Unit 3 AOS 1 Flashcards
main functions of the nervous system
1.Receive info (what we sense and feel)
2.Process info (what we think)
3.Coordinate a response to info (what we should do)
what is a neuron
Basic cell of the nervous system responsible for the reception and transmission of information throughout the nervous system
types of neurons and their definition
Motor neurons- take infofrom CNS to senses
Sensory neurons- take info from the senses to CNS
Interneurons(AKA relay/connectorneuron)- only in the CNS and allow neurons to communicate to each other E.g. motor and sensory neurons
3.
what is the central nervous system and its main function
is made up of the brain and the spinal cord.
Main function: to process info received from the body’s internal & external environments and to activate appropriate responses
what is the Peripheral Nervous System (PNS)
The entire network of nerves located outside the CNS that transmits sensory info to and motor info from the CNS
The spinal cord connects the brain to the PNS
Somatic Nervous System (SNS)
Controls skeletal muscle activity via connecting skeletal muscles to the CNS
Sensory information: afferent (incoming information)
Motor information: efferent (outgoing information)
Controls voluntary movement
Autonomic Nervous System (ANS)
Responsible for the automatic processes that keep your body alive (e.g. breathing, heart beat &digestion) and actively involved in reaction to extreme emotions, such as fear, anger or nervousness.
Involuntary and self regulating
Keeps us alive: automatically!
division of the ans The sympathetic nervous system:
arouses the body when we experience an extreme emotion or a threat to enhance survival through an immediate response
- Fight or Flight or Freeze response
division of the ans The parasympathetic nervous system
Maintains and regulates homeostasis as well as calms or restores the body to its normal state of functioning after an extreme emotion or threat subsides
Rest and Digest
Works slower than the sympathetic NS
division of the ans The enteric nervous system
embedded within the walls of the gastrointestinal (digestive) tract and dedicated to its functioning
Conscious response:
A reaction to a sensory stimulus that involves awareness; compared with unconscious response.
Voluntary, intentional, goal-directed, largely controllable
Unconscious response:
A reaction to a sensory stimulus that does not involve awareness; compared with conscious response.
Involuntary, unintentional, automatic
Spinal Reflexes
An unconscious, involuntary response to certain stimuli, initiated within the spinal cord and controlled solely by neural circuits; also called reflex arc
Neurotransmitter:
A chemical substance produced by a neuron* that carries a message to other neurons or cells in muscles, organs or other tissue
Neural Synapse:
The site of communication between adjacent neurons
Synaptic gap:
The tiny space between the axon terminal of a presynaptic neuron and the dendrite of a postsynaptic neuron.
Role of neurotransmitters
Excitatory effectwhich stimulate or activate postsynaptic neurons to perform their functions
Inhibitory effectwhich block or prevent postsynaptic neurons from firing.
Glutamate (Glu):
The primary excitatory neurotransmitter for information transmission throughout the brain; plays crucial roles in the growth and strengthening of synaptic connections during learning and memory formation.
Gamma-amino butyric acid (GABA):
is the primaryinhibitoryneurotransmitter in the CNS. It maintains neurotransmission at optimal levels by making postsynaptic (‘receiving’) neurons less likely to fire.
Neuromodulators:
a neurotransmitter that can influence the effects of other neurotransmitters; also calledmodulator neurotransmitter
dopamine
Dopamine is a neurotransmitter or neuromodulator with multiple functions depending on where it acts
- include roles in coordinating movement, learning and behaviours that are rewarding
serotonin
serotonin a neurotransmitter or neuromodulator with multiple functions depending on where it acts
- functions include emotional processing, mood, and sleep onset
what is the Effects on brain activity of dopamine
excitatory effect at one location or an inhibitory effect at another, depending on the type of receptors that are present.
what is the Effects on brain activity of seretonin
inhibitory effects
Synaptic plasticity:
The ability of a synapse to change over time through use or disuse.
- It is also the biological basis of learning and memory.
