Unit 2: Histology Flashcards
4 types of tissues
- Epithelial (covers/lines body, covers and lines organs)
- Connective( supports/pads)
- Nervous (controls brain/spine)
- Muscular (produces movement)
2 main types of Epithelial tissue:
Covering and Lining Epithelial
- outer layer of the skin
- lines open cavities of urogenital, respiratory tract, digestive tract.
- covers walls and organs of the closed ventral body cavity
- Glandular Epithelia
- secretory tissue in glands(eg sweat)
Epithelial cells have….
Polarity
Apical surface
Upper, free or exposed surface(different from “top” surface)
Exposed body surface or cavity of internal organ
Apical surfaces may bear microvilli or cilia
Basal surface
Lower, attached surface
Attached to a membrane that holds in place.
Non-cellular basal lamina of glycoproteins and collagen(glue) lies adjacent to basal surface.
Basement membrane is made of 2 Layers:
Basal lamina-adhesive sheet of glycoproteins and collagen fibers(glue)
Reticular lamina-layer of extracellular material and fine collagen fibers that weaves into the underlying connective tissue. thread/stitch*provides support and holds cells together
Closely packed cells
Tight junctions- plasma membranes of neighboring cells are bound together to form an IMPERMEABLE barrier.
Desmosomes- a thickened plasma membrane of neighboring cells are joined together by filaments(stitches)
Highly regenerative
Divided rapidly
Divided by mitosis at an increased rate to replaced dead or damaged cells or cells lost to friction, bacteria and chemicals.
Classification: Naming of Epithelia (Ask 2 questions…)
How many layers??
1: simple
2. Stratified
What TYPE of cell?
squamous
Cuboidal
Columnar
(Name by most apical layer of cells)
Simple squamous
“Fried egg”
D: Central nuclei not much plasma
F: diffusion & filtration where protection is not important. Secretes lubricating substances in serosae.
L: kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, lymphatic vessels, central body cavity lining.
Highly regenerative
Divided rapidly
Divided by mitosis at an increased rate to replaced dead or damaged cells or cells lost to friction, bacteria and chemicals.
Classification: Naming of Epithelia (Ask 2 questions…)
How many layers??
1: simple
2. Stratified
What TYPE of cell?
squamous
Cuboidal
Columnar
(Name by most apical layer of cells)
Simple squamous
“Fried egg”
D: Central nuclei not much plasma
F: diffusion & filtration where protection is not important. Secretes lubricating substances in serosae.
L: kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, lymphatic vessels, central body cavity lining.
