Intermediate Filaments (size)
an intermediate size between actin and microtubules
epithelial-derived intermediate filament
mesenchymally-derived intermediate filament
nerve-derived intermediate filament
recovery from last cell division, DNA synthesis
DNA condenses and centrioles and centromeres migrate to opposite poles. chromosomes begin to line up at midline.
the stage in mitosis or meiosis in which the duplicated chromosomes line up along the equatorial plate of the spindle
microtubules are broken down as the chromosomes pull apart from each other. each daughter cell has a full complement of DNA.
1. mitotic spindle starts to break down
2. purse string process: actin and myosin pull the 2 daughter cells apart
3. cytokinesis is the process of pulling apart cytoplasm in order to create 2 daughter cells
membranous tissue covering internal organs and other internal surfaces of the body
1. shape of nuclei (indicates number of layers)
2. polarity of cell
How to ID and characterize epithelium
Lamina propria functions
1. provide nutrition to epithelium
2. provide anchorage point for the epithelium
how do we view the lamina propria?
Lamina propria def
the connective tissue beneath the epithelium
how do we view the basal lamina?
basal lamina functions
1. supports the epithelium
2. barrier to foreign material from the connective tissue
3. proliferation (contain elements that signal when we need to replace epithelial cells)
4. establishes basal polarity
6. metabolism (nutrition comes from the CT)
Basal lamina + reticular lamina
what is the basement membrane comprised of?
series of fibers form the lamina propria that helps to anchor the epithelium to the connective tissue beneath it
lamina densa and lamina lucina
what makes up the basal lamina?
type IV collagen and a little bit of type VII
What are the two collagens that make up the basal lamina?
Laminin (a glycoprotein)
what establishes the function of the basal lamina
what is another name for a "tight junction"
describe a zonula occludens
1. most apical type of intracellular junction
2. completely encircles cell
3. tightly sealing
describe a zonula adherens
is typically just basal to tight junctions and helps maintain the seal. The attachment between the cells is mediated by transmembrane proteins called cadherins which are localized in the membranes between plaques.
another name for desmosome
name for half a desmosome, found at the basal aspect of the epithelium
describe a macula adherens
a spot junction consisting of two dense granular attachment plaques composed of several proteins on the cytoplasmic surfaces of opposing cell membranes