L3 Cell To Cell Communication Flashcards
What is defined as a mediator?
A chemical, peptide or protein that conveys information from one cell to another
What are the 3 experimental criteria that establish a substance as a mediator?
1) Released from cells in sufficient amounts to produce a biological action on target cells
2) Application of an authentic sample of the mediator reproduces the original biological effect
3) Interference with the synthesis, release of action
What are the 5 main types of intercellular communication?
Contact- dependent
Paracrine
Autocrine
Synaptic
Endocrine
What does intercellular mean?
Intercellular refers to anything that occurs between cells
How are the different types of intercellular communication different from one another?
Signals can act locally or over long distances
Signals can vary in speed and selectivity
What is contact- dependent signalling? Can you give any examples?
Type of cell signalling where cells need to be in direct physical contact ( Shortest range of all types of cellular communication)
Example: Immune response (T cell receptors interacting with receptors on antigen presenting cells), Development ( Delta- Notch signalling)
What is paracrine signalling and can you give any examples?
Signalling molecules/ mediators are released by a cell and travel to neighbouring cells. Mediators are stored in vesicles or synthesised on demand
Examples:
Histamine - contributes to allergic response
Nitric oxide - influences blood vessel diameter
Eicosanoids (prostaglandins) - involved in inflammation
What is autocrine signalling?
Cell produces and releases signalling molecules that act on receptors of its own surface rather than the surface of neighbouring cells.
What is neuronal signalling? Can you give any examples of the chemical mediators that they use?
Signalling through neurones across synapses with other cells such as muscle or glandular (specific target cells)
Chemical mediators are neurotransmitters
Examples: Acetylcholine - released at the neuromuscular junction and onto the heart
Noradrenaline - released onto the heart
What is endocrine signalling?
Endocrine signalling involves releasing signalling molecules, hormones, into the bloodstream and travel to distant target cells
Give me examples of what some hormones can be
A protein e.g. insulin
Amino acid derived e.g. adrenaline (epinephrine)
A steriod e.g. estradiol
What are the typical chemical mediators for the 5 types of intercellular communication?
Contact- dependent - Anything
Paracrine - Mediators stored in vesicles
Autocrine - Mediators stores in vesicles
Synaptic (Neuronal) - Neurotransmitters
Endocrine -Hormones
Which intercellular communication is the slowest and the fastest with their speed of communication?
Synaptic (neuronal) - fastest
Endocrine signalling - Slowest
Is endocrine signalling specific?
It is not specific
Synthesis of chemical mediators occurs in two ways. What are they?
1) Synthesis of small molecular mediators is regulated by specific enzymes (which mediator produced depends on which enzymes are active)
2) Synthesis of peptides is regulated by transcription
(which mediator produced depends on which genes are active)
