unit 3 aos 1 Flashcards
central nervous system
comprises of the brain and spinal cord
peripheral nervous system
entire network of nerves located outside the CNS
carried info to and from the CNS via somatic + autonomic
brain
an intricate network of cells that helps process info received through neural pathways from the body and helps direct actions in the body
neural pathways
a route based on interconnected neurons that form a communication network:
- within the brain
- between brain and nervous system
- between brain and body
spinal cord
long, thin, bundle of nerve tissue connecting the brain and rest of the body via the PNS
initiates spinal reflex w/o the brain
roles of the spinal cord
- receives sensory info from the body (via PNS) and sends this info to the brain for processing
- receives motor info from the brain and sends it to relevant parts of the body (via the PNS)
roles of the PNS
- carries info to the CNS from the body’s muscles, organs, glands, and sensory organs
- carries information from the CNS to the body’s muscles, organs, and glands
Somatic nervous system
connects the CNS to the body’s internal organs and glands, providing feedback to the brain about their activities
afferent info
sensory info coming to the CNS
efferent info
motor info leaving the CNS
autonomic nervous system
connects the CNS to the body’s internal organs and glands, providing feedback to the brain about their activities
visceral muscles
muscles involved in the activity of internal organs and glands
sympathetic nervous system
activates internal muscles, organs, and glands to prepare for vigorous activity to deal with a stressor, threat, or emergency
parasympathetic nervous system
calms or restores the body to its normal state of functioning after the need for sympathetic nervous system activation has passed
enteric nervous system
embedded within the walls of the gastrointestinal tract and dedicated to its functioning
link between sympathetic and parasympathetic
The sympathetic and parasympathetic systems counterbalance each other’s activities without conscious effort
one is dominant, there’s no on/off
gastrointestinal tract
the part of the digestive system that comprises the hollow organs that food and liquid travel through during digestion
(mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus, liver, pancreas, gall bladder)
roles of the enteric nervous system
- ENS and brain interact for gut movement (detect physiological condition of the GIT + provide outputs to control gut)
- nutrient management, regulating gastric acid
- interacting with parts of the immune and endocrine systems located in the gut
parts of the enteric nervous system
rectum, intestines, duodenum, stomach, eosophagus
liver, pancreas, gallbladder
conscious response
a reaction to a sensory stimulus that involves awareness
- voluntary and with some degree of control over it
unconscious response
a reaction to a sensory stimulus that does not involve awareness
- involuntary, automatic, we cannot ordinarily control its occurrence
spinal reflex
an unconscious, involuntary response to certain stimuli controlled solely by neural circuits in the spinal cord
spinal reflex
an unconscious, involuntary response to certain stimuli controlled solely by neural circuits in the spinal cord
why are spinal reflexes adaptive?
Spinal reflexes are considered adaptive as they save time in situations that may be very harmful to the organism.
neurotransmitters
a chemical substance produced by a neuron that carries a message to other neurons or cells in muscles, glands or other tissue. attaches itself to the receptor sites of post-synaptic neurons
synaptic gap
the tiny space between the axon terminal of a presynaptic neuron and the dendrite of a postsynaptic neuron
neural synapse + its components
the site where communication typically occurs between adjacent neurons
- synaptic gap
- terminal buttons of pre-synaptic neuron
- dendrites of post synaptic neuron
excitatory effect
when a neurotransmitter stimulates or activates a postsynaptic neuron to perform its functions
inhibitory effect
when a neurotransmitter blocks or prevents a postsynaptic neuron from firing and therefore performing its functions
reuptake
Neurotransmitter that does not bind to receptors in the postsynaptic neuron is absorbed back into the terminal buttons by the presynaptic neuron
difference between visceral muscles and skeletal muscles
skeletal muscles are inactive in the absence of motor messages from the brain whereas visceral muscles act independently of the brain
differences between somatic nervous system and autonomic nervous system
- ## somatic nervous system initiates skeletal muscle movement, autonomic nervous system regulates activity of visceral muscles
glutamate
