UNIT 3 AOS1 Flashcards
3 main roles of the Nervous System
Receives
Processing
Response
Receives
Receives sensory stimuli
Eg. Heart rate
Process
Processing information, making sense or interpretation
Respond
Responding back to stimuli, physical action
Eg. Using skeletal muscles - internal muscles
Central Nervous System
- Brain
- Spinal cord (spinal reflex)
Peripheral Nervous System
All nerves besides brain and spinal cord
- Somatic and Autonomic
Somatic
- Voluntary motor movements (conscious)
- Sensory and motor neurons
Sensory
Afferent, towards CNS
Motor
Efferent, away CNS
Autonomic
- Involuntary (unconscious)
- Controls visceral muscles
Sympathetic Nervous System
Activated in stress response, responding to threat. Fight / flight
Eg. Heart, breathing increases, pupils dilate, bladder releases
Parasympathetic Nervous System
Restores Homeostasis (balance)
Eg. Decreases heart rate, digestion continues at normal rate
Fight / Flight / Freeze
Response of survival when under threat
Spinal Reflex
Unconscious, immediate response to protect the body from harm
Spinal Reflex 1.
Receptors - cells that detect a stimulus
Spinal Reflex 2.
Sensory neurons - carry stimulus to CNS (afferent)
Spinal Reflex 3.
Interneurons - in the spinal cord intercepts the message and initiate a motor response
Spinal Reflex 4.
Motor response - carry message to skeletal muscles (efferent)
Spinal Reflex 5.
Response - message received muscles move
Neurochemicals
- Neurotransmitters
- Neuromodulators
Neurotransmitter
- Used from single pre-synaptic neuron to single post-synaptic neuron
- Glutamate + Gaba
Neuromodulators
- Used at more than one post-synaptic neuron
- Dopamine + Serotonin
Excitatory
Increased chance of action potential
Inhibitory
Decreased chance of action potential
Glutamate
Memory - neurotransmitter (excitatory)
GABA
Calming - neurotransmitter (inhibitory)
Dopamine
Pleasure - neuromodulator (excitatory)
- Reward system
- Repetition of certain behaviours (links behaviour with reward)
Serotonin
Mood - neuromodulator (inhibitory)
Chemical Transmission 1.
Electrical impulse reaches axon terminal of the pre-synaptic neuron
Chemical Transmission 2.
Neurochemicals are released from vesicles into the synaptic gap
Chemical Transmission 3.
Neurochemicals bind to a receptors on the post-synaptic neuron IF the shape is complementary
Chemical Transmission 4.
If neurochemicals are glutamate the post-synaptic neuron is more likely to release an electrical impulse
If neurochemicals are GABA the post-synaptic neuron is less likely to fire
Threshold
Excitatory: Once over the threshold, the post synaptic neuron has reached action potential.
Inhibitory: Decreases until resting.
Difference between neuromodulators and neurotransmitters
Neurotransmitters have an effect on one or two synapses, whilst neuromodulators have an effect on multiple synapses.
Similarities between neuromodulators and neurotransmitters
Similarity: Both must bind to a specific receptor site to have an effect.
Synaptic plasticity (Neuronal plasticity)
Changes to synapses with an increased or decreased stimulation
Synaptogenesis (Sprouting)
After repeated use (practice) of neurons they develop new branches on dendrites
- More efficient communication
- Bushier dendrites
- Axon terminals grow more appendages
Rerouting
- New neural pathways since new synapses form
- Response to damage to neurons
Pruning
- Decreased number of synapses to conserve resources for sprouting of other neurons
- Weak simulation leads to pruning
Long Term Potentiation (LTP)
Strengthening of synapses, more neurotransmitters and receptor’s are increased.
Repeated use of neural pathway:
- Increase in neurotransmitters
- Increase in receptors numbers
Long Term Depression (LTD)
Weakening of stimulation signals of a synapse, therefore less efficient
- Pre-synaptic neuron reduce in neurotransmitters (glutamate)
- Post-synaptic neuron reduce in receptors
Stress
An individuals experience in response to an event
- Subjective
Stress - Biological (Physiological)
Involuntary, fight / flight response
Stress - Psychological
Emotional + cognitive (thoughts) changes
Internal stressor
- Body (within)
eg. thoughts, illness
External stressor
- Outside of body (anything environmental)
eg. assignments
Acute
- Short term
- Adrenaline can be beneficial
- Fight / Flight - Sympathetic
- Freeze - Parasympathetic
Chronic
- Long term
- Ongoing pressure
- Cortisol - a stress hormone
Eustress
A POSITIVE perception of a stressor
Distress
A NEGATIVE perception of a stressor
Role of Cortisol
- A stress hormone
- Released by adrenal glands when stressor becomes more chronic
- Immune system is suppressed
Seyles General Adaption Syndrome (GAS)
Resistance to stress:
1. Alarm reaction
2. Stage of resistance
3. Stage of exhaustion
Alarm Reaction
Shock and countershock
Shock (Alarm)
Parasympathetic freeze response
- Heart rate drops
- Temperature drops
- Breathing rate decreases
Countershock (Alarm)
Sympathetic fight / flight response
Adrenaline and noradrenaline hormones
- Heart rate increases
- Pupils dilate
- Breathing rate increases
Resistance stage
Release of cortisol, energises the body to resist stressors
- Cortisol suppresses the immune system
- More energy
- As resistance continues, frequent infections can occur (cold)
Exhaustion Stage
Bodies resources are depleted
- Serve fatigue
- Serve weight loss / gain
- Diseases and Diabetes
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 + avoidance
Approach
Direct approach
- Directly minimises stressor
Avoidance
Indirect approach
- Minimises the effects/symptoms produced by the stressor
- Stressor always still there
Maladaptive
Makes avoidance worse in the long run
Approach + Avoidant example
Sac coming up:
Approach - studying
Avoidant - procrastination
Context specific effectiveness
Appropriate for the unique demands of the stressor
Example:
Studying for an exam
Coping flexibility
Recognising that the coping strategy is no longer effective and change strategies
Example:
Not being able to study right before the exam, taking deep breaths instead
Gut Brain Axis
Gut to the brain
Brain to the gut
- The connection between the gut and the brain through the enteric and central nervous system
Vagus Nerve
Connects the gut and brain, goes both ways
Enteric Nervous System
Nerve pathways within the GI (Gastro intestinal) track link to brain
Microbiota
Lots of different species of bacteria
Gut Microbiota
All the microorganisms that live in the gut
Gut microbiome
Human digestive-tract associated with microbes 🦠
Good for gut health :)
Fermented food
- Miso soup
- Kimchi
Microbiota is good gut bacteria
Bad for gut health :(
Antibiotics
Poor food choices like sugar and high fat
Good microbiota health controls some stress hormone levels.
Communicates with the brain via. the vagus nerve to control neurotransmitter release in the brain.