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What are the four "tissue" types that cells are organized into?
epithelial, connective, muscle, nerve
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(Informational) What are some generalizations of epithelial cells?
Function as boundary (seperating compartments), cells are contiguous and form continous sheets, avascular (could compromise thier function)
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What characteristic is of epithelial cells that live in harsh environment?
Self-renewal. Because these cells need to divide and differentiate to compensate for these loses (think of listerine and lost of epi. cells)
Self renewal process = stem cell --> divides in 2 cells (one becomes epithelial cell and one remains stem cell)
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One layer of epithelail cells =? More than one layer of epithelial cells =?
- 1. Simple
- 2. Stratified (or pseudostratified)
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pseudostratified columnar
**usually ciliated and all cells rest on basement membrane
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Stratified squamous non-cornified
**cornified = no nucleus
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Stratified squamous cornified
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stratified squamous non-cornified
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Microvilli are made from what? What is there function?
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Stereocilia are based on what type of material? What are they?
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Cila are based on what type of material?
- **MV = microvilli, arrow is pointing to cilia
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Three types of cell-cell junctions?
- 1. tight or occluding junctions
- 2. anchoring junctions
- 3. communicating junctions
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what are occluding junctions functions and made up of?
- Function: near apical side but on lateral side and functions
- 1. to keep things from lumen from getting into epithelial cell
- 2. to prevent passage of molecules between cells
ocludin and claudin are transmembrane proteins that create tight jxn
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Two types of anchoring junctions? Differences similarities?
- 1. Adheren junction: actin-based, continuous belt, uses cadherin adhesion protein
- 2. Desomosome: intermediate filament-based (i.e. keratin), spot-weld plaque (achoring protein), has cadherin family protein between spot-weld plaques
- **On the EM: Dark bars are plaques (anchoring proteins), long horizontal lines are IF, space inb/w plauques are cadherin family adhesion protein
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Function of anchoring junctions? Things common to anchoring junctions?
1. transmit stress from cells
- 2.
- A) transmembrane protein (cadheren family)
- B) cytoskeletal filament (either actin or IF [i.e. keratin])
- C) intracellular anchor proteins
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What is a gap (communicating) junction made from? Function?
Made up of 6 connexins, combined laterally to make up connexons.
They let small molecules through.
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Order of cell-cell communication junctions?
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What is a hemidesmosome? What transmembrane adhesion protein and basal lamina protein does it use? Function?
- 1. Attaches the basal side of epithelial cell to basal lamina (ECM)
- 2. Uses integrin adhesion transmembrane protein (unlike cadheren in desmosomes) and laminin to connect to basal membrane and IF (like desmosomes)
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1 Connect lateral edges of cells
2 Connect basal side of cell to ECM
3 Connect to IF
4 Connect to Actin
5 Based of Connexins and Connexons
6 Use integrin/laminin
- 1. tight, anchoring (desmosomes, adheren jxn), gap
- 2. hemidesmosomes
- 3. desmosomes and hemidesmosomes
- 4. Adheren junction (not all anchoring junctions since desmosomes are part of it)
- 5. Gap (communicating) Junctions
- 6. Hemidesmosomes
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Claudin?
transmembrane protein of tight (occluding jxn)
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Occludin?
transmembrane protein of tight (occluding jxn)
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Cadherin?
transmembrane protein in anchroing jxns (desmos., and adherein jxn)
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Integrin?
transmembrane protein of hemidesmosomes
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Laminin?
protein of hemidesmosomes that connects to basal lamina
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Connexon?
Connexins that form to create gap junction to allow small molecules to pass through
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Endocrine vs. exocrine glands?
Endocrine: secrete into ductless blood stream
Exocrine: secrete from gland into duct until it hits circulation
- Picture of exocrine below
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Apocrine vs. holocrine vs. merocrine glands are each an example of what type of mode of cellular secreting product? Definition of each?
1. Exocrine glands
Apocrine: "Apex" of the cell comes off with material being secreted
Holocine: "whole" cell comes off duct with secretory product
Merocrine: "mirror" the secretory product is given off with no disruption of cell (exocytosis)
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Exocrine glands can be categorized into 2 groups? One groups is composed of two other groups?
- 1. Unicellular
- 2. Multicellular (simple, compound)
- simple: no branches, one duct
- compound: one main duct branches out into other ducts
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metaplasia?
A switch between one type of differentiated cell with another. Can bring a dividing cell one step closer to metastatic cancer
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