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

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.**

3) 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.