Epithelium Flashcards
What 3 distinct areas is the oral mucosa split into?
- Epithelium
- Connective Tissue or lamina propria
- Sub-mucosa
Epithelial Cell shape and structure photo:
How are epithelial cells classified number of layers?
How are epithelial cells classified depeing on shape of cell?
Epithelial cell classification
What can stratified squamous epithelium be divided into?
- Masticatory oral mucosa- (gingival and hard palate)- keratinising
- Lining oral mucosa- (floor of mouth, buccal regions and oesophagus)- non keratinising.
- Specialised (the dorsum of the tongue)- both.
What is the Function of oral mucosa epithelium?
- Protection of underlying tissue
- The different epithelium form lipid based permeability barriers.
- Protect from fluid loss
- Protect from ingress of potentially harmful environmental agents.
What is cell prolieration?
An increase in the number of cells; as a result of cell growth and cell division.
How does a cell divide?
A cell reproduces by performing an orderly sequence of events in which it duplicates its contents and then divides in two.
What is the definition of a ; Growth factor & Transcription factor?
Growth factor- polypeptides that control animal cell growth and differentiation. Usually produced near where they act. Can be stored and released by ECM.
Transcription factor- a protein that regulates the activity of RNA polymerase
What happens with proliferation of Stem cells?
- Not terminally differentiated
- Divide without limit
- When divides, each daughter cell has choice-
What does Differentiation mean?
The process by which cells or tissues undergo change toward a more specialised form or function.
How do cells stop dividing and differentiating?
Equilibrium cells removed from surface and replaced from behind.
Removal of intergrin expression.
What is the Cytoskeleton-definition?
- System of protein filaments in the cytoplasm of a eukaryotic cell that gives the cell shape and the capacity for directed movement.
- Most abundant components: actin filaments, microtubules and intermediate filaments.
What must cells have to be able to do?
- Organise themselves in space and interact mechanically with their environment.
- Be correctly shaped, physically robust and properly structured internally.
- Be able to change shape, move from place to place.
- Be able to rearrange internal components as they grow, divide, adapt to changes.
- Spatial and mechanical functions are developed to high degree in eukaryotic cells.
What are the functions of the Cytoskeleton?
Chromosome apart
Cytokinesis
Drives and guides intracellular traffic of organelles.
Support
Enables cells to move.
Machinery for muscle cell contraction and neuron extension.
Three families of protein molecules which assemble to form three main types of filaments.
What are Intermediate filaments?
- Ropelike fibres diameter around 10nm.
- Made of intermediate filament proteins.
- One group forms nuclear lamina.
- Others extend across the cytoplasm giving mechanical strength.
- In epithelial tissue, span the cytoplasm from one cell-cell junction to another, strengthening the entire epithelium.
What are the 4 phases in Eukaryotic cell cycle?
- G1
- S
- G2
- Mitosis
DNA replication occurs during the S phase
How does the cells in the Basal layer know to replicate and divide?
Signals are sent to Receptors via Extracellular matrix and new Progenitor cells are made by Phosphorylation.
What are the 2 types of Keratins?
Type I: smaller and acidic (K9-20) have molecular weight 40-64 kDa and encoded on chromosome 17q
Type II: larger and basic (K1-8) have molecular weight 52-67kDa and encoded on chromosome 12q
