unit 3 aos1 nervous system Flashcards
what does the human nervous system do? (+2 types)
enables the brain and the body to exchange neural messages and communicate with one another. Includes the central and peripheral nervous system)
neuron
an individual nerve cell that is specialised to receive, process and/or transmit information within the nervous system
3 types of neurons
motor, sensory and interneurons
motor neurons (efferent)
transmit neural messages about motor movement from the central nervous system to the peripheral
sensory neurons
transmit neural messages about bodily sensations from the peripheral nervous system to the central nervous system
interneurons
transfer neural messages between sensory neurons and motor neurons. the central nervous system (the brain and spinal cord) is made up of interneurons
what are the 2 types of responses the nervous system can make
conscious and unconscious
conscious responses
deliberate and voluntary actions that are intentionally initiated by the brain and performed by the body
unconscious responses
automatic and involuntary actions that are performed by the body independently of the brain in response to external and internal sensory stimuli.
the role of the central nervous system (+2 organs)
the brain and the spinal cord; processes and coordinates responses to sensory stimuli
ascending tracts
transmit sensory messages from the peripheral nervous system to the brain
descending tracts
transmit motor messages from the brain to the peripheral nervous system
3 steps of the brain as a control centre
- the brain recieves the sensory info. 2. processes it, integrates it and organises it. 3. initiates a bodily response to the skeletal muscles to respond to the stimuli.
role of the 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.
what are the 2 divisions of the peripheral nervous system
somatic and autonomic
somatic nervous system
subdivision of the peripheral nervous system that carries sensory information to the central nervous system and motor information to the body
5 steps of the conscious response
- the sensory stimulus comes into contact with sensory receptors 2. the sensory neural message is transmitted through afferent pathways to the brain 3. the brain then processes the sensory info and coordinates a conscious motor response 4. this motor neural message is then sent via efferent pathways to the skeletal muscles 5. the skeletal muscles carry out the motor response
sensory receptors
nerve endings that detect internal sensations in the body and external sensations from the environment.
the autonomic nervous system
subdivision of the peripheral nervous system that controls visceral muscles, organs and glands which are not connected to the skeleton and are predominantly self-regulating and do not require conscious control.
what are the two branches of the autonomic nervous system?
sympathetic and parasympathetic
sympathetic nervous system and its main physiological response
becomes dominant when a person is confronted with a threat or stressor. it’s main physiological response is to energise the body (preparing it to confront or escape the threat or stressor)
parasympathetic nervous system and its main physiological response
becomes dominant during rest and physical inactivity. it’s main physiological response is to maintain optimal and balanced functioning.
8 sympathetic responses
heart rate increases, breathing rate increases, pupils dilate, adrenal glands secrete stress hormones, sweat glands are activated, digestionn is inhibited, the bladder relaxes, the body releases more glucose
why does heart rate increase during the sympathetic response?
to increase blood flow as it enables high levels of physical activity
why do the pupils dilate during the sympathetic response?
to allow more light to enter the eyes, improving vision
why do the adrenal glands secrete stress hormones?
they secrete stress hormones such as adrenaline to energise the body
8 parasympathetic responses
heart beats at a steady rate, lung airways constrict, pupils constrict, adrenal glands do not secrete stress hormones, sweat glands are regulated, digestion occurs normally, the bladder constricts, the body releases less glucose
how does the heart beat during the parasympathetic response?
at a steady and regular rate that supports optimal and balanced functioning
what happens to the lungs during the parasympathetic response?
lung airways constrict enabling a steady and regular breathing rate
why does the body release less glucose during the parasympathetic response?
to allow the body to rest and prevent the depletion of energy stores
spinal reflex
an unconscious response to sensory stimuli that is initiated by interneurons in the spinal cord independently of the brain.
what is the spinal reflex’s purpose?
to protect the body from injury/harm and increase chances of survival. This is why it is an adaptive response.
3 steps of the spinal reflex
- a dangerous or harmful sensory stimulus is detected by sensory receptors and this message is sent to the spinal cord via the somatic nervous system 2. an interneuron in the spinal cord immediately relays this signal to a motor neuron, initiating an unconscious response 3. motor message is transmitted via motor neurons in the somatic nervous system to skeletal muscles
neural transmission
an electrical impulse that occurs when a neuron is activated or fires
neurochemicals
neurons communicate with one another through the release of neurochemicals. they contain the message.
2 types of neurochemicals
neurotransmitter and neuromodulator
4 steps of neurotransmission
- Neurochemicals are produced in the axon terminals of the presynaptic neuron.
- Neurochemicals are released from the axon terminals of the presynaptic neuron into the synaptic gap.
