Quiz 2 Vocabulary Flashcards Preview

Physiology 2420 > Quiz 2 Vocabulary > Flashcards

Flashcards in Quiz 2 Vocabulary Deck (17)
Loading flashcards...

membrane potential

a separation of charge (in the form of different type of ions ) between the two sides of a cell membrane



the reduction of a cell's membrane potential -- that is, a reduction is the overall separation of charge



generic name for a molecule that has the right shape to bind with a protein


ligand-gated ion channel

(ion channel-linked receptor, chemically activated ion channel) -- a membrane bound channel protein that opens via the binding of a specific type of molecule (a ligand) to some part of the channel


enzyme-linked receptor

a membrane bound receptor that upon binding to its ligand (on the outside of the cell) activates an enzyme on the cytosolic or inside of the cell that is part of the same membrane-spanning complex (as the receptor)


G-protein linked receptor

a membrane bound receptor that upon binding to its ligand (on the outside of the cell) activates a G-protein on the cytosolic or inside of the cell


second messenger

an intracellular chemical whose formation is triggered by the binding of a ligand to a membrane-bond receptor, and once formed triggers changes (often a whole series of changes) within the workings of the cell


adenylate cyclase

an enzyme that catalyzes the conversion of ATP to cyclic AMP (cAMP)


phospholipase C

an enzyme that catalyzes the splitting of a specific type of phospholipid into IP3 and DAG (both of which act as second messenger molecules)


tropic hormone

a hormone that stimulates the release of another hormone


voltage-gated ion channel

voltage-gated ion channel
an ion channel in which the opening and closing of its "gate" is controlled by changes in the membrane potential-- the charge gradient across the membrane. (typically, such channels open when the membrane is depolarized past some threshold, and closes when the membrane is re- or hyper polarized beyond that threshold)


axon hillock

the region along a nerve cell where voltage-gated ion channels are first located and thus an action potential can begin. (It is also called the trigger zone; and its location designates where the sensory end of a neuron stops, and the signal conduction region begins



any neuron within ta nervous pathway positioned in between sensory and motor neurons



when the firing of a presynaptic neuron has some means to directly influence whether the postsynaptic cell (be it neuron or muscle fiber) fires an action potential


chemical (direct) transmission

when a presynaptic neuron influences whether a post-synaptic neuron will fire an action potential by releasing a chemical signal (a neurotransmitter) that binds to and opens an ion channel. The effect could either be positive (stimulatory) or negative (inhibitory), based on the type of ion channel opened.


nicotinic A CH receptor

the ligand-gated ion channel, where acetylcholine is the ligand, found on postsynaptic muscle fibers at the neuromuscular junction (as well as some other locations). (the name comes from the fact that nicotine will also bind to and open these ions channels)



the enzyme (found on the postsynaptic cell in a neuromuscular junction) that catalyzes the breakdown of acetylcholine into acetate and choline, and thus plays a role in removing acetylcholine from the synapse