4: Hormones and Receptors Flashcards
Juxtacrine signaling
cell to cell signaling
Endocrine signaling
hormone travels from one cell to another via the bloodstream
Paracrine signaling
hormone travels from one cell to another via a local mediator
Synaptic signaling
neurotransmitter reaches a target cell via a synapse
What do pancreatic alpha cells synthesize?
glucagon (polypeptide)
What do pancreatic beta cells synthesize?
insulin (polypeptide)
What does the adrenal cortex synthesize?
cortisol (steroid)
What does the adrenal medulla synthesize?
epinephrine (catecholamine)
What does the thyroid gland synthesize?
thyroxine
Where does hormone destruction typically occur?
liver
T/F: All the receptors on a target cell must be bound by a hormone to achieve a maximum signaling response?
F
What hormones use an intracellular recpetor?
cortisol, steroids, and thyroid hormones
Do hydrophobic or hydrophilic hormones cross the plasma membrane easier?
hydrophobic
What hormones use a cell surface receptor?
glucagon and epinephrine
4 types of cell surface recpetors?
- ligand-gated ion channels
- enzyme-linked
- cytokine
- g-protein coupled
Ligand-gated ion channel receptors
neurotransmitter binds to ligand which opens the channel to allow ions to pass
Enzyme-linked receptors
enzyme binds to the 2 subunits of the inactive catalytic domain, causing an intracellular conformation change
cytokine receptors
cytokine binds to a receptor, directly activating an intracellular enzyme
G-protein coupled receptors
neurotransmitter or hormone binds to receptor, causing a conformation change inside, which allows a G protein to bind intracellularly to the receptor, activating it; the activated G protein can then leave to activate an enzyme
What is the activated form of the GPCR bound to?
GTP
What is the inactivated form of GPCR bound to?
GDP
What is cyclic AMP derived from?
ATP
