Flashcards in Quiz 2 Vocabulary Deck (17)
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1
membrane potential
a separation of charge (in the form of different type of ions ) between the two sides of a cell membrane
2
depolarization
the reduction of a cell's membrane potential -- that is, a reduction is the overall separation of charge
3
ligand
generic name for a molecule that has the right shape to bind with a protein
4
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
5
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)
6
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
7
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
8
adenylate cyclase
an enzyme that catalyzes the conversion of ATP to cyclic AMP (cAMP)
9
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)
10
tropic hormone
a hormone that stimulates the release of another hormone
11
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)
12
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
13
interneurons
any neuron within ta nervous pathway positioned in between sensory and motor neurons
14
transmission
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
15
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.
16
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)
17
