Kapitel 12 Flashcards
Traveling wave of electrical excitation caused by rapid - transient - self-propagating depolarization of the plasma membrane in a neuron or other excitable cell; also called a nerve impulse.
action potential
The movement of a solute across a membrane against its electrochemical gradient; requires an input of energy - such as that provided by ATP hydrolysis.
active transport
Long - thin extension that conducts electrical signals away from a nerve cell body toward remote target cells.
axon
An active transporter that uses energy supplied by ATP hydrolysis to actively expel Ca2+ from the cell cytosol.
Ca2+ pump
A protein that forms a hydrophilic pore across a membrane - through which selected small molecules or ions can passively diffuse.
channel
Active transporter that uses the movement of one solute down its electrochemical gradient to drive the uphill transport of another solute across the same membrane.
coupled pump
Short - branching structure that extends from the surface of a nerve cell and receives signals from other neurons.
dendrite
A shift in the membrane potential - making it less negative.
depolarization
Driving force that determines which way an ion will move across a membrane; consists of the combined influence of the ion’s concentration gradient and the membrane potential.
electrochemical gradient
Transmembrane protein that forms a pore across the lipid bilayer through which specific inorganic ions can diffuse down their electrochemical gradients.
ion channel
Ion channel permeable to K + that randomly flickers between an open and closed state; largely responsible for the resting membrane potential in animal cells.
K + leak channel
An ion channel that is stimulated to open by the binding of a small molecule such as a neurotransmitter.
ligand-gated channel
An ion channel that allows the passage of select ions across a membrane in response to a physical perturbation.
mechanically gated channel
Voltage difference across a membrane due to a slight excess of positive ions on one side and of negative ions on the other.
membrane potential
Any transmembrane protein that provides a passageway for the movement of select substances across a cell membrane.
membrane transport protein