UNIT 3 AOS1 Flashcards
What are the 3 main roles of the Nervous System?
Reception
Processing
Response
Reception.
Receives sensory stimuli. Internal and external. eg heart rate.
Process
Making sense or interpretation.
Respond
Physical action. eg using skeletal muscle - internal muscle.
eg. sweat.
Central Nervous System.
- Brain
- Spinal cord ( Spinal Reflex )
Peripheral Nervous System.
Contains all of the neurons/nerves outside of the CNS. Carries information to the spinal cord, and then from the spinal cord to connect the brain with voluntary muscles, sensory receptors, and involuntary muscles.
Somatic.
Voluntary skeletal muscles.
Sensory and Motor neurons.
Sensory
Afferent, towards the CNS.
Motor
Efferent, away CNS.
Autonomic.
Involuntry.
Sympathetic and Parasympathetic.
Sympathetic.
Prepares the body for action, responding to a threat.
Flight or Fight.
eg. Dilated pupils, increased heart rate, bladder relaxes, digestion stops.
Parasympathetic
Homeostasis. A level of calm.
eg. Heart rate decreases, temperature decreases.
Fight or Flight
Response for survival when under threat.
Interneurons
Afferent and Efferent, in the CNS.
Effector.
Muscle - whatever is having the effect.
Receptor.
Detects the stimulus.
Spinal Reflex.
Involuntry, unconscious. Somatic.
Response to certain potentially damaging stimuli without the involvement of the brain. It is automatically reflected back from the spinal cord.
Dendrites
Receive messages from other cells - receptors, other neurons.
Receive information using receptor sites.
The information exits in the form of neurotransmitters which are chemicals.
Cell body (soma)
Converts the chemical neurotransmitter message to an electrical message known as an action potential.
Axon
Carries the action potential (electrical message).
Axon terminal
Receives electrical messages and releases stored neurotransmitter chemicals.
Types of neurochemicals
Neurotransmitters
Neuromodulators
Neurotransmitters
- used at a single synapse.
- ONE post-synaptic neuron responds.
Glutamate + GABA.
Neuromodulator
- at any multiple synapses.
- MANY post-synaptic neurons respond.
Dopamine + Serotonin.
Glutamate
Memory - Neurotransmitter (Excitatory)
Dopamine
Pleasure - Neuromodulator (Excitatory)
Serotonin
Mood - Neuromodulator (Inhibitory).
GABA
Calming - Neurotransmitter (Inhibitory)
Excitatory
Increased chance of action potential/release electrical impulse/fire.
Inhibitory
Decreased chance of action potential/release electrical impulse/fire.
Threshold
Excitatory: Once over the threshold, the post synaptic neuron has reached action potential.
Inhibitory: Decreases until resting.
Neurotransmitters’ effects on postsynaptic neuron….
Excitatory & Inhibitory.
Neuromodulators affect neurotransmitters in 2 ways…
- Changes responsiveness of receptor sites, enhancing the excitatory or inhibitory effects of a transmitter.
- Changes the release pattern of a neurotransmitter from the pre-synaptic neuron.
Neural plasticity
Changes to the neuron.
-Learning.
-Brain Damage.
-Less frequent use.
Sprouting
Neurons develop new branches on dendrites or axons. (due to damage)
- Dendrites become bushier when used more frequently.
- Axon terminal appendages increase in number.
Rerouting
-New connections between neurons.
-Injury and damage response.
Pruning.
Undamaged neurons forming new connections with one another.
Reduction in connections when stimulation of a synapse is repeatedly weakened over time.
Long-term potentiation. LTP
Strengthening of synapses, more neurotransmitters, and receptor sites increase OVER TIME.
Communication is strengthened because the neuron can reach the threshold more quickly.
More stimulation because a higher number of neurotransmitters and receptors are binding.
Long-term depression. LTD
Repeated, WEAKENED stimulation signals to the pre synaptic neuron, to reduce the number of neurotransmitters and to the post synaptic neuron to reduce the number of receptor sites OVER TIME.
Stress
An individual experiences in response to an event.
A psychobiological process.
Subjective.
Stress - Biological.
Involuntry - Fight or Flight.
Stress - Psychological.
Emotional + Cognitive.
2 different types of Stressors
Internal + External.
Internal Stressor
- Body (within)
eg. a memory.
External Stressor
- Outside of body.
eg. assignment.
Acute
Short term.
Occurs quickly
Fight/Flight - Sympathetic.
Freeze - Parasympathetic.
Adrenaline.
Chronic
Long term.
Builds up over time.