- Neurochemicals bind to receptor sites on the dendrites of the postsynaptic neuron.
- Neurochemicals affect the postsynaptic neuron, either triggering or inhibiting a response.
neurotransmitter (+2 types)
a chemical produced by neurons that carries messages to other neurons or cells within the nervous system. it directly effects change in the neuron it is binded to. exitatory and inhibitory
excitatory neurotransmitters
neurotransmitters, which have an excitatory effect on the postsynaptic neuron – more likely to fire action potential. includes glutamate
inhibitory neurotransmitters
which have an inhibitory effect on the postsynaptic neuron – less likely to fire an action potential. includes gaba
glutamate’s role in functioning
an important role in learning and memory. the excitatory effects form and strengthen synaptic connections between neurons that are repeatedly activated during learning. enables synaptic plasticity
GABA’s role in functioning
an important role in regulating post synaptic activation, preventing the overexcitement of neurons. GABA reduces anxiety by inhibiting neural signals that contribute to anxiety.
neuromodulators (+2 examples)
alters the inhibitory or excitatiory functions of neurotransmitter signals. effects change in multiple neurons and creates a long lasting response. includes dopamine and serotonin
dopamine’s effect
they can have exitatory and inhibitory effects on the post synaptic neuron depending on the type of receptor sites present at the particular brain location.
dopamine’s role in functioning
has an important role in coordinating voluntary motor movement and reward-based learning. behaviours that cause the release of dopamine include any behaviour that recieves a reward. increases motivation to undertake these reward based activities.
serotonin’s effect
inhibitory effects on the postsynaptic neuron
serotonin’s role in functioning
role in mood regulation, sleep and stabilisation. low levels of serotonin are associated with depression. role in regulating the sleep-wake cycle, therefore serotonin influences the quality and quantity of your sleep
synaptic plasticity (+2 types)
the ability of synaptic connections to change over time in response to activity or experience. changes include the formation, strengthening or weakening of synaptic connections. two forms are long term potentiation and long term depression.
long term potentiation
the long lasting and experience dependent strengthening of synaptic connections that are regularly activated at high intensity stimulation
what happens during learning and memory?
neurotransmitters are repeatedly released into the synaptic gap by axon terminals of the presynaptic neuron and recieved by receptor sites on the dendrites of post synaptic neurons.
3 structural changes during LTP
increased number of receptor sites on the postsynaptic neuron. bushier dendrites and increased synaptic connections on the postsynaptic neuron due to sprouting
long term depression
the long lasting and experience based weakening of synaptic connection between neurons that are not regularly coactivated
3 structural changes during LTD
decreased number of receptor sites of the post synaptic neuron, decreased number of dendrites and synaptic connections on the postsynaptic neuron due to pruning
3 mechanisms of synaptic plasticity
sprouting, rerouting, pruning
sprouting
the ability of dendrites or axons to develop new extensions or branches
pruning
the elimination of synaptic connections that are not adequately activated
rerouting
the formation of new connections between neurons to establish alternative neural pathways
stressor (+2 types)
any event that causes stress or is perceived as a threat and a challenge to our ability to cope. internal and external.
internal stressor
a cause of stress that originates within an individual
external stressor
a cause of stress that originates from outside an individual, such as an event or environmental extreme
stress
a state of mental, emotional and physiological tension, resulting from a stressor
what is the relationship between internal and external stressors?
an external stressor may cause internal stressors, but not always
acute stress
stress that usually occurs because of a sudden threat and only lasts for a short time. typically more intense and can be beneficial to dealing with challenges
chronic stress
stress that lasts a long time. usually less intense but more detrimental to our health
what are the two psychological stress responses?
eustress and distress
eustress
a positive psychological stress response which involves emotions such as being happy & excited. high levels of eustress prompt an increase in performance and functioning, but is temporary
distress
a negative psychological stress response which involves emotions such as being worried and upset.
2 physiological stress responses
flight-or-fight-or-freeze and cortisol
flight-or-fight-or-freeze
an involuntary and automatic response to a threat that takes the form of either escaping it, confronting it or freezing in the face of it. it is adaptive.
