CELL SIGNALLING Flashcards
What 5 processes does cell signalling allow for?
Movement
Metabolism
Growth
Development
Immune response
What are gap junctions?
Gaps between cytoplasm. Which allows molecules to be passed across without being excreted into extracellular fluid
What are the advantages of gap junctions
Allows movement of ions
Allow the movement of metabolites & intracellular signaling molecules such as cyclic AMP (cAMP)
Essential in embryonic development
What are some disadvantages of gap junctions ?
Can only communicate with adjacent cells
Relatively slow transmission across an organ.
Potential transmission of deleterious factors from one cell to another.
What are some disadvantages of neuronal communication?
Specificity
Hardwiring is expensive - metabolic maintenance of the neural system.
Possibly vulnerable - damaged neurons take a long time to be replaced.
What are lipid rafts
More tightly packed lipid molecules with higher concentration of receptors and cell signalling molecules
What are cytokines
Soluble proteins or glycoproteins produced by cells.
They are important signalling molecules, especially in the context of inflammation and innate immunity.
What do cytokines do?
They mediate and regulate immunity (innate and adaptive), haematopoesis and embryogenesis.
They are signals setting out the local cellular environment.
Brief and self limiting if the stimulus is removed.
What is pleiotrophy?
The same cytokine can bind to multiple cells and each cell will have a different reaction and produce a different outcome
What is redundancy?
2 or more cytokines have the same or similar effects on the cell
What is synergy?
The combined effect of cytokines can be greater/additive compared to the action of each cytokine alone.
What is antagonism?
One cytokine may inhibit the activity of another.
What is cascade activation?
One cytokine may induce a cascade of cytokine expression involving multiple cells
What type of cell signalling allows ion movement across gap junctions.
Paracrine
Cell contact dependent
How do immune cells know where to move?
Move towards higher concentration of cytokines
