signalling between tissues Flashcards
list the functions of cell signalling
Transfer signals voluntary muscles fight/flight - sympathetic nervous system spinal reflex - move hand etc Homeostasis
What is endocrine signalling
signal released by one cell and acts on another cell
example of endocrine signalling
glucagon released alpha cells act on liver - glycogenolysis and gluconeogenesis.
insulin: B cells - muscle
Adrenaline: adrenal gland - trachea
what is paracrine signalling
signal released by cell acts on adjacent cell
example of paracrine signalling
Insulin from B cell act on A cell
nitric oxide: endothelial - smooth muscle
osteoblast factors activate osteoclast
what is signalling via membrane attached proteins?
cells communicate via proteins attached to cell surface membrane
signals via membrane attached signals example
immunology
MHC bind TCR and activate it
HIV glycoprotein - CD4 receptor on glycoprotein
what is autocrine signalling
signal released by cell acts on same cell
what is an example of autocrine signalling
activated T cell release IL2 and has IL2 receptors
tumour cells mediate growth by own growth factors
neurotransmitter - same cell to inhibit production
acetylcholine - M2 muscarinic receptors
what are examples of intercellular signalling
between pancreas and liver - glucose
between A and B cells
What are examples of intracellular signalling
ionotropic receptors
enzyme linked receptors
G-protein coupled receptors
Intracellular receptors
explain the transmission of an extracellular signal within a cell
intracellular receptors - type 1 in cytosol, type 2 in nucleus, bind DNA, impact transcription/translation
G-protein coupled reaction - ligand bind to receptor, more available for binging of G protein heterotrimer, GTP replace GDP, dissociate, bind to target, GTPase, GTP-GDP, not active. Gs - adenylyl cyclase - ATP to cAMP - activate PKA - increase heartrate. Gi - reduce PKA and heartrate. Gq - PIP2 to IP3 and DAG - IP3 stimulate Ca2+ production - vasoconstriction.
enzyme linked receptor - ligand bind - activate receptor - phosphorylate receptor - signal bind. Tyrosine kinase. guanylyl cyclase. serine threonine kinase.
physiological examples of ionotropic
nictonic acetylcholine - muscle contraction
GABA-A - reduce neuron excitability
GPCR examples
beta 1 adrenergic receptor increase heartrate
M2 muscarinic receptor decrease heart rate
AT -1 angiotensin receptor - vasoconstriction
Enzyme linked receptors
insulin receptor - glucose uptake
ErbB receptor - cell proliferation
natriuretic peptides - vasodilation
