aos 1 Flashcards
CNS
consists of the brain and spinal cord
CNS main function
process info received from the internal and external environment
- activate appropriate response
CNS- the brain
receives and processes sensory information from the body, initiates responses, controls all bodily actions
The spinal cord
a composed of a dense bundle of nerve fibres and is directly linked to the peripheral nervous system by 31 pairs of spinal nerves.
spinal cord processes
Provides two-way communication to and from the brain,
-sends sensory information up to brain
-sends motor information down to muscles
peripheral nervous system
all the nerves outside of the central nervous system that carry messages between the central nervous system and muscles, organs and glands throughout the body
somatic nervous system
a subdivision of the peripheral nervous system that carries sensory information to the central nervous system and motor information to the body
autonomic nervous system
a subdivision of the peripheral nervous system that controls the body’s internal environment in an unconscious or self-regulated manner
sympathetic nervous system
a subdivision of the automatic nervous system that increases our arousal, readying the body for a quick response
parasympathetic nervous system
a subdivision of the automatic nervous system that controls the bodies internal environment
it returns the body to a clam state after a threatening or stressful situation
unconscious response
any response of our nervous system that does not require awareness unconscious responses tend to be unlearned; for example we are born with the ability to blink because it is innate
conscious responses
any response of the nervous system that requires awareness
for example putting on a jacket when cold
Neurotransmitters
a chemical produced by neurons that carries messages to other neurons or cells within the nervous system, including muscles, organs, and glands
excitatory neurotransmitters
increase the likelihood that the post-synaptic neuron will fire an action potential or neural impulse.
the main excitatory neurotransmitter is GLUTAMATE
inhibitory neurotransmitters
s decrease the likelihood that the post-synaptic neuron will fire an action potential or neural impulse,
the main inhibitory neurotransmitter is GABA
Too little GABA can cause
the excitatory effects of glutamate take over, leading to mental disorders such as anxiety. or seizures
too little Glutamate can lead to
the inhibitory effects of GABA can take over, leading to mental disorders such as depression
major nerves that send sensory info to the brain
vagus nerve, olfactory nerves and optic nerve
Glutamate’s role
it plays an important role in learning and the formation of memories in the brain, by stimulating essential structural and functional changes to the connections between neurons
GABA’s role
suppresses or slows down postsynaptic neuron activity, and reduces the likelihood of them firing.
it also plays a role in counteracting glutamate and balancing the excitatory effects.
Neuromodulators
a subclass of neurotransmitters that alter the neural transmission of neurons by controlling the synthesis and release of neurotransmitters
differences between neurotransmitters and neuromodulators
-neurotransmitters fire from 1 to another
-neuromodulators are targetted to multiple neurons
-NT short-acting/Quick
-NM is longer lasting but takes longer to spread
examples of neuromodulators
dopamine and serotonin
dopamine’s funcions
it is involved in many CNS functions in addition to pleasure, such as movement, attention, mood, cognition and motivation
-associated with the reward pathway
the reward pathway
The pathway controls our responses to natural rewards, such as food, sex, and social interactions, and is, therefore, an important determinant of motivation.
dopamine in relation to food and motivation
- dopamine levels decrease below the baseline in the reward pathway in the brain.
- this results in sensations such as hunger
- increase in food-seeking behaviour
- when you eat, Dopamine levels in the brain increase above the baseline.
- pleasure is experienced reinforcing this pattern of brain activity and behaviou
dopamine role in addiction
unhealthy behaviour such as gambling or gaming
->increased dopamine released in the reward pathway, producing feelings of pleasure.
-> Over time, less dopamine is produced, diminishing the brain’s supply.
->continues the behaviour such as gaming or gambling to seek out the feeling of pleasure.
Serotonin
a neuromodulator, influencing a variety of brain activities. Interestingly, more than 90% of the body’s serotonin is found in the gastrointestinal tract
serotonin function
it modulates virtually all human behavioural processes, including mood, anger, aggression and appetite
impairments to the serotonin pathway system have been linked to depression
serotonin’s role in mood
research shows that when serotonin levels are high, mood improves. there is also an association between low serotonin levels and depression.
role of serotonin in sleep
Research has also shown that lower levels of serotonin in the brain can also disrupt the circadian rhythm of sleep-wake cycles
the role of serotonin in impulsivity and aggression
Research shows that serotonin helps regulate brain activity associated with impulsive and aggressive behaviours.
lower levels of serotonin
it has been shown that a lower level of serotonin in the brain, leads people to discount a delayed reward, increasing impulsive and aggressive behaviours
long term potentiation
a relatively permanent strengthening of synaptic connections resulting from repeated activation of a neural pathway
long term depression
it involves a relatively permanent weakening of synaptic connections.
This is usually a result of repeatedly lower levels of activity in a neural pathway
sprouting
-growth of additional axon sprouts called filigree appendages on the axon terminals of the presynaptic neurons
- growth of dendritic spines on the dendrite of the postsynaptic neuron.
-formation of additional synapses where these dendritic spines and filigree appendages meet, referred to as synaptogenesis