Ch. 14 Flashcards
Define neuron.
A nerve cell; the fundamental signaling unit of the nervous system, composed of a cell body and elongated processes (dendrites and axon) that carry electrical signals
Define presynaptic.
Transmission of a signal to a postsynaptic cell at a synapse
Define postsynaptic.
Reception of a signal from a presynaptic cell at a synapse
Define axon.
Elongated process of a neuron specialized for conveying action potentials away from the cell body
Define dendrites.
The receptive element of most neurons, which receives synaptic input from other neurons
Define axon terminals.
The part of a neuron that makes synaptic connections with another nerve cell or with an effector cell
Define voltage.
A measure of the potential energy present because of charge separation (electric potential)
Define current.
The flow of electric charge
Define resting membrane potential.
The normal electrical potential across the cell membrane of a cell at rest
Define action potential.
A brief electrical signal of about 100 mV across the cell membrane of a neuron or other excitable cell
Define passive current.
Current conducted by neurons without action potentials
Define depolarization.
Any increase in the inside positivity of a cell membrane
Define hyperpolarization.
Any increase in the inside negativity of a cell membrane
Define sensitivity.
The ability of a sensory cell to distinguish stimuli of different intensity
Define specificity.
The ability to distinguish among different stimulus types
Define stimulus.
A change in the external environment or in internal conditions that an animal can detect and respond to
Define ionotrophic.
A kind of sensory transduction in which a sensory receptor molecule is itself an ion channel, changing ion flow into the cell in direct response to a sensory stimulus
Define metabotrophic.
A kind of sensory transduction in which a sensory receptor molecule is a G protein that activates a second messenger, eventually producing a receptor potential.
Define mechanoreceptor.
A sensory receptor cell specialized to respond to mechanical stimulation
Define adaptation.
A decrease in the frequency of action potentials in response to a stimulus
Define proprioceptors.
A sensory receptor that provides an animal with information about the relative position or movement of parts of its body
Define hair cell.
A sensory epithelial cell in a vertebrate acoustico-lateralis system that transduces displacement of its apical stereocilia into an electrical signal
Define vestibular system.
System that functions to detect the position and movement of our head in space, allowing for the coordination of eye movements, posture, and equilibrium
Define hearing system.
System that functions to process how we hear and understand sounds within the environment
Define cochlear amplification.
An increase in the movement of the basilar membrane in the cochlea in response to sound
Define GPCR.
G protein-coupled receptor; a membrane receptor protein that, when it binds to its specific extracellular signal ligand, relays a signal into the cell by activating G proteins in the cell membrane
Define photoreceptor.
Sensory cell that responds to light stimulation through a photopigment that absorbs light and triggers a response
Define phototransduction.
Generation of an electrical response in a photoreceptor cell in response to a light stimulus
Define dark current.
The ionic current, carried mainly by Na+ ions, that flows into the outer segments of vertebrate photoreceptors in the dark
What is the predominant form of neurotransmission?
Action potential
