Cells And Tissues Flashcards
What ways are cells held together?
Lateral/Apical/Basal Domain
What are the different lateral domain attachments?
Tight Junction/Gap Junction/Desmosomes
How do tight junctions work?
Tight Junctions work by sealing off the inter membrane space in a non continual seal by inter membrane proteins.
How do gap junctions work?
Gap junctions have connexons (small disk shaped tunnels) that link the two cells together and they allow transport of ions and small molecules.
What are they types of feedback loops and what are the three basic components of a feedback loop.
Negative and Positive feeback.
- Receptor
- Control Centre
- Effector
How do desmosomes work?
The intracellular side of the plasmalemma has a desmosome attachment plaque which is anchored to intermediate filaments, as well as to transmembrane proteins between the two cells.
What are the basal attachment types?
Hemidesmosomes and Focal adhesion
How do Hemidesmosomes work?
They have an integrin (type of transmembrane protein) attached to the plaque. The integrin is also attached to a basement membrane in the extracellular matrix. Found in tissues subject to abrasion.
How does Focal Adhesion work?
Allows intracellular actin to attach to the basement membrane and the extracellular matrix. The integrin glycoproteins attach to the actin through actin binding proteins.
What are the types of apical domain?
Cilia; Microvilli; Stereovilli
How do Cilia work?
Motile cytoplasmic processes that carry out the EFFECTIVE STROKE and RECOVERY STROKE. Composed of microtubules.
What are stereovilli?
Long immotile microvilli that carry out absorption or sensory responsibilities in the epididymis and the middle ear.
What are microvilli?
Finger like projections extending from the apical surface of epithelial cells held in place by actin filaments
How do cells communicate?
- Direct contact commmunication: Through connexons in Gap junctions
- Autocrine: Releases extracellular signal that attaches to itself
- Paracrine: Secretes molecules to nearby target molecules
- Endocrine: Secreting cell releases molecule into blood supply (not ducts). Blood carries signal to target cell.
- Synaptic: Electrical signal causes release of neurotransmitter which diffuses across a synapse to target cell.
- Neurocrine: A nerve cell releases an electrical signal into the blood which takes it to the target cell.
What are cultured cells and what are their characteristics?
Cells taken out of organism and grown in favourable conditions. They exhibit contact inhibition and senescence. They are great research tools though.