cortisol
In times of prolonged and chronic stress, when the stressor persists and the body continues to perceive it as a threat, another stress hormone called cortisol is produced and is released from the adrenal glands. Cortisol allows the body to continue to stay on high alert over long periods of time
general adaptation syndrome (GAS)
a biological model of stress that proposes we have a non-specific biological response to stress that occurs in three stages
3 stages of the gas model
alarm, resistance, exhaustion
alarm reaction stage
the first stage of the general adaptation syndrome, in which we become aware of the stressor; it consists of two phases – shock and countershock
shock
the first phase of the alarm reaction stage of the general adaptation syndrome, in which the body’s ability to deal with the stressor falls below normal
countershock
the second phase of the alarm reaction stage of the general adaptation syndrome, in which the body’s ability to deal with the stressor rises above normal
resistance stage
the second stage of the general adaptation syndrome, in which the stressor persists, and the body’s resources are maximised to cope and adapt over time
exhaustion stage
the third stage of the general adaptation syndrome, in which the continued depletion of energy stores and high levels of hormones such as cortisol decrease resistance to the stressor and impair the immune system
2 strengths of GAS model
- The model suggests a predictable
pattern of responses that can easily be
tested in a laboratory. - It identifies various biological
processes that occur as a part of the
stress response, such as hormone
secretion and immune system
depletion.
2 limitations of the gas model
- Humans and rats are physiologically
different. For example, human stress
responses tend to be more complex and variable. Therefore, Selye’s GAS model cannot be simply generalised to humans. - It does not acknowledge the psychological or cognitive processing involved in the human stress response, which can affect how much an individual experiences the stress response.
transactional model of stress and coping
a model that suggests a stress response is only elicited if an event is percieved to exceed our ability to cope and is based on our appraisal of the situation
appraisal
the process of categorising an event on the basis of its perceived significance and how it may affect our wellbeing
primary appraisal (+3 categories)
when an individual determines whether a situation or event is significant to them and stressful or not. if the event is not stressful, it can be classified as irrelevant and benign/positive
irrelevant
describes a situation or event that has no implications for an individual’s wellbeing because nothing will be gained or lost, or they are not invested in the situation
benign/positive
describes a situation or event that is perceived as having a positive outcome for an individual, i.e. it either maintains (benign) or enhances their wellbeing (positive)
what happens if the primary appraisal is classified as stressful?
it will be classified as threat, harm/loss and challenge
threat
the anticipated harm/loss in the future because of an event
harm/loss
the damage to the individual that has already occurred as a result of a stressor
challenge
the perceived potential for personal gain or growth from an event
secondary appraisal
when an individual considers the available resources and their own coping strategies, to decide the best way of dealing with a stressor
3 strengths of lazarus and folkman
It emphasises the personal nature and individuality of the stress response, accounting for why individual responses to an event vary widely.
The model acknowledges the psychological determinants or causes of the stress response.
It suggests that because stress involves an interaction with the environment, the individual has an active role in their own stress response and can therefore learn to respond and manage it.
3 limitations of lazarus and folkman
It is difficult to test through experimental research because of the subjective nature of individual responses to stress.
Individuals may not always be consciously aware of all the factors causing them stress or the thought processes that take place internally when experiencing stress.
It does not allow for individual variation in progression through its stages, as primary and secondary appraisals have been found to interact with one another and often occur simultaneously.
gut brain axis
the connection between the central nervous system and the enteric nervous system, that enables bidirectional communication between the brain and the gastrointestinal tract
enteric nervous system
a subdivision of the autonomic nervous system; it consists of nerve cells lining the gastrointestinal tract and controls the digestive system
vagus nerve
a nerve that connects the brain (central nervous system) to organs within the autonomic nervous system, via nerve fibres that directly link organs such as the lungs, heart, oesophagus and intestinal tract
gut
the gastrointestinal tract or long tube that starts at the mouth and ends at the anus
gut microbiota
the microbe population found in the gut (digestive system)
gut microbiome
to all of the genes of the microorganisms that live in the gut.
gut microbiota dysbiosis
When the gut microbiota is imbalanced, meaning there is not enough ‘good’ bacteria and too much ‘bad’ bacteria
gut microbiota symbiosis
when the gut microbiota is balanced. a diverse gut microbiota results in better gut health.
what is said about the composition of gut microbiota?
that emerging research suggests there are some possible connections between an individual to experience stress or to develop a mental illness due to an imbalanced gut microbiota (dysbiosis). a diverse gut microbiota results in better gut health and potentially better outcomes on the brain.
what is the relationship between stress and gut health?
During the experience of stress, the prolonged release of cortisol – the primary stress hormone – can cause damage and disruption to the digestive system which in turn may impact the experience of stress in the brain.
coping
all the things we do to manage and reduce the stress we experience
coping strategy
a method that we use to manage or reduce the stress produced by a stressor
coping flexibility
the ability to modify our coping strategies to adapt and meet the demands of different stressful situations
context specific effectiveness
when a coping strategy matches or is appropriate to the stressful situation
approach strategy
an effort to confront a stressor and deal directly with it and its effects
avoidance strategy
an effort to avoid a stressor and not deal directly with it and its effects
