2 or more layers of cells- Only the basal layer contacts the basal lamina
How do you classify a stratified epithelium?
By the shape of the cells at the cell surface
