Cell Signalling Flashcards
Why do cells need to communicate
Process information
Self preservation
Voluntary movement
Homeostasis
Endocrine signalling
Hormone travels within blood vessels to act on a distant target cell
Paracrine signalling
Hormone acts on an adjacent cell
Endocrine signalling examples
Glucagon secreted by alpha cells of islets of langerhans in pancreas stimulates gluconeogenesis and glycogenolysis
Insulin secreted by beta cells of islets of langerhans acts on liver, muscle cells & adipose tissue
Adrenaline - adrenal glands acting on trachea
Paracrine signalling examples
Nitric Oxide produced by endothelial cells in blood vessels
Osteoclast activations factors produced by adjacent osteoblasts
Signalling between membrane attached proteins outline (I.e.Hep C)
Blood borne virus detected within blood stream by antigen presenting cell (APC)
APC digests pathogen expresses major histo-compatibility (MHC) molecules on surface
T cells engage with MHC molecule with TCRs
Membrane attached protein signalling
Plasma membrane proteins on adjacent cells interacting
Autocrine signalling definition
Signalling molecules act one the same cell
Ionotropic receptor
Ligand binding opens ion permeable pore traversing the membrane
Ion channel signal transduction events
Ligand binds to receptor protein
Change in conformation of a channel protein allows opening of a pore
Pore allows ions to move in or out of cell according to conc. grad.
Ionotropic receptor examples - Nicotine Acetylcholine
Ligand: Acetylcholine (ACh)
Location: Skeletal muscle
Physiological effect: Muscle contraction
G protein coupled receptor
Ligand binding activates intracellular G protein
G protein coupled receptor signal transduction events
