Lecture 6 Module 2 Flashcards
How is epithelia classified
Through shape, layers and surface specialisations (cilia or microvilli)
What are the 4 key types of tissue
Epithelial, connective/supportive, muscle and nervous
What do cells rest in and what is its purpose
Extracellular matrix which excreted from the cells, its function is support, structure and regulation of cell communication and behaviour
What are 2 examples of why ECM is important
Maintain differential states of cells and just for regular development
how does the basement membrane relate to a cell
The basal layer of a cell is connected to the basement membrane which is used as scaffolding and anchorage to the underlying connective tissues
Is epithelium vascular or avascular, and is it fast or slow at regeneration
Avascular(receives nutrients through diffusion instead) and very fast at regeneration
What are the cell shapes of epithelium
squamous, cuboidal and columnar
what are the cell layers of epithelium
simple, stratified, pseudostratified(only respiratory) and transitional(eg bladder)
Whats the difference between surface and glandular epithelium
Surface is covering, like for the internal organs. Glandular are secretory cells that can be grouped together into glands
what are the 3 functions/units of cellular junction
Occluding/holding together, anchoring and communicating
What are the types of individual junctions
Tight junctions/zonula occludens, zonula adherens, desmosomes, hemidesmosomes and gap junctions
Where is each of the individual junctions located
Tight junctions, at the upper apical region.
Zonula adherens at the apical region, working with the tight junctions
gap junctions, along the sides of the cells
desmosomes, along the sides of the cell
hemidesmosomes at the basal region of the cell
What are the roles of all the individual junctions
Tight junctions hold the cells together at the apical membrane and control the paracellular pathway.
Zonula adherens, strengthens the tight junctions connection/works with them. Links the cytoskeletons actin microfilaments sections together
Gap junctions, allows for communication between 2 cells
Desmosomes, anchors cells together along the length using the intermediate filaments/cytokeratin portion of the cytoskeleton
Hemidesmosomes, anchors the cell to the basement membrane for support and stability, also binds to the cytokeratin
What are the main proteins for each of the individual junctions
Tight junctions- occludin and claudins(controls permeability of tissues)
Zonula adherens-
E-cadherins(linked to metastasis)
Gap junctions- connexin proteins that make up connexon channels
Desmosomes- Cadherins, with examples of desmoglein
Hemidesmosomes- Integrins that connect to the cytoskeleton from the cell
Describe microvilli
0.5 - 1micrometres tall projections of the plasma membrane with a core of parallel actin bundles
Describe cilia
up to 10micrometre long projections. Has a cytoskeleton made of microtubules and can be motile or sensory
Describe the basement membranes purpose and arrangement
To bind epithelial cells to the underlying connective tissue. Regulates growth and differentiation to prevent cancer, forms a barrier between the cells and the CT that regulates its permeability to allow for nutrient passage. Made of a sheet like arrangement of ECM cells
What are the 3 layers of the basement membrane
From the closest to the basal cells surface to CT layer the order goes
The lamina lucida, lamina densa(basal lamina) and the lamina fibroreticularis
