Chapter 3 Flashcards
explain materialism
behaviour can be fully explained by the working of the brain and the rest of the nervous system without any need to refer to the mind
explain mentalism
of the mind; an explanation of behaviour as a function of the mind
stimulus to physiology is the ______. Physiology to perception is ________
causation.
correlation
brain and behavior are related how?
the brain affects behaviour and behaviour affects the brain
neurons
the basic structural and functional units of the nervous system
glial cells make up how much of the brain
50%
how many glial cells are there for every 1 neuron
10
what do glial cells do
support, nourish neurons and remove their waste
what are the three types of neurons
motor neuron
interneuron
sensory neuron
what is the function of a neuron
receive, integrate and transmit information
what neuron receives the stimulus
sensory neuron
what neuron is the effector
motor neuron
what are the three parts of all neurons
cell body (soma)
dendrites
axon
function of the dendrites in a neuron
to receive information
describe the axon and what it does
a long, thin fibre that transmits signals away from the cell body to other neurons, muscles, or glands
where is the cell body in the sensory neuron
middle (between schwann cell and myelin sheath)
Axons are always wrapped in myelin sheath
not all but many
what does myeline sheath do
speeds up signal transmission along an axon
what is myeline sheath derived from
glial cells
degeneration of myelin sheath will lead to
- ineffective signal transmission
- multiple sclerosis
- loss of muscle control
- weakness and paralysis
- vision difficulties
an axon end in a ______ ______. which is filled with
terminal button filled with neurotransmitters (a kind of chemical messengers)
the cell membrane of n axon is
semipermeable
The connection between two neurons or a neuron and an effector is called
a synapse
Na and K are pumped in what manner across the membrane in different rates?
back and forth
what does the different in flow rates of Na and K across the membrane do
slightly higher concentration of negatively charged ions inside the cell
what is the resting potential of an axon
-70 millivolts
The action potential
is a sudden change in voltage. when a neuron is stimulated a brief jump occurs, spike can be observed on the voltmeter
what happens in resting potential
NA/K pump
what happens in deploraization
voltage-gated Na channel (allowing Na to rush in)
- negativity of the membrane potential is reduced
what happens in repolrization
voltage gated K channel
Depolarization in myelinated neurons means that action occurs only in
nodes of Ranvier
In depolarization, the negativity of the membrane potential is _____ (increased or decreased)
decrease, making it less negative
A depolarization between -70mV and -55mV shows what effects
none
when the negativity of a membrane potential. is reduced to less than ____ mV, an action potential occurs
-55mV
Repolarization is when
the transmembrane potential reaches 35mV, and the voltage-gated Na+ channels close while the voltage-gated K channels open, allowing K to rush out the membrane
During repolarization the negativity of the membrane potential ____ (increases or decreases)
increases, making it more negative
The membrane potential overshoots to ___ mV (in repolarization) when the K channels close before returning to resting position of -70mV
-90mV
Absolute Refractory Period
The time in between firing neuron action potentials
(last 1 to 2 milliseconds)
Relative Refractory Period
a time when neurons can fire, but their threshold for firing is elevated, making a more intense stimulation required to initiate an action potential
The All or None Law
neural impulse is an all-or-none proposition, the neuron either fires or doesn’t. That means when it fires, the action potentials are all the same (a weaker stimuli does not produce a smaller action potential)
according to the all-or-nothing law, a stronger stimulus will cause neurons to
fire more frequently than a weaker stimulus
According to the all-or-none law, thicker axons transmit impulses ____ than thinner ones do
more rapidly
what is a synapse
connection between the end of the axon of one neuron and the dendritic spine of the other neuron
Excitatory transmitters cause
depolarization
excitatory transmitters increase or decrease the likelihood of an action potential
increase (inside of receiving neuron becomes more positive)
Inhibitory transmitters causes
hyperpolarization
inhibitory transmitters increase or decrease the likelihood of action potential
decrease (inside of a receiving neuron becomes more negative)
in the case of a Convergent synaptic transmission
a post-synaptic neuron receives signals from multiple pre-synaptic neurons some are excitatory (positive) and some are inhibitory (negative). the summation of the strengths and directions will produce a graded (not all or nothing) post synaptic potential
when a neurotransmitter and a receptor molecule combine reactions in the cell membrane cause a
postsynaptic potential (PSP)
- a voltage change at a receptor site on a post-synaptic cell membrane
Postsynaptic potential (PSP) follows the all or none law . t or f
false because it is a summation of many signals from the pre-synaptic neurons
Excitatory PSP (EPSP) has a ____ voltage shift, which does what to the likelihood that the postsynaptic neuron will fire action potentials
positive shift, which increases the likelihood that the postsynaptic neuron will fire action potential
Inhibitory PSP (IPSP) is a ____ shift, which does what to the likelihood that the postsynaptic neuron will fire action potentials
negative which decreases the likelihood
what is dopamines function
to influence movement, learning, and attention and emotion
what is serotonin functions
affects mood, hunger, sleep, and arousal
explain dopamine malfunctions
excess dopamine receptor activity linked to schizophrenia; when starved of dopamine the brain produces the tremors and decreased mobility of Parkinson’s disease
example the malfunctions of serotonin
undersupply linked to depression; Prozac and some other antidepressant drugs raise serotonin levels
Explain the dopamine hypothesis of schizophrenia
amphetamine and cocaine create schizophrenia-like symptoms by increasing dopamine activity at the dopamine synapses acting as an agonist
explain agonist
a drug that mimics or enhances the effect of a neurotransmitter
explain Antagonist with an example
a drug that blocks or reduces the effects of a neurotransmitter. Chlorpromazine is used to reduce the symptoms of schizophrenia
plasticity of synapses means
the capability of change in response to environment or learning which synapses can do
what invokes the plasticity of synapses. what are the three different ways they can change
repetitive exposure to the same stimulus can bring long-lasting change in synapses
1. they can change the release of neurotransmitters
2. they can grow new synaptic connections
3. they modify their structures
what produces changes in the neurotransmitter release
learning two types
1. habituation - a simple form of learning in which the strength of a response to a certain stimulus becomes weaker with repeated presentations of that stimulus
2. sensitization - an enhanced response to a stimulus
habituation explained
calcium channels become less responsive to voltage changes. the influx of calcium in response to an action potential decreases, resulting in fewer neurotransmitters released at the presynaptic membrane, therefore less depolarization of the postsynaptic membrane
sensitization explained
Sensitization makes the K channels less responsive and slower to open. This prolongs an action’s potential, which results in more Ca influx and increased transmitter release. more neurotransmitters released at the presynaptic membrane. greater depolarization of the postsynaptic membrane
explain why sensitization is the opposite of habituation
in sensitization, the change takes place in the potassium channels and then calcium channels. in habituation it takes place in the calcium channels
frontal lobe function
thinking, memory, behaviour, and movement
parietal lobe function
language and touch
temporal lobe function
hearing, learning and feelings
brain stem function
breathing heart rate and temperature
occipital lobe function
sight
cerebellum function
balance and coordination
hypothalamus function
regulates body function
amygdala function
emotion
basal ganglia function
movement and reward
thalamus function
sensory gateway
hippocampus function
memory
