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
rerouting
the formation of new neural connections to establish alternative neural pathways
synaptic pruning
the removal of excess neurons and synaptic connections to increase the efficient of neural transmission
Stressor
any event that causes stress or is perceived as a threat or challenge to our ability to cope
stress
a state of physiological, mental, or emotional tension, resulting from a stressor
stress as a psychobiological response
psychological- thoughts such as: “i can/can’t cope
biological-physiological responses such as increased heart rate
internal stressors
causes of stress that originate within an individual and can be both:
- psychological
- biological
external stressors
sources of stress that originate outside of an individual.
-environmental
-sociocultural
acute stress
stress that occurs because of a sudden threat that only lasts for a short time
chronic stress
involves a prolonged and constant feeling of stress.
characteristics of acute stress
-sudden or short-term
-more intense or more severe
-can be beneficial and help us with challenges (initiate the fight/flight/freeze )
characteristics of chronic stress
-ongoing, prolonged, or long term
-less intense or less severe
-generally more detrimental to health
fright/freeze/flight
an automatic, biological response to a perceived stressors that increases our chances of survival in our environment.
fight or flight
-you experience similar physiological responses, such as increased heart rate, sweaty palms and dilated pupils as a part of an acute stress response.
-activated by the sympathetic subdivision of the autonomic nervous system
freeze
freezing is a way for the nervous system to prepare to immediately shift into fight or flight action
-not considered to be a passive state the parasympathetic is dominant.
cortisiol
stress hormone is produced and released from the adrenal cortex, (the outer layer of the adrenal glands)
benefits of cortisol
-boosting our energy levels and increasing blood glucose levels
-heightening our alertness, increasing the brain’s use of glucose
-increasing the body’s ability to repair tissue
-diverting energy from non-essential bodily functions such as digestion, growth and reproduction.
Limitations of cotisol
-Cortisol suppresses the immune system, making us more susceptible to colds and contagious illnesses.
-the risk of cancer and autoimmune diseases rises
-the risk for psychiatric conditions such as anxiety and depression, increases.
enteric nervous system
division of the autonomic nervous system. consists of the nerves that line the gastrointestinal tract and control the digestive system.
the vagus nerve
one of the body’s biggest nerves, connecting the brain (CNS) to organs within the autonomic nervous system, via nerve fibers that directly link to the lungs, heart, oesophegus and the gastrointestinal tract
the vagus nerves function
The vagus nerve controls many crucial bodily functions, including mood, immune response, digestion and heart rate. It establishes one of the connections between the brain and the gastrointestinal tract
gut microbiota
the microbe population found in the gut (digestive system)
gut microbiota in relation to GABA
research indicates that neurotransmitters in the gastrointestinal tract affect the neuronal activity and cognitive functions of the brain. One study involves the neurotransmitter GABA which is the main inhibitory neurotransmitter
how does high stress change the gut microbiota?
high levels of stress results in an increased production of cortisol. if cortisol is in the bloodstream for an extended period, it leads to the breakdown of the gut microbiota that produces GABA. little GABA is known to be associated with anxiety and depression
selyes gas model
Selye’s General Adaptations syndrome
Stages of GAS (General Adaptation Syndrome)
- shock (alarm
- counter shock reaction)
- Resistance
- Exhaustion
alarm reaction
the first stage of the GAS model where an individual becomes aware of the stressor.
The alarm reaction stage does not usually last very long; sometimes just a few seconds, sometimes longer.
shock
the individual’s ability to deal with the stressor drops below the baseline and they’re unable to deal with it.
(people may faint as the BP drops quickly)
countershock
the second stage of the alarm reaction phase.
the individual’s ability to deal with the stressor rises above normal and the sympathetic nervous system is activated
resistance stage
if a stressor persists, the body enters this stage
-The body’s resources are maximized to deal with the stressor
-cortisol is produced to cope and adapt to the stressor over time, it also increases energy levels
-towards the end of this stage, physical symptoms of wear and tear appear (headaches and colds)
exhaustion
the body runs out of reserves because it has been fighting the stressor for a long time. It may become weak, and have a low resistance to physical and psychological illnesses. Energy stores become depleted due to the excess amount of cortisol in the bloodstream
benefits of GAS
-identifies various biological processes that occur as a part of the stress response
-predictable pattern that can be easily tested in a lab
limitations of GAS
-Humans and rats are physiologically different.
-does not address the various psychological processes that occur as a part of the stress response
Lazarus and Folkman’s Transactional Model of Stress and Coping
The stress response is only elicited if the individual believes that the stressor may exceed their available resources.
primary appraisal
The individual determines whether the situation or event is significant to them
-the event is categorised as either stressful or not stressful.
If deemed not to be stressful, it will be further categorised as either benign/positive or irrelevant:
irrelevent
the situation or event has no implications for the individual’s wellbeing;
benign/positive
the outcome of a situation or event is perceived as positive; that is, it either maintains (benign) or enhances their wellbeing (positive).
stressful appraisal
only if the situation is deemed stressful will further appraisal take place.
it can further be characterised into
-threat
-harm/loss
-challenge
secondary appraisal must take place
secondary appraisal
the individual considers the available resources, as well as their own coping strategies, to decide the best way of dealing with the stressor
threat
anticipated harm/loss in the future because of the event
harm/loss
damage to the individual that has already occured
challenge
perceived to have the potential for personal gain or growth
strengths for Lazarus and Folkman’s transactional model of stress and coping
the model acknowledges the psychological determinants or causes of stress response
limitations for Lazarus and Folkman’s transactional model of stress and coping
does not account for the various biological processes that occur as a part of the stress response
coping strategy
a method that people use to manage or reduce the stress produced by a stressor
factors that influence the coping strategy
coping flexibility and context-specific effectiveness
coping flexibility
our ability to modify our coping strategies to meet the demand of different stressful situations
context specific effectiveness
when their is a match or good fit between the coping strategy that is use and the stressful situation
approach strategies
confronting a stressor and dealing directly with it and its effects
benefits of approach strategies
approach strategies are generally considered to be more adaptive and effective then avoidance strategies
limitations of approach strategies
in some cases, dealing with the stressors head-on, can increase the stress levels
avoidance strategies
are used to avoid the stressor rather then deal with it directly
benefits of avoidance strategies
disengagement might be appropriate in a situation where nothing can be done
limitations of avoidance strategies
avoidance strategies tend to be maladaptive
how does the ENS communicate with the CNS
it uses bidirectional communication via the vagus nerve to send messages to and from the brain and gastrointestinal tract
