Psych unit 3 AOS1: how does the nervous system enable psychological functioning?

Central nervous system (CNS)

Central nervous system (CNS)

-Receives and processes sensory info from the body’s INTERNAL & EXTERNAL environments → to coordinate a response.

-Comprises of the brain and spinal cord.

Brain (CNS)

-Control centre of the entire NS.

-Responds to sensory info & is responsible for everything that we think/do.

Spinal cord (CNS)

-Connects brain & peripheral NS.

-Receives sensory info from the body & carries the messages to the brain for processing.

-Motor info from brain is carried to organs/glands via peripheral NS.

-Initiates involuntary spinal reflex.

Peripheral nervous system (PNS)

-Carries info about body’s peripheral & external environments towards the CNS.

-Carries info from CNS to the muscles, organs & glands.

Somatic nervous system (PNS)

-Carries motor info from CNS to skeletal muscles → signals them to expand/contract.

-Carries sensory info from receptor sites towards CNS to enable voluntary coordinated response to stimuli.

Autonomic nervous system (PNS)

-Connects the CNS to the body’s internal organs & glands (self-regulating).

-Changes visceral muscles, organs & glands in response to demands placed on the body.

Sympathetic nervous system (ANS)

-Increases activity of internal muscles, organs & glands to prepare body for action or a stressor.

-Eg. increased heart beats, increased secretion of glucose in liver (energy), dilated pupils, expanded airways.

Parasympathetic nervous system (ANS)

-The counter-balance activity of the sympathetic NS.

-Helps restore body to its normal state after action/stressor.

-Eg. constricted pupils, resting heartbeat, constricted airways.

Enteric nervous system (ANS)

-Monitors physiological conditions of the digestive tract.

-Integrates digestive tract’s info about its muscle contractions, gastric acid secretion and blood flow.

-Can function independently of the brain.

Conscious response

-Reaction to sensory stimuli that involves awareness (voluntary).

-Eg. shielding your eyes when its too sunny.

Unconscious response

-Reaction to sensory stimuli that doesn’t involve awareness (involuntary).

-Eg. blinking when eyes get too dry.

Spinal reflex

-Unconscious and automatic response controlled by nerual circuits in the spinal cord.

-Reflex arc: sensory info is reflected back from the spinal cord.

-Helps body react quickly to pain.

Neurotransmitter

-Chemical substance produced by a neuron that carries a message to other nearby neurons.

Synaptic gap

-Tiny space b/w axon terminals of presynaptic neuron and dendrite of postsynaptic neuron.

1. Excitatory - stimulates a postsynaptic neuron to perform its functions.

2. Inhibitory - blocks/prevents a postsynaptic neuron from firing and functioning.

Glutamate

-Main excitatory neurotransmitter in CNS → enhances info transmission (postsynaptic ready to fire).

Gamma-amino butyric acid (GABA)

-Main inhibitory neurotransmitter in CNA → makes postsynaptic less-likely to fire.

Neuromodulator

-A neurotransmitter that works/influences with other neurotransmitter.

-Can affect a large number of neurons at the same time.

Dopamine

-Modulatory neurotransmitter (mainly excitatory) with main functions of: moving, learning and behaviour that’s ‘rewarding’.

-Produced in Substantia Nigra.

Serotonin

-Inhibitory modulatory neurotransmitter with functions such as: mood, emotions, processing, sleep and pain.

-Can be described as ‘mood stabiliser’ → keeps us calm, positive and prevents anxiety.

Synaptic plasticity

-Ability of the synapse to change in response to experience.

-Strengthening/weakening of connections b/w neurons at a synapse.

-SYNAPSE IS SMALL AREA B/W 2 NEURONS.

Sprouting

-Creations of new extensions on a neuron to allow new connections with other neurons.

Rerouting

-New connections are made b/w neurons to make alternative neural pathways.

Pruning

-Elimination of weak, imperfect or unused synapses.

-Synaptic gap is destroyed.

Hebb’s rule

-Neurons that fire/wire together. Presynaptic & presynaptic neurons can be so closely/tightly linked & frequently used = the fire at the same time (more efficient).

Long-term potentiation

-Long-lasting enhancement of synaptic transmission due to repeated strong transmission.

-Enables postsynaptic neurons to be more easily activated.

-Enhances memory storage of info.

