Unit 3 AOS 1 Flashcards
Nervous System Functioning and Stress as a Psychobiological Process
Central Nervous System
A major division of the nervous system comprised of the brain and spinal cord. It receives sensory information from the PNS and sends motor information to the PNS.
Brain
A complex organ contained within the skull that coordinates mental processes and behaviour, and regulates bodily activity
Spinal Cord
A cable of nerve fibres that extends from the brain, connecting it to the PNS.
Peripheral Nervous System (PNS)
A major division of the nervous system comprising every neuron in the body outside the CNS
Role of the PNS
Sends sensory information to the CNS, receives motor information from the CNS
Somatic Nervous System (SNS)
A division of the PNS that transmits neural messages related to voluntary motor movement
The somatic nervous system comprises…
- sensory neural pathways, made up of sensory neurons
- motor neural pathways, made up of motor neurons
Autonomic Nervous System (ANS)
A division of the PNS that regulates visceral muscles, organs and glands and transmitted neural messages to the CNS about their activity
Visceral muscles, organs and glands
Muscles, organs and glands not connected to the skeleton that are predominantly self-regulating and do not require conscious control
e.g. lungs, heart, stomach
Sympathetic Nervous System
A division of the ANS that activates visceral muscles, organs and glands, preparing the body to respond to a threat or stressor
Parasympathetic Nervous System
A division of the ANS that maintains the optimal and balanced functioning of visceral muscles, organs and glands
Neuron
A nerve cell that receives and transmites neural information
Motor neurons (efferent neurons)
Neurons that transmit neural messages about motor movement from the CNS to the PNS
Sensory neurons (afferent neurons)
Neurons that transmit neural messages about bodily sensation from the PNS to the CNS
Interneurons
Neurons that transfer neural message between sensory neurons and motor neurons
Dendrites
Detect and receive information from other neurons
Axon
A single, tubelike extension from the soma (cell body) to the axon terminals that transmits neural information to other neurons
Conscious response
A deliberate and voluntary action that is initiated by the brain and performed intentionally by the body
Unconscious response
An automatic and involuntary action that is performed without conscious awareness
Spinal reflex
An unconscious response to sensory stimuli that is initiated by interneurons in the spinal cord independently of the brain
Neural synapse
The region that includes the axon terminals of the presynaptic neuron, the synaptic gap, and the dendrites of the postsynaptic neuron
Presynaptic neuron
The neuron that releases neurochemicals into the neural synapse (from axon terminals)
Synaptic gap
The space between the presynaptic neuron and the postsynaptic neuron
Postsynaptic neuron
The neuron that receives neurochemicals from the neural synapse (from receptor sites on dendrites)
Neurochemical
A chemical substance that transmits neural information within the nervous system (released by the presynaptic neuron)
Synaptic transmission
The chemical conveyance of neural information between two neurons across a neural synapse.
Two types of neurochemicals
- neurotransmitters
- neuromodulators
Neurotransmitter
A chemical molecule that has an effect on one or two postsynaptic neurons
Action potential
An electrical impulse that travels down the axon of a neuron
Excitatory effect
When the neurotransmitter increases the likelihood of the postsynaptic neuron firing an action potential
Glutamate
The main excitatory neurotransmitter in the nervous
Effect of glutamate
Increases the likelihood of a postsynaptic neuron firing an action potential
Glutamate’s role in functioning
Important role in learning and memory. It enables synaptic connections to form and strengthen between neurons that are repeatedly coactivated during learning
Inhibitory effect
When the neurotransmitter decreases the likelihood of the postsynaptic neuron firing an action potential.
GABA
The main inhibitory neurotransmitter in the nervous system
Effect of GABA
Decreases the likelihood of the postsynaptic neuron firing an action potential.
GABA’s role in functioning
Important role in regulating postsynaptic activation in neural pathways, preventing overexcitation of neurons. GABA reduces anxiety by inhibiting excitatory neural signals that contribute to anxiety
Neuromodulator
A chemical molecule that has an effect on multiple postsynaptic neurons
Neuromodulation
The process by which the synaptic transmission between 2 neurons is either enhanced or decreased through the action of a third substance, called a neuromodulator
Dopamine
A neuromodulator responsible for voluntary motor movement, the experience of pleasure, and reward-based learning
Effect of dopamine
It can have excitatory and inhibitory effects on the postsynaptic neuron
Serotonin
A neuromodulator primarily responsible for the regulation of mood and sleep.
Effect of serotonin
Has inhibitory effects on postsynaptic neuron
Serotonin’s role in functioning
Regulates the sleep-wake cycle. Appropriate levels of serotonin in the brain enable the experience of positive and stable moods.
Synaptic plasticity
The ability of synaptic connections to change over time in response to activity or experience
Sprouting
The ability of dendrites or axons to develop new branches.