Donald Hebb theory
when neurotransmitter is repeatedly sent across the synaptic gap, presynaptic and postsynaptic neurons are repeatedly activated at the same time.
When a presynaptic and a postsynaptic neuron are active at the same time, this changes the structure or chemistry of the synapse, strengthening the connections between these two neurons at the synapse.
When the synaptic connection is strengthened, this makes them more likely to fire together again and to transmit their signals more forcibly and efficiently in the future.
three ways Changes in synaptic connections occur in what 3 ways?
Sprouting, rerouting, pruning
Sprouting:
new pathways form
Growth of nerve endings on axons or dendrites enables new links to be made
Rerouting:
pathways go around
Entirely new neural pathways are formed
Pruning:
Use it or lose it
Synapses not frequently used decay and disappear
Long term potentiation (LTP)
The long-lasting strengthening of synaptic connections, resulting in enhanced or more effective neurotransmission across the synapse.
Long term depression
The long-lasting decrease in the strength of synaptic connections and transmission and neuronal response
stress
a state of physiological and psychological arousal produced by internal or external stressors, that are perceived by the individual as challenging or exceeding their ability or resources to cope
Stressor:
any stimulus that produces stress.
Internal stressor:
originates within the individual
External stressor:
originates outside the individual from situations and events in the environment
Acute stress:
stress that produces a high level of arousal over a short period of time.
Chronic stress:
high level of arousal that persist over a long period of time and results in a number of physiological and psychological responses which may be short term or long lasting.
Two models for describing and explaining physiological responses to a stressor are:
fight–flight–freeze response
GeneralAdaptation Syndrome (GAS) model
Thefight–or-flight–or-freeze response
is an involuntary, physical response produced by the sympathetic NS to a sudden and immediate threat (or stressor) in readiness to:
fight— confront and fight off the threat
flight— escape by running away to safety
freeze— avoid detection by keeping still and silent
fight or flight reactions
Part 1: Energise. The brain–body pathway that activates fight–flight is called the sympathetic adreno-medullary system (SAM). Very fast!
Part 2: Maintain. The HPA axis is activated if a stressor persists, resulting in the release of cortisol. Slower to start, longer lasting
freze reactions
Reaction that results in an organism being in a physiological state involving high arousal of the sympathetic and parasympathetic systems, resulting in a condition characterised by both energy conservation and a mobilised state ready for action.
Cortisol
A hormone secreted from the adrenal cortex to primarily energise the body in response to a stressor (involved in both acute & chronic stress)
Cortisol and chronic stress
Prolonged high-level cortisol can cause a rage of physiological issues as shown, as well as
Reduced cognitive performance (issues with learning and memory)
Increased susceptibility to and exacerbation of symptoms of mental disorders
Gut-brain axis (GBA)
The gut-brain axis is a bidirectional (two way) , multifaceted communication link between the CNS and ENS.
It involves indirect and direct pathways b/w cognitive and emotional areas in the brain with the gut
Structures of the GBA
CNS: Brain and spinal cord
Peripheral – Autonomic NS: Sympathetic, parasympathetic and Enteric nervous systems
Vagus nerve (links brain to gut)
Hypothalamic-pituitary-adrenal (HPA) axis
Vagus nerve
The vagus nerve regulates and communicates with the enteric nervous system and facilitates the bidirectional communication of the GBA
The vagus nerve is part of the parasympathetic nervous system and controls rest and digest functions
Gut microbiota
Microorganisms (bacteria, viruses and fungi) present in the digestive tract
Microbiome
is the total population of microbiota
Healthy gut microbiome:
high number of diverse species that are stable and resistant to significant changes over time. Helps the individual cope with stress
Microbiota purpose
Digest food
Produce and release neurotransmitters:
GABA
Serotonin (modulator)
Dopamine (modulator)
Improving the microbiome
Probiotic therapy (‘good’ strains of bacteria) e.g yakult
Faecal transplants
Exercise
Diet (whole fibrous foods, fermented foods and nutritional fats e.g. fish and nuts)