Long-term depression

-Long-lasting decrease in the strength of synaptic connections & transmission.

-Results from a lack of stimulation of pre/postsynaptic neurons.

-The basis of blocking/erasing unwanted thoughts, feelings and behaviours.

Stress

-A psychological/physiological response produced by internal OR external stressors.

Stressor

-Stimulus that produces stress.

-Can be physiological (noise, temp) or psychological (running late).

Internal stressor

-Originates from the individual (personal problems or physical pain).

-Eg. stomach pain or anxiety.

External stressor

-Originates outside the individual from environmental factors.

Eg. having too much homework.

Acute stress

-Stress that lasts for a short amount of time.

Chronic stress

-Stress that lasts for a prolonged period of time.

Flight-or-flight-or-freeze response

-An involuntary, bodily response to a sudden and immediate threat in readiness to fight (confront), flight (run away) or freeze (be silent and unseen).

-Fight-flight uses sympathetic NS → increased heart rate etc.

-Freeze uses parasympathetic → movements stop.

Cortisol

-Primary stress hormone which acts slowly but effects are long-lasting on stressors.

-Sourced by the adrenal cortex.

-Can shut down functions not needed to deal with stressor (reproductive system).

-Immediate effects in response to stressor is energising body (secretion of glucose in liver).

Having excessive cortisol

-Impaired immune system (vulnerable to disease).

-Weight gain (increased appetite).

-Physiological: high blood tension, digestive problems, heart attack and strokes.

-Psychological: impaired cognitive performance, impaired memory & learning difficulties.

Gut-brain axis (GBA)

-Bidirectional neural pathways that enable communication b/w bacteria in gastrointestinal tract and the brain.

-Vagus nerve helps the communication (neurotransmitter) between the gut & brain.

-Chronic stress affects gut microbiome → illness.

Gut microbiota OR microbiome

-Highly diverse and dynamic system of trillions of bacteria & other microorganisms that live in the gastrointestinal tract.

-Disruptions to gut microbiota such as infections can trigger reactions in the body that affects physiological & psychological health.

-Affects gut and brain → even your health!

General adaptation syndrome (GAS)

-A 3-staged physiological response to stress.

1st stage → alarm reaction

2nd stage → resistance

3rd stage → Exhaustion

Alarm reaction (stage 1 of GAS)

-Occurs when individual initially becomes aware of stressor.

1. SHOCK happens → drop in blood pressure, body temp and muscle tone.

2. Body rebounds from shock into COUNTER SHOCK → sympathetic NS (fight/flight) is activated, highly aroused & alert, adrenaline is released into blood stream.

-Helps maintain defensive reaction to stressor (high alertness & readiness).

Resistance (stage 2 of GAS)

-Occurs when stressor is not initially dealt with → body copes & adapts to the stressor.

-Unnecessary physiological processes shut down (digestion, menstruation, sex drive).

-Cortisol goes into blood stream to energise body.

-High levels of cortisol = weakened immune system.

Exhaustion (stage 3 of GAS)

-Occurs when stressor is still present after 2nd stage.

-Prolonged stress → depleted resources, resistance to disease lowers, vulnerable to physical & mental problems.

-Symptoms → extreme fatigue, high anxiety, depression, nightmares, impaired sexual performance.

-High cortisol level in blood stream = physical tear & wear on organs dealing with stress.

-Physical disorder → hypertension, stomach problems, heart disease & potentially death.

Lazarus and Folkman’s Transactional Model of Stress & Coping

-Proposes that stress involves an encounter between an individual and their environment, and that a stress response depends upon both an individual’s appraisal of the stressor and their ability to cope with it

Coping

-Cognitive & behavioural efforts to manage specific internal/external stressors.

Approach strategies

-Effort to cope with stress by confronting the stressor & dealing directly with it.

Eg. stressed on upcoming exams so you study daily to ensure that you’re prepared.

Avoidance strategies

-Effort to cope with stress by evading the stressor & indirectly dealing with it.

Eg. stressed on upcoming exams so you avoid it by playing video games.

Coping flexibility

-Ability to effectively modify or adjust one’s coping strategies according to the demand of stressor.

Context-specific effectiveness

-When there is a match or ‘good fit’ between the coping strategy & the stressor.

Eg. upcoming sac, a positive coping strat is to study.