Unit 3 AOS 1 Flashcards
What is the central nervous system made up of
The brain and spinal cord
What is the peripheral nervous system made up of
Everything else, eg. muscles, organs, glands
Central nervous system function
Receives sensory information from the peripheral nervous system and sends motor messages to the peripheral nervous system
Brain main functions
receives, processes and integrates info from the rest of the body and generates a response to it.
What is the spinal cord
A cable-like column of nerve fibres that extends from the base of the brain to the lower back and is encased in a series of bones called vertebrae
Spinal cord function
Sends sensory/afferent messages towards the brain and motor/efferent messages away from the brain
SAME
Sensory
Afferent
Motor
Efferent
Somatic nervous system
A network of neurons within the body that transmit information from receptor sites to the CNS and then carry information to the muscles to initiate voluntary movement
Autonomic nervous system
A network of neutrons that carry information between the CNS and the organs and glands to ensure they are regulated without conscious awareness
Two subdivisions of the peripheral nervous system
Somatic NS and autonomic NS
Three parts of the autonomic nervous system
Sympathetic NS, parasympathetic NS and enteric NS
Sympathetic NS
Prepares the body for action, activates fight or flight responses
Parasympathetic NS
Maintains the body in a state of homeostasis, returns the body to a state of calm after stress or heightened arousal
Sensory neuron
Transmits sensory information from the body to the brain via afferent pathways
Motor neuron
Transmits motor information from your brain to your body via efferent pathways
Interneuron
Transmits information between sensory and motor neurons
Which neurons does the spinal cord contain
Sensory neurons, motor neurons, interneurons
Spinal reflex
An unconscious, involuntary and automatically occurring response to certain stimuli without any involvement of the brain.
Enteric NS
Gut control, mesh of sensory and motor neurons lining the wall of the digestive organs. Receives and sends messages to the sympathetic and parasympathetic NS, controls many functions of the digestive system.
What part of the nervous system controls the spinal reflex
Somatic NS and CNS
Dendrites
an extension of a neuron that detects & receives info from other neurons
Receptor sites
these are locations on the end of the dendritic spines that receive the chemical form of the neural message (neurotransmitters) before it is sent to the soma (cell body)
Axons
a single, tubelike extension that transmits neural information to other neurons
Axon terminals
the location where the neurotransmitter is released into the synapse
Synaptic vesicle
the sacs in the Axon terminal that contain neurotransmitters.
Synaptic gap/cleft
the space between the neurons.
Synapse
The area that contains the presynaptic axon terminal + the synaptic gap + the post synaptic dendrite.
Lock
Receptor site on the dendrite of the post-synaptic neuron
Key
Neurotransmitters from the pre-synaptic neuron
Agonist
Activates receptor
Antagonist
Blocks receptor
Neurotransmitters
chemical messages passed across the synaptic gap by the pre-synaptic neuron to the post-synaptic neuron.
Inhibitory neurotransmitters
Chemical messages that make the post-synaptic neuron less likely to fire it’s action potential
Excitatory neurotransmitters
Chemical messages that make the post-synaptic neuron more likely to fire it’s action potential
GABA
he main inhibitory neurotransmitter. GABA slows neural transmission; thus, it has a calming effect, e.g. anti-anxiety medication
Glutamate
the main excitatory neurotransmitter. Glutamate aids in fast transmission of neural information; essential for memory formation
Neuromodulators
chemical messages released from a neuron that affect a large number of neurons at the same time.
e.g. dopamine or seratonin
Dopamine
A neuromodulator responsible for a variety of actions (excitatory effects) including smooth, coordinated movements and motivating behaviour in pursuit of a reward
Seratonin
an inhibitory neuromodulator that in produced within the CNS and intestines. serves as important function in regulating mood, sleep and responses to pain.
Synaptic plasticity
the brain’s ability to reorganise its neural pathways when damaged or when adapting to new experiences.
Synaptic plasticity structural changes
Sprouting and pruning
A change in the number of receptors on a post-synaptic neuron
Synaptic plasticity functional changes
Changes in the ability of the post-synaptic neuron to be excited by neurotransmitters
Changes to the amount of neurotransmitters released by the pre-synaptic neuron
LTP (long term potentiation)
a process where synaptic connections between neurons become stronger with frequent activation.
Sprouting
The growth of additional branches on axons or dendrites to enable new connections
Rerouting
Occurs when an undamaged neuron loses connection with a damaged neuron and forms a new connection with another undamaged neuron
LTD (long term depression)
a change to the connection between neurons that results in a long- lasting reduction in the strength of a neural response due to persistent weak stimulation
Synaptic pruning
The removal of unnecessary and unused neurons as a result of LTD in order to increase efficiency in the brain
Stress
the physiological and psychological response that a person experiences when confronted with a situation that is threatening or challenging.
Stressor
A person, object or event that is threatening or challenging
Internal stressors
Factors that originate from within a person e.g. low self-esteem
External stressors
Factors that originate outside the body e.g. moving to a new country
Distress
A negative psychological response to a stressor
Eustress
A positive psychological response to a stressor
Acute stress
The body’s immediate response to a perceived stressor
Chronic stress
The body’s response to a long-term or persistent stressor
Fight response
Confront the threat.
Activation of the sympathetic nervous system
Flight response
Flee from the source of danger.
Escaping is perceived as the safest option.
Activation of the sympathetic nervous system,
Freeze response
Immobility and shock in response to a threat.
Freezing may be the best guarantee of safety.
Brief activation of the parasympathetic NS. The sympathetic NS is also activated so the body is ready to spring into action.
What hormones do the adrenal glands release in the fight flight or freeze response
Adrenaline and nonadrenaline
Cortisol
The primary stress hormone, porduced by the adrenal glands and is released into the bloodstream.
Short term increase in cortisol
provides an immediate burst of energy to respond to a stressor.
Long term increase in cortisol
supresses the immune system, increases fatigue, sleep disturbances, emotional hypersensitivity, anxiety, and mild depression.
Hypothalamic-pituatary-adrenal axis
- Sympathetic NS
- Hypothalamus releases CRH
- Pituitary glands release ACTH
- Adrenal glands release cortisol into the bloodstream
Explanatory power
The ability of a model or theory to explain subject matter effectively
General adaptation syndrome (GAS) model
Describes the physiological changes that the body automatically goes through when it responds to stress
Alarm reaction
Body becomes aware of the stressor
Shock-Ability to deal with stressor is below normal level, body may display symptoms of injury
Countershock-Body rebounds, sympathetic NS activates, adrenaline and noradrenaline is released, resistance to stress increases
Resistance
Body’s resistance to stressor rises above normal, cortisol is released, individual appears as if everything is normal, all unnecessary physiological processes are shut down
Exhaustion
Resistance to stress is below average again, body’s resources are depleted, alarm reaction changes may appear again, resistance to disease is weak.
Limitation of GAS model
Was primarily based on research using animals, may have limited relevance to the human stress response
Strength of GAS model
Makes an important connection between stress and an increased risk of illness
What is the gut-brain axis
A bi-directional neural pathway that enables communication between bacteria in the GI tract and brain
The vagus nerve
Communicates between the gut and the brain, runs from the brain stem to the intestines
% vagus nerve fibres afferent vs efferent
90% afferent
10% efferent
From gut to brain
What sort of information is transmitted from the gut to the brain
-Hormones
-Neurotransmitters
-Pain
-Movement in muscles
-Tension in cells and muscles
What occurs when microbiota is disrupted
Increased levels of stress, anxiety, depression
Decreased memory and cognition
Microbiota
A diverse system of 100 trillion bacteria and other microorganisms that live in the GI tract.
