Chapter 4 B&B Grade A Q&A
electrical stimulation - (correct answer)passage of an electrical current from the
uninsulated tip of an electrode through tissue, resulting in changes in the electrical
activity of the tissue.
voltmeter - (correct answer)device that measure the flow and the strength of electrical
voltage by recording the difference in electrical potential between two bodies
electroencephalogram (EEG) - (correct answer)graph that records electrical activity
through the skull or from the brain and represents graded potentials of many neurons
oscilloscope - (correct answer)Device that serves as a sensitive voltmeter by registering
the flow of electrons to measure voltage.
the scales used when recording the electrical charge from a nerve are millivolts (1/1000
of a volt) and milliseconds (1/1000 of a second)
In this device, an electron beam leaves a trace on a screen. Deflections of the beam
can be used to record voltage changes on an axon
microelectrode - (correct answer)a microscopic insulated wire or a salt-water-filled flass
tube of which the uninsulated tip is used to stimulate or record from neurons.
can deliver an electrical current to a single neuron or record from it
two types of microelectrodes
a) wire 1 micrometer in size, placed into or on the axon
b) glass tube filled with salt water and a wire inside the tube, which can be used to
measure extracellular current, intracellular current and membrane current.
,diffusion - (correct answer)movement of ions from an area of higher concentration to an
area of lower concentration through random motion
requires no work, results from the random motion of molecules as they move and
bounce off one another to gradually disperse in a solution. when diffusion is complete, a
dynamic equilibrium, with an equal number of molecules everywhere, is created
concentration gradient - (correct answer)differences in concentration of a substance
among regions of a container that allow the substance to diffuse from an area of higher
concentration to an area of lower concentration
describes the relative concentration of a substance in space or in a solution. (EX: ink
dropped into water diffuses from the initial point of contact...until it is equally distributed
throughout the water)
area of higher concentration to an area of lower concentration
voltage gradient - (correct answer)difference in charge between two regions that allows
a flow of current if the two regions are connected
the difference in charge between two regions. Ions will move down a voltage gradient
from an area of higher charge to an area of lower charge
resting potential - (correct answer)electrical change across the cell membrane in the
absence of stimulation; a store of potential energy produced by a greater negative
charge on the intracellular side relative to the extracellular side
can vary from -40 to -90 millivolts on axons of different animal species. The exact
potential on an axon does not influence the neuron's ability to participate in generating
brain activity. Four charged particles take part in producing the resting potential: ions of
sodium, potassium, chloride, and proteins.
, more protein cations and potassium (K+) cation in the intracelluar fluid, and more Cl-
and Na+ ions in the extracellular fluid.
experimental results obtained over hundreds of years from electrical ___________ and,
more recently, from electrical ___________ implicated electrical activity in the nervous
system's flow of information - (correct answer)stimulation; recording
by the mid-twentieth century, scientists solved three technical problems in measuring
the changes in electrical charge that travel like a wave along an axon's membrane:
___________,___________,and ___________. - (correct answer)recording from the
giant axons of the North Atlantic squid; using an oscilloscope to measure small changes
in voltage; crafting microelectrodes small enough to place on or into an axon
the electrical activity of neuronal axons entails the diffusion of ions. ions may move
down a ___________ and down a ___________. - (correct answer)concentration
gradient, from an area of relatively high concentration to an area of lower concentration
voltage gradient, from an area of relatively high charge to an area of lower charge
in what three ways does the semipermeable cell membrane affect the movement of ions
in the nervous system? - (correct answer)ion channels in cell membranes may open to
facilitate ion movement, close to impede ion movement, or pump ions across the
membrane
graded potential - (correct answer)small voltage fluctuation in the cell membrane
restricted to the vicinity on the axon where ion concentrations change to cause a brief
increase (hyperpolarization) or decrease (depolarization) in electrical charge across the
cell membrane
graded potentials dont go very far but an isolated axon must somehow be stimulated.
