1. Modes of cell communication Flashcards
What are the different modes of cell communication?
Autocrine, Paracrine, Juxtacrine, Endocrine
Describe Autocrine Regulation
Where signalling molecules bind to target receptors on the same cell (on the cell secreting these signalling molecules).
Describe Somatiostatin production in the stomach and this occurs by what mode of communication.
Autocrine. Somatostatin is produced by D cells in the gastric glands and binds to SST2R receptors on d cells, inhibiting adenylyl cyclase, decreasing cAMP and causing a negative feedback loop, decreasing somatostatin production. It also binds to SST2R receptors on parietal cells which decrease gastric acid production.
Describe Paracrine Regulation
Where signalling molecules bind to target receptors on adjacent cells without passing through the circulatory system.
How is Histamine produced in stomach-pancrine regulation?
it is produced by entero-chromaffin like cells In the gastric glands in response to stimulation by acetylcholine.
Describe the action of Histamine in the stomach-pancrine regulation
Histamine binds to H2 receptors which activate adenylyl cyclase. cAMP increases, increasing number of proton pumps, increasing gastric acid secretion from parietal cells. This aids digestion.
Describe Endocrine Regulation
Where signalling molecules bind to cells by entering the circulatory system. This is used for long distance communication.
Give an example of Endocrine Regulation
Hypophyseal portal system - ACTH hormone is secreted from cells in the pituitary gland into the connected circulatory vasculature.
What is Juxtacrine Regulation?
An extracellular matrix signalling which requires the close contact of cells.
What is Synaptic transmission?
Communication between neutrons which generate an action potential (electrical impulse) to pass on info.
What are dendrites and axons?
Dendrites - receive incoming info and send to axons
Axons - Send info to the cell.
What is the synaptic cleft?
The space between the pre-synaptic and post-synaptic neuron.
Describe synaptic transmission
Pre-synaptic neuron releases neurotransmitters in vesicles into the synaptic cleft when excited by a singal. They bind to receptors on the post-synaptic neuron, generating an action. There is then a re-uptake or diffusion of the neurotransmitters.
What is the Pre-synaptic and Post-synaptic neutrons?
Pre-synaptic - where signal is initiated
Post-synaptic - where info is received
What is ‘Exocytosis’ ?
The transport of materials from inside the cell into the extracellular fluid
