Unit 3 AOS 1 Flashcards
How does the nervous system enable psychological functioning?
List the 2 major divisions of the nervous system
CNS (Central nervous system) + PNS (peripheral nervous system)
What is the function of the CNS?
process info from internal & external environment & formulates responses, receives sensory info -> PNS, sends motor info from PNS
What is the structure of the CNS and what are they each responsible for?
Brain
- regulates & guides the ns
- responsible for higher order functions (e.g. thinking) & vital body functions (e.g. breathing)
spinal cord
- route between brain and body
- afferent & efferent tracts
What is the function of the PNS?
Transmits neural msgs between CNS and body
What is the structure of the PNS (+ 2 subdivisions) and what are they responsible for?
made up of all the neurons outside of brain and spinal cord
Somatic NS
- transmits neural info relating to voluntary motor movement
- afferent & efferent tracts
Autonomic NS
- regulates visceral (self-regulating & connected to skeleton) MOG (muslces organs and glands)
- transmits info on MOG activity to CNS
What are the 2 subdivisions of the ANS and what are they responsible for?
Sympathetic NS
- activates visceral MOG in response to stressor
- e.g. fight flight freeze response
Parasympathetic NS
- counterbalances SNS
- maintains optimal balance of visceral MOG
Define neuron
a nerve cell that receives and transmits neural info
List the 2 types of neurons and their function
Sensory (afferent)
- transmit neural msgs ab bodily sensations from PNS to CNS
Motor (efferent)
- transmit neural msgs on motor movement from CNS to PNS
Interneurons
- transfer neural msgs between sensory & motor neurons
What is a conscious response?
deliberate, voluntary brain initiated by brain (CNS) & performed by body (PNS)
List the step-by-step process for a conscious response
sensory receptors detect sensory stimulus -> sensory neural message transmitted via afferent pathways -> SNS -> brain -> spinal cord -> brain processes sensory info (coordinate & initiates motor response) -> motor neural msg trasmitted via efferent pathways -> spinal cord -> SNS -> skeletal muscles where motor movement is carried out
What is an unconscious response?
automatic & involuntary actions performed by body independently of brain
What are the 2 types of unconscious responses & explain them
Physiological
- sympathetic response (increased heart rate, adrenaline secretion, breathing rate, glucose for energy, pupils dilating 4 more light w better vision & suppressed bodily functions like thirst, digestion,)
- parasympathetic response (e.g. heart rate returning to normal)
Spinal reflex
- automatic response initiated by spinal cord neurons independently of brain
- occurs during pain and survival
describe the step by step process for a spinal reflex
sensory receptors detect harmful sensory stimulus -> sensory neural message is transmitted via afferent pathways in the SNS -> spinal cord -> interneuron in spinal cord immediately relays sensory signal from sensory neuron -> motor neuron initiating motor response -> motor msg transmitted by motor neurons in SNS -> skeletal muscles that carry out unconscious motor response -> sensory msgs travels via afferent tracts in the spinal cord -> brain, then registeres sensation that triggered spinal reflex
define the reflex arc
path along which the neural signal is transmitted as poart of spinal reflex
What energy do transmissions between neurons (presynaptic -> postsynaptic) use?
Chemical energy
What energy do transmissions within neurons use?
Electrical energy
List the structure of a neuron & define each structure
Dendrite
- receives incoming neural messages
Soma
- body of the neuron, containing nucleus w genetic material for neuron
Axon
- pathway which neural message travels down
Myelin sheath
- fatty tissue encasing axon to aid in transmission speed
Axon terminals
- exit pathways for neural msgs to transmit to next neuron
Terminal buttons/synaptic knobs
- release neurotransmitters to postsynaptic neuron for communication purposes
What is a presynaptic neuron?
neuron releasing neurochemicals into neural synapse
What is a postsynaptic neuron?
neuron receiving neurochemicals from neural synapse
What is a neural synapse?