Stimulating an axon electrically through a microelectrode mimics the way in which
membrane voltage changes to produce a graded potential in the living cell. If the voltage
applied to the inside of membrane is negative, the membrane potential increases -
electrical stimulation - (correct answer)passage of an electrical current from the
uninsulated tip of an electrode through tissue, resulting in changes in the electrical
activity of the tissue.
voltmeter - (correct answer)device that measure the flow and the strength of electrical
voltage by recording the difference in electrical potential between two bodies
electroencephalogram (EEG) - (correct answer)graph that records electrical activity
through the skull or from the brain and represents graded potentials of many neurons
oscilloscope - (correct answer)Device that serves as a sensitive voltmeter by registering
the flow of electrons to measure voltage.
the scales used when recording the electrical charge from a nerve are millivolts (1/1000
of a volt) and milliseconds (1/1000 of a second)
In this device, an electron beam leaves a trace on a screen. Deflections of the beam
can be used to record voltage changes on an axon
microelectrode - (correct answer)a microscopic insulated wire or a salt-water-filled flass
tube of which the uninsulated tip is used to stimulate or record from neurons.
can deliver an electrical current to a single neuron or record from it
two types of microelectrodes
a) wire 1 micrometer in size, placed into or on the axon
b) glass tube filled with salt water and a wire inside the tube, which can be used to
measure extracellular current, intracellular current and membrane current.
,diffusion - (correct answer)movement of ions from an area of higher concentration to an
area of lower concentration through random motion
requires no work, results from the random motion of molecules as they move and
bounce off one another to gradually disperse in a solution. when diffusion is complete, a
dynamic equilibrium, with an equal number of molecules everywhere, is created
concentration gradient - (correct answer)differences in concentration of a substance
among regions of a container that allow the substance to diffuse from an area of higher
concentration to an area of lower concentration
describes the relative concentration of a substance in space or in a solution. (EX: ink
dropped into water diffuses from the initial point of contact...until it is equally distributed
throughout the water)
area of higher concentration to an area of lower concentration
voltage gradient - (correct answer)difference in charge between two regions that allows
a flow of current if the two regions are connected
the difference in charge between two regions. Ions will move down a voltage gradient
from an area of higher charge to an area of lower charge
resting potential - (correct answer)electrical change across the cell membrane in the
absence of stimulation; a store of potential energy produced by a greater negative
charge on the intracellular side relative to the extracellular side
can vary from -40 to -90 millivolts on axons of different animal species. The exact
potential on an axon does not influence the neuron's ability to participate in generating
brain activity. Four charged particles take part in producing the resting potential: ions of
sodium, potassium, chloride, and proteins.
, more protein cations and potassium (K+) cation in the intracelluar fluid, and more Cl-
and Na+ ions in the extracellular fluid.
experimental results obtained over hundreds of years from electrical ___________ and,
more recently, from electrical ___________ implicated electrical activity in the nervous
system's flow of information - (correct answer)stimulation; recording
by the mid-twentieth century, scientists solved three technical problems in measuring
the changes in electrical charge that travel like a wave along an axon's membrane:
___________,___________,and ___________. - (correct answer)recording from the
giant axons of the North Atlantic squid; using an oscilloscope to measure small changes
in voltage; crafting microelectrodes small enough to place on or into an axon
the electrical activity of neuronal axons entails the diffusion of ions. ions may move
down a ___________ and down a ___________. - (correct answer)concentration
gradient, from an area of relatively high concentration to an area of lower concentration
voltage gradient, from an area of relatively high charge to an area of lower charge
in what three ways does the semipermeable cell membrane affect the movement of ions
in the nervous system? - (correct answer)ion channels in cell membranes may open to
facilitate ion movement, close to impede ion movement, or pump ions across the
membrane
graded potential - (correct answer)small voltage fluctuation in the cell membrane
restricted to the vicinity on the axon where ion concentrations change to cause a brief
increase (hyperpolarization) or decrease (depolarization) in electrical charge across the
cell membrane
graded potentials dont go very far but an isolated axon must somehow be stimulated.
Stimulating an axon electrically through a microelectrode mimics the way in which
membrane voltage changes to produce a graded potential in the living cell. If the voltage
applied to the inside of membrane is negative, the membrane potential increases -
