Session 6 Flashcards
What are three ways in which cells can communicate?
Paracrine
Endocrine
Synaptic
What is paracrine communication?
Adjacent cells are effected within a tissue by local chemical mediators
What is endocrine communication?
Message released into bloodstream and affects a distant cell
What is synaptic communication?
Neurotransmitter crosses a synaptic cleft and binds to receptors on the post synaptic membrane of the target cell
What kind of molecule do cell surface receptors bind?
Hydrophillic, such as insulin and glucagon
What kind of molecule do intracellular receptors bind?
Small hydrophobic signalling molecules (bound to a carrier in blood) bind to intracellular recptors in nucleus or cytoplasm. (Thyroid and steroid hormones)
What is a ligand?
Any small molecule that binds to a receptor site.
What is a ligand called if it produces a response in a receptor?
An agonist
What is an antagonist?
A ligand which binds to a receptor without causing any activation.
What is an agonist which stimulates a receptor but are unable to elicit the maximum cell response called?
Partial agonists
What is the definition of a receptor?
A molecule which specifically recognises a ligand or family of ligands and which, in response to ligand binding brings about regulation of a cellular process. In the unbound state, a receptor is functionally silent.
What are the 8 roles of receptors?
- Signalling by hormones/ local chemical mediators
- Neurotransmission
- Cellular delivery
- Control of gene expression
- Cell adhesion
- Modulation of the immune response
- Sorting of intracellular proteins
- Release of intracellular calcium stores
What is an acceptor?
A molecule whos basic function can be carried out without the interaction of a ligand.
What are the two types of acetylcholine receptors?
Nicotinic and muscarinic
What are the three muscarinic receptors, and their antagonists?
M1 Pirenzipine
M2 Gallamine
M3 Hexahydrosiladiphenol