Cell To Cell Communicaion Flashcards
What is defined as a mediator?
A chemical or peptide that conveys information from cell to cell
When are mediators released?
Mediators are released in response to a stimulus and produce a particular response
What is the general principle of cell to cell communication?
1-Chemical mediators are released in response to a stimulus.
2-The mediators bind to a specific receptor on the target cells.
3-This initiates intracellular signals that alter cell behaviour
What is signal transduction?
Converting extracellular signal into intracellular signal
What are the 5 types of intracellular communication?
Contact dependent signalling
Paracrine signalling
Neuronal signalling
Endocrine signalling
Autocrine signalling
what is contact dependent signalling?
2 cells are in direct contact and act locally on neighbouring cells
The have a short range of communication
What is paracrine signalling?
When extracellular signals (mediators) act locally
These chemical mediators are stored in vesicles or made on demand
Why are steroid hormones not stored in vesicles?
Because they diffuse easily across a membrane
What is neuronal signalling?
Uses specialised structures like synapses
The signalling is restricted to specific target cells
The synapses can be long or short distances from neuronal cell bodies
Signalling is fast
Chemical mediators are known as neurotransmitters
Describe endocrine signalling
Mediators such as hormones are secreted into bloodstream
Signalling is slow and not specific
Long distances
What are the 2 ways chemical mediators can be made?
Specific enzymes
Transcription
Why does the storage and release of mediators vary?
Some mediators are pre-formed so they are stored in vesicles and released by exocytosis (eg insulin)
Whereas some mediators are produced on demand as they diffuse across membranes. These are released by diffusion (eg nitric acid). This takes longer to act than those stored in vesicles
what is the master regulator of chemical secretion?
calcium