region containing axon terminals of presynaptic neuron, synaptic gap & dendrites of postsynaptic neuron
Explain what neurochemicals are & list the 2 types
- chemical substance transmitting neural info within NS
- produced in presynaptic neuron’s axon terminals
- released from presynaptic neuron’s axon terminals into synaptic gap
- either trigger/inhibit response on postsynaptic neuron
- bind to receptor sites on dendrites of postsynaptic neuron
Neurotransmitters & neuromodulators
Explain the lock & key analogy
neurochemicals are the key and receptor sites are the lock, since specific keys only work on specific locks, therefore specific neurochemicals can only bind on corresponding receptor sites to activate response
Explain what neurotransmitters are & the 2 types (give an example for each of the types & describe)
chemical molecule that effects 1/2 postsynaptic neurons
- Glutamate (excitatory): important role in learning & memory thru strengthening synaptic connections in neurons repeatedly activated during learning, causing memories for what has been learnt. Enables synaptic plasticity
- GABA (inhibitory): prevents overexcitation of neurons thru regulating activation of postsynaptic neurons, can prevent seizures, reduce anxiety
Define what an action potential is
electrical impulse that travels down the axon of a neuron, enhancing neural transmission thru activating postsynaptic neurons, making it more likely for the effect to happen
Explain what neuromodulators are & list 2 examples
- chemical molecule that has an effect on multiple postsynaptic neurons (bigger version of neurotransmitters)
Serotonin (inhibitory) and Dopamine (inhibitory & exhibitory)
Identify & describe the 2 types of effects of neurochemicals
Inhibitory effect
- decreases the likelihood of postsynaptic neuron firing action potential
Excitatory effect
- increases likelihood of postynaptic neuron firing an action potential
Describe the function of the neuromodulator serotonin (3 main roles)
- inhibitory effect
- produced in brainstem & travels to almost all of cerebellum
3 main roles:
Mood
- high levels = improved
- balanced = calm, focus, stable, happy
- low = devastating effect on mood regulation (e.g. insomnia, anxiety)
Sleep
- low levels = disrupted circadian rhythm, restlessness & wakefulness @ wrong times
Aggression/Impulsivity
- low levels = more likely 2 be impulsive, choose immediate reward over delayed potentially larger reward
- low levels = affected communication between structures regulating emotions
- higher levels = reduced impulsivity, waiting longer for rewards
Describe the function of the neuromodulator dopamine (3 main roles)
- involved in drive, motivation & motor movement
- both inhibitory & excitatory
3 main roles
Thirst & drinking
- feelings of pleasure released when drinking liquid, encouraging repeat
Hunger & eating
- feelings of pleasure released when eating, increasing chances of eating food next time hungry
- brain receives signals from hormones indicating hunger
Addiction
- associated w unhealthy behaviours (e.g. gambling, drinking, smoking)
- caused from inability from brain to produce dopamine naturally without behaviour/substance individual is addicted to
Define neuroplasticity & list the 2 types
Brain’s ability to physically change in response to experience
2 types:
Developmental
- occurring naturally across lifespan
- certain critical periods enable greater developmental plasticity
Adaptive
- occurs as result of brain damage or trauma
- utilising critical periods in developmental plasticity enables greater adaptive plasticity
Define synaptic plasticity
the ability of synaptic connections to change over time in response to activity or experience
List & explain the 3 mechanisms of synaptic plasticity
Sprouting
- ability of dendrites/axons to develop new extensions/brances
Rerouting
- ability of neuron attached to damaged neuron to create an alternative synaptic connections w undamaged neuron
Pruning
- elimination of less activated synaptic connections
List the 2 processes that synaptic plasticity is fundamental for, and list the 2 forms that underlie it
Fundamental for learning & memory
2 forms underlying it
LTP (long term potentiation) & LTD (long term depression
Define learning
process of acquiring knowledge, skills, behaviours thru experience
define memory
process of encoding, storing, retrieving info previously encountered
Explain what LTD (long term depression) is & list its structural changes
- long lasting & experience-dependent weakening of less activated synaptic connections
- decreases efficiency of synaptic transmission on that neural pathway
- involves pruning
Structural changes:
- decreased no. of receptor sites on dendrites of postsynaptic neuron
- decreased no. of dendrites on postsynaptic neuron
- decreased no. of synaptic connections between neurons
Explain what LTP (long term potentiation) is & list its structural changes
- long lasting & experience-dependent strengthening of regularly activated synaptic connections to increase efficiency of synaptic transmissions on that neural pathway
- involves sprouting
Structural changes:
- increased no. of receptor sites on dendrites of postsynaptic neuron
- bushier dendrites on postsynaptic neuron
- increased no. of synaptic connections
Define stress
psychological & physiological reaction occurring when an individual encounters something of significance that demands attention/efforts to cope
Define stressor & the 2 different types
external/internal stressor prompting stress response
Internal:
- stimulus from within person’s body
- e.g. attitude, low self-esteem, nervous system dysfunction
- cognitive & biological processes
External
- Stimulus from outside a person’s body that prompts stress response
- e.g. test/exam, meeting new people, arguments w ppl
- environmental stimuli
List & explain the 2 psychological stress responses
Distress
- characterized by a negative psychological state
- e.g. losing keys to the car
Eustress
- characterized by a positive psychological state
- e.g. offered a place at uni, tho stressful it results in positivity, like feeling motivated and excited for personal growth
Define acute stress
characterized by intense psychological & physiological symptoms that are brief in duration
Define chronic stress
form of stress that endures for several months or longer
Identify the 2 physiological stress responses
fight/flight/freeze response to acute stress & role of cortisol
Explain the fight-flight-freeze response to stress
involuntary & automatic response to threat, involving arousal of sympathetic NS (e.g. adrenaline production)
Fight:
- involves confronting stressor
Flight:
- involves fleeing from stressor
Freeze:
- body’s immobility and shock in response to stressor
Explain the role of cortisol as a stress response & define cortisol
Cortisol: hormone released in times of stress to aid body in initiating and maintaining heightened arousal
Role:
* increasing blood sugar levels
* improving metabolism
* energising the body
* reducing inflammation
What are the negative effects of a prolonged period of stress due to cortisol
- immunosuppression
- weakens immune system
what is the enteric nervous system a further division of
autonomic nervous system
what is the function of the vagus nerve
relays msgs between the gut and brain as part of the gut-brain axis
‘define the flight fight freeze response
involuntary & automatic response to a stressful stimuli involving fleeing from it, confronting it or freezing in face of it