Ongoing, cumulative.
Cortisol - a stress hormone.
Eustress
a POSITIVE perception of a stressor.
Distress
a NEGATIVE perception of stress.
Role of Cortisol
- Released in Chronic Stress + FFF.
- Maintains arousal allowing the body to deal with stress for a longer period of time.
- Turns off unnecessary body systems at the time.
- Excessive Cortisol over a prolonged period of time inhibits the immune system.
Seyles General Adaption Syndrome (GAS)
Resistance to stress.
1. Alarm Reaction Stage.
2. Resistance Stage.
3. Exhaustion Stage.
Alarm Reaction Stage.
Consists of:
Shock and Countershock.
Shock (Alarm)
Parasympathetic - Freeze Response.
Shock (Alarm) symptoms/effects.
- Heart rate decreases.
- Temperature drops.
- Breathing rate decreases.
Preparing for Fight/Flight.
Countershock (Alarm)
Sympathetic - Fight/Flight.
Adrenaline and Noradrenaline Hormones.
Countershock (Alarm) symptoms/effects.
- Heart rate increases.
- Breathing rate increases.
- Temperature rises.
Acute response to deal with stressors.
Resistance Stage.
Release of cortisol, energies the body to resist stressors.
- As resistance continues cortisol suppresses the immune system.
Resistance Stage symptoms and effects.
- More energy; if stress is chronic; ongoing, cumulative and/or severe.
- As resistance continues, frequent infections can occur (eg. Colds).
Exhaustion stage.
Bodies resources are depleted.
Exhaustion stage symptoms/effects.
- Severe fatigue.
- Diabetes, type II –> lifestyle (increased chance).
- Severe weight loss/gain.
GAS Limitations.
- Research not conducted on humans.
- Does not account for individual differences and psychological factors.
GAS Strengths.
- Measures a predictable pattern that can be measured in individuals.
- If stress is not prolonged, stages are still experienced. Therefore tracks biological patterns in different types of stress.
- Greater the intensity of the stressor the greater the physiological response.
Lazarus + Folkman’s transactional model of stress and coping.
Stressor —-> Benign/Irrelevant
|
v
Stressful.
- Primary Appraisal -> unconscious evaluation.
Threat ( Future ).
Harm/Loss (Past)
Challenge ( Eustress ) -> benefit.
Secondary Appraisal -> Conscious decision.
“Are there sufficient recourses to cope?”
YES –> Reappraised as NOT stressful.
NO –> Distress is experienced.
Strategies to cope with stress.
- Approach + Avoidant
Approach Strategy.
A strategy that reduces/eliminates stress. It is a DIRECT strategy.
Avoidant Strategy.
Reduces the stress response, but the stressor is not affected.
An appropriate strategy if no way to directly combat the stressor.
It’s Maladaptive meaning it makes the stressor worse.
approach + avoidant example.
You have a psychology SAC, on Friday that you want to pass.
Approach: Revise in Advance.
Avoidant: Go out with friends to distract yourself. Procrastination.
Context-specific effectiveness
Selection of a coping strategy that is appropriate for the stressor. THE RIGHT ONE TO DEAL WITH THE STRESSOR.
Coping Flexibility.
Recognising that a coping strategy isn’t working, and changing the coping strategy so it does.
NOT THE RIGHT ONE ANYMORE - HAVING TO CHANGE.
Gut-Brain axis.
Gut to the brain.
Brain to the gut.
Enteric Nervous System
Nerve pathways within the GI ( gastro intestinal) track link to the brain.
Gut microbiota
all of the microorganisms that live in the gut
Gut microbiome
- Microbiota.
collective term for a population of microbiota in a defined environment (includes the genes of microbes)
Gut-Brain Axis (GBA)
the bidirectional connection between the gut and the brain through the enteric and central nervous systems
Vagus nerve
the longest cranial nerve that connects the gut and the brain, enabling them to communicate
Good for your gut health. :)
- Fermented food.
—> Miso Soup.
—> Kimchi.
Microbiota is good gut bacteria.
Bad for your gut health. :(
- Antibiotics.
- Poor food choices.
—> High-fat diets.
—> Sugar (high).
Good microbiota health controls some stress hormone levels.
Communicates with the brain via. the vagus nerve to control neurotransmitter release in the brain.
HPA axis
hypothalamic–pituitary–adrenal axis
difference and similarity between neurotransmitters and neuromodulators.
Difference: Neurotransmitters have an effect on one or two synapses, whilst neuromodulators have an effect on multiple synapses.
Similarity: Both must bind to a specific receptor site to have an effect.