#2 u3aos1 - neurotransmitters and neuromodulators (ch3b) Flashcards
neurotransmitters
3 marks
chemical signals produced by neurons
neurons carry messages to other neurons or cells within the nervous system
two types of neurotransmitters
2 marks
GABA
glutamate
characteristics of neurotransmitters
3 marks
- release chemical signals into a single synapse
- influence is exerted rapidly
- effects last a short amount of time
synapse
2 marks
the point of communication between two neurons.
where transmission occurs
three parts of synapse
3 marks
axon terminal (pre-synaptic neuron)
synaptic gap/cleft
dendrite (post-synaptic neuron)
presynaptic neuron
the neuron sending the message
postsynaptic neuron
the neuron receiving the message
steps of how neurotransmittors are passed down
6 marks
- neurons are excited by sensory stimuli/neurotransmitters from other cells.
- action potential impulse travels along the axon terminal of the pre-synaptic neuron. (ELECTRIC IMPULSE)
- synaptic vesicles in the axon terminal release neurotransmitters into the synaptic cleft/gap. (TRANSMISSION = CHEMICAL PROCESS)
- neurotransmitters travel along the gap and bind with receptor sites + dendrites in the post-synaptic neuron.
- 2 possible results can occur:
- action potential is increased
- action potential is decreased
action-potential
2 marks
an electrical signal that excites the presynaptic neuron
helps a neuron pass down information to the axon.
diffusion
2 marks
a process where neurotransmitters drift away from the neurons instead of being passed down.
reuptake
2 marks
a process where the neurotransmitters drifting away get sucked back into the pre-synaptic neuron, back into its vesicles.
Excitatory effect
1 mark
The likelihood of post-synaptic neuron firing an action potential is increased.
Inhibitory effect
1 mark
The likelihood of post-synaptic neuron firing an action potential is decreased.
example of an excitatory neurotransmitter
1 mark
glutamate
example of an inhibitory neurotransmittor
1 mark
GABA
glutamate
2 marks
the main excitatory neurotransmitter
involved in learning and memory
characteristics of glutamate
4 marks
- increases activity of post-synaptic neurons, making them more likely to fire an action potential.
- release of glutamate causes changes in synapse associated with leanring and memory
GABA (gamma-aminobutryic acid)
2 marks
the main inihibtory neurotransmitter in the nervous system
associated with anxiety, specific phobias, and Parkinson’s disease
characteristics of GABA
4 marks
- decreases acitivty of the post-synaptic neuron, making them less likely to fire an action potential
- release of GABA has a calming effect on the nervous system (balances out the effects of glutamate’s excitatory response)
neuromodulators
2 marks
- a subclass of neurotransmitters
- regulates + influences the rate or strength of neural transmission.
the literal role of neuromodulators, how do they do their job?
4 marks.
- they increase the responsiveness of neurons, enhancing the excitatory effect.
- they decrease the responsiveness of neurons, enhancing the inhibtory effect.
2 types of neuromodulators
dopamine
serotonin
characteristics of neuromodulators
3 marks
- release chemical signals into broader areas (multiple synapse + neurons, brain area, entire neural tissue)
- influence is exerted over a slower period of time.
- effects are long-lasting
dopamine
3 marks
a multifunctional chemical in the nervous system consisting of inhibtory and excitatory effects depending on the situation.
what functions does dopamine control?
6 marks
- voluntary movement
- attention
- pleasure
- mood
- cognition
- rewards-based learning (motivation)
characteristics of dopamine
3 marks
- regulates and influences neural activity in regions of the brai associated with the functions.
- involved with pleasure, but doens’t directly cause it. It influences you to pursue behaviours/make decisions that you believe will lead to pleasure.
reward pathway
2 marks
a group of strucutres in the brain that are activated by rewarding stimuli.
how the reward pathway functions
7 marks
- when you are exposed to stimulus which is rewarding the ventral tegmental area (VTA) of the brain responds by releasing more dopamine
- dopamine is transported along the rewards pathway to other parts of the brain such as prefrontal cortex.
- more dopamine released = more the stimulus is perceived as being rewarding.
- motivation to increase the behaviour associated with the reward has increased.
examples of unhealthy + addictive behaviours of dopamine
6 marks
- over-eating
- smoking
- addiction to drugs
- excessive smartphone use
- gambling
- gaming
dopamine’s role in addiction (steps)
4 marks
- unhealthy behaviours are introduced.
- increased dopamine is relased through the rewards pathway.
- overtime, the brain becomes less sensetive to dopamine.
- urge to repeat behaviour is increased.
serotonin
2 marks
acts as an inhibitory neuromodulator, influencing varieties of behaviours.
what functions does serotonin control?
6 marks
- mood
- sleep
- memory
- impulsivity
- anger + aggression
- appetite
effect of serotonin on mood
(both) 2 marks
high levels: results to feeling good and stable mood
low levels: results to mood disorders such as anxiety and depression.
effect of serotonin on sleep
(low levels)
2 marks
low levels: leads to a reduction in sleep pressure which results in restlessness and wakefullness
4 ways to boost serotonin levels
- eat foods like banana/cashew nuts
- consume enough vitamin D, magnesium, and omega 3
- exercise for atlet 30 mins a day
- avoid alcohol + nicotine
amygdala
2 marks
an almond-shaped region in the brain associated with emotional responses.
the effect of low levels of serotonin on the amygdala
2 marks
low levels of serotonin makes it difficult for the frontal region of the cerebral cortex to regulate emotional responses of the amygdala, resulting in aggressive behaviours.
