Chapter 1 Flashcards
david chalmers
easy and hard problem of consciousness
where does perception occur
in the brain
mental activity and brain activity are inseparable (t/f)
true
monism
belief that universe consists of only one kind of substance or being
dualism
belief that mind and brain are different substances and exist independently
who advocated for dualism
rene descartes
neural diversity
everyone varies in receptors in the brain and how they respond to stimuli
physiological explanation of behavior
relates behavior to activity of brain and other organs
physiological behavior example
male birds can sing because the brain area that allows singing is larger in males than females
ontogenetic explanation of behavior
how a structure or behavior develops due to influence of genes, nutrition, experiences, and interactions
ontogenetic behavior example
young male birds learn to sing from other male birds
evolutionary explanation of behavior
characteristic features are modifications of something found in ancestral species
evolutionary behavior example
similar species of birds have similar songs, evolved from single ancestor
functional explanation of behavior
describes why a behavior or structure evolved
functional behavior example
only the male bird sings to attract mates and ward off males
absolute refractory period
a time when the membrane is unable to produce an action potential
action potential
all-or-none message sent by axon
all-or-none law
amplitude and velocity of an action potential are independent of the stimulus that initiated it
concentration gradient
difference in distribution of ions across the neuron’s membrane
depolarize
to reduce polarization toward zero across a membrane
electrical gradient
difference in electrical charges between the inside and outside of the cell
graded potentials
a membrane potential that varies in magnitude in proportion to the intensity of the stimulus
hyperpolarization
increased polarization across a membrane (more negative, farther from zero)
in a myelinated axon, how would the action potential be affected if the nodes were much closer together? how might it be affected if the nodes were much farther apart?
if the nodes were closer, the action potential would travel more slowly. if they were much farther apart, the current might not be able to stimulate the next node enough to reach its threshold.
during the rise of the action potential, do sodium ions move into the cell or out of it? why?
during the action potential, sodium ions move into the cell. the voltage-dependent sodium gates have opened, letting sodium move freely. sodium is attracted to the inside of the cell by both an electrical and a concentration gradient.
as the membrane reaches the peak of the action potential, what brings the membrane down to the original resting potential?
after the peak of the action potential, potassium ions exit the cell, driving the membrane back to the resting potential. the sodium–potassium pump is too slow for this purpose.
does the all-or-none law apply to dendrites? why or why not?
the all-or-none law does not apply to dendrites, because they do not have action potentials
what happens if the depolarization does or does not reach the threshold?
if the depolarization reaches or passes the threshold, the cell produces an action potential. if it is less than threshold, no action potential arises.
when the membrane is at rest, are the sodium ions more concentrated inside the cell or outside? where are the potassium ions more concentrated?
sodium ions are more concentrated outside the cell, and potassium is more concentrated inside
when the membrane is at rest, what tends to drive the potassium ions out of the cell? what tends to draw them into the cell?
when the membrane is at rest, the concentration gradient tends to drive potassium ions out of the cell, and the electrical gradient draws them into the cell. the sodium–potassium pump also draws them into the cell.
local anesthetic
drugs that attach to the sodium channels of the membrane, stopping action potential
local neurons
neurons without an axon
myelinated axons
axons covered with insulated material composed of fat and protein
polarization
difference in electrical charges between the inside and outside of the cell
propagation of action potential
transmission of an action potential down an axon
refractory period
time when the cell resists the production of further action potentials
relative refractory period
time after the absolute refractory period that requires a stronger stimulus to initiate an action potential
resting potential
condition of a neuron’s membrane when it has not been stimulated or inhibited
saltatory conduction
the jumping of action potentials from node to node
selectively permeable
a barrier that permits some chemicals to pass more readily than others
sodium-potassium pump
mechanism that actively transports sodium ions out of the cell while drawing in two potassium
threshold
minimum amount of membrane depolarization necessary to trigger an action potential
voltage-gated channels
membrane channel whose permeability to an ion depends on the volt difference across the membrane
how many axons does one neuron have
one axon
why is an action potential a better way for an axon to transmit information than electrical conduction would be?
an action potential does not decrease its intensity over distance
when the membrane is at rest, which gradient or gradients tend to draw sodium ions into the cell?
both the electrical gradient and the concentration gradient
what causes the rising portion of the action potential?
sodium ions are moving into the cell
after the peak of the action potential, the membrane returns toward its resting level. what accounts for this recovery?
potassium ions move out because of the concentration gradient
if a membrane is depolarized to twice its threshold, what happens?
the action potential is the same as usual
the all-or-none law applies to what part of a neuron?
the axon
what causes the absolute refractory period of an axon?
the sodium channels are shut
what does the myelin sheath of an axon accomplish?
it increases the velocity of action potentials
active transport
protein-mediated process that expends energy to enable a molecule to cross a membrane
afferent axon
axon that brings information into a structure
astrocytes
star-shaped glia that synchronize the activity of the axons
blood-brain barrier
mechanism that excludes most chemicals from the brain
dendrites
branching fibers from a neuron that receive information from other neurons
efferent axon
neuron that carries information away from a structure
glia
cell in the nervous system that does not conduct impulses over long distances
interneuron
neuron whose axons and dendrites are all confined within a given structure
motor neuron
neuron that receives excitation from other neurons and conducts impulses to a muscle
nodes of ranvier
interruptions in the myelin sheath of vertebrate axons
radial glia
cells that guide the migration of neurons and the growth of axons and dendrites during embryological development
schwann cells/oligodendrocytes
glia cells that build myelin sheaths
sensory neuron
neuron that is highly sensitive to a specific type of stimulation
thiamine
a B1 vitamin necessary to use glucose
what do dendritic spines do?
they increase the surface area available for synapses
which part of a neuron has the chromosomes?
the cell body
santiago ramón y cajal clearly demonstrated which of the following?
the nervous system is composed of separate cells
what is a function of microglia?
they remove dead cells and weak synapses
under what condition do the intestinal bacteria produce more inflammatory chemicals?
under stressful conditions that might lead to depression
what is the brain’s main source of fuel?
glucose
what chemicals cross the blood–brain barrier by active transport?
glucose and amino acids
which chemicals cross the blood–brain barrier passively?
molecules that dissolve in fats enter passively. so do water and several ions for which the membrane has specific channels
why would weakened mitochondria affect the brain more than other organs?
the brain uses more energy than any other organ
of the three types of neuron—sensory, motor, and intrinsic—which would have the shortest axons?
because an interneuron is contained entirely within one part of the brain, its axon is short
how does the minimalist position differ from the abolitionist position?
a minimalist wishes to limit animal research to studies with little discomfort and much potential value. an abolitionist wishes to eliminate all animal research regardless of how the animals are treated or how much value the research might produce.