- This enables formation of new synaptic connections
Rerouting
Ability of a neuron that is connected to a damaged neuron to create an alternative synaptic connection with an undamaged neuron
Pruning
Elimination of synaptic connections that are not adequately activated
- necessary to accommodate more essential synaptic connections, thus enhancing efficiency of brain functioning
Learning
The process of acquiring knowledge, skills or behaviours through experience
Memory
The process of encoding, storing and retrieving information that has been previously encountered
Long-term potentiation (LTP)
The long-lasting and experience-dependent strengthening of synaptic connections that are regularly coactiviated.
How is LTP an experience-dependent form of synaptic plasticity?
Because neural synapses are strengthened in response to frequent and repeated use during learning and memory
Structural changes that occur due to LTP
- increased number of receptor sites on dendrites of post-synaptic neuron
- increased number of synaptic connections between neurons (sprouting)
- bushier dendrites on postsynaptic neuron (sprouting)
Long-term depression (LTD)
The long-lasting and experience-dependent weakening of synaptic connections between neurons that are not regularly coactivated
How is LTD an experience-dependent form of synaptic plasticity?
Because neural synapses are weakened in response to infrequent use
Structural changes that occur due to LTD
- decreased number of receptor sites on dendrites of postsynaptic neurons
- decreased number of dendrites on postsynaptic neurons (pruning)
How is the weakening of connections due to LTD a good thing?
Enables the brain to focus on more necessary neural pathways that represent more useful information
Stress
A psychological and physiological experience that occurs when an individual encounters something of significance that demands their attention and efforts to cope
Stressor
A stimulus (internal or external) that prompts the stress response
Why is stress considered a psychobiological process?
There are psychological components, which include an individual’s personal assessments of what constitutes a stressful situation, and biological components, which relate to the body and how it responds to stress
Internal stressor
A stimulus from within a person’s body that prompts the stress response
Examples of internal stressors
Rumination (repeatedly thinking about the negative components of an event), low self-esteem, attitude
External stressor
A stimulus from outside of a person’s body that prompts the stress response
Eustress
A form of stress characterised by a positive psychological state
Distress
A form of stress characterised by a negative psychological state
Acute Stress
A form of stress characterised by intense psychological and physiological symptoms that are brief in duration
Fight-or-flight-or-freeze response
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
Chronic stress
A form of stress that endures for several months or longer
Cortisol
A hormone that is released in times of stress to aid the body in initiating and maintaining heightened arousal
General Adaptation Syndrome (GAS)
A biological model involving 3 stages of physiological reactions that a person experiences in response to a persistent stressor
Alarm reaction
The first stage of GAS involving the initial decrease and subsequent increase in bodily arousal in response to an immediate stressor
Shock
The first substage of the alarm reaction stage involving decreased bodily arousal for a brief period of time following the initial exposure to a stressor
Counter shock
The second substage of the alarm reaction stage in which sympathetic nervous system responses occur that energise the body to respond to a stressor
Resistance
The second stage of GAS involving maintaining high levels of bodily arousal in response to a persistent stressor
Exhaustion
The third stage of GAS involving the depletion of energy levels and bodily resources, resulting in an inability to cope with the stressor
What does the Transactional Model of Stress and Coping propose?
That individuals experience stress when their available coping resources outweigh the demands of the stressor
Primary Appraisal
The initial process of evaluating the nature of an incoming stressor, specifically the kind of stress it might cause
Benign-positive
An initial appraisal of a stimulus as neutral, or good that does not cause stress for the individual
Irrelevant
An initial appraisal of a stimulus as a non-issue for the individual − the stimulus does not cause stress
Stressful
An initial appraisal of a stimulus as a source of worry or emotional significance for the individual
Harm/loss
A further appraisal of a stressor as having caused some damage to the individual
Threat
A further appraisal of a stressor as potentially causing damage to the individual in the future
Challenge
A further appraisal of a stress as potentially providing a positive opportunity for growth or change for the individual
Secondary appraisal
The process of evaluating the resources required and available in order to cope with a stressor
The gut-brain axis
The bidirectional connection between the gut and the brain through the enteric and central nervous systems
Gut microbiota
All of the microorganisms that live in the gut
Gut microbiota symbiosis
When the gut microbiota is balanced
Gut microbiota dysbiosis
When the gut microbiota is imbalanced
Vagus nerve
A column of nerve fibres that connects the brain and the gut
Role of the vagus nerve
Bidirectionally conveys information between the gut and the brain. Controls vital bodily functions including mood, immune response and digestion
Coping
The process of dealing with stress
Context-specific effectiveness
When the coping strategy or mechanism used is appropriate for the unique demands of the stressor
Coping flexibility
An individual’s ability to adjust or change their coping strategies depending on the unique and changing demands of a stressor
Coping strategies
The ways that people deal with stress
Approach strategies
Coping strategies that directly confront the source of stress
Avoidance strategies
Coping strategies that evade the stressor, seeking to indirectly reduce stress.