main excitatory neurotransmitter in the CNS that enhances transmission by making post-synaptic neurons more likely to fire
role of glutamate
- learning and memory
- strengthening of synaptic connections
- enables synaptic plasticity
- thought and movement
GABA
Gamma amino buryic acid
main inhibitory neurotransmitter in the CNS making post synaptic neurons less likely to fire
role of GABA
- prevents seizures by inhibiting firing
- reduces anxiety
- prevents over excitation
- regulates post synaptic activation in pathways
neuromodulator
a neurotransmitter that can influence the effect of other neurotransmitters
dopamine
neurotransmitter/neuromodulator that’s primarily responsible for voluntary motor movement, pleasure, and reward-based learning
inhibitory or excitatory
dopamine pathways
originates from the mid-brain, substantia nigra, ventral tegmental area
role of dopamine
- coordinate voluntary movement
- motivates people
- addictive behaviour
- reward based learning
- transmits neural info for smooth muscle movement
serotonin
neurotransmitter/neuromodulator primarily responsible for mood regulation and sleep
inhibitory
serotonin pathways
originates in the raphe nuclei (brainstem)
role of serotonin
- regulates + stabilises mood
- regulating sleep/wake
- arousal, digestion, appetite
synaptic plasticity
the ability of synaptic connections to change over time in response to activity or response
role of neurons
transmit, receive, and process information in the human nervous system
mechanisms of synaptic plasticity
sprouting - creation of new extensions on a neuron –> new connections
pruning - elimination of weak or ineffective synaptic connections to accomodate for stronger synaptic connections
rerouting - ability of a neuron thats connected to a damaged neuron to create an alternative connection with an undamaged neuron
neural communication
occurs when neurons communicate by releasing neurochemicals into the synaptic gap
long term potentation
the long lasting strengthening of synaptic connections that are regularly stimulated. enhances transmission
long term depression
the long lasting weakening of synaptic connections that arent regularly stimulated. less responsive transmission
internal stressor
a stressor that originates within the individual
external stressor
a stressor that originates outside the individual
acute stress
stress that lasts for a relatively short time
positive + negative effects of acute stress
positive - releases adrenaline which helps perform tasks, enhances problem solving skills
negative - elevated BP, reduced motivation to persist a task
chronic stress
stress that continues for a long period of time. can seem delibitating and overwhelming
negative effects of chronic stress
increased cortisol weakens immune system and harms physically and psychologically
fight/flight/freeze
an involuntary response to a threatening, fearful, or otherwise stressful situation in readiness for fight/flight
all energy is directed from non-essential body systems to those that help with fight/flight
freeze reaction
occurs when we’re overwhelmed by the threat that’s there’s no chance of fight or flight occuring
involves energy conservation (para) and readiness for action (sympathetic)
tonic immobility
the initial frozen state of the body in a freeze reaction
adaptive
cortisol
a hormone secreted from the adrenal glands in response to a stressor
more long lasting
roles of cortisol
- increases energy supplies (blood sugar + metabolism)
- turns off body systems not immediately required
- blocks white cell activity to reduce inflammation
- retards tissue repair and slows wound healing
- weakens immune system
negative effects of long term cortisol
- impaired immune system
- build up of fat tissue
- hypertension, atherosclerosis, digestive problems, hyperglycemia, heart attack/stroke
- impaired memory
- PTSD, depression, anxiety
gut brain axis
a bidirectional communication link between the central and enteric nervous systems
gut microbiota and the brain communicate
gut microbiota
all the microorganisms present in the digestive tract
roles of the gut microbiota
- influence the production of serotonin and other neurotransmitters in the gut
- influences the supply of neurotransmitters
entrotype
refers to the unique combination of gut microbiota we possess
microbiome
collective term for a population of microbiota in and on the body. can be affected by internal and external factors
gut dysbiosis
an unbalanced gut microbiome in number or type of microbiota
link of gut and brain and stress
- stress leads to changes in blood flow, gastric secretions, intestinal permeability, gut mobility
- disruption in the gut affects mood, arousal, behaviour, decision-making, and problem solving
- disturbances in the gut influences production and activity of neurotransmitters, immune system impairment, digestive disorders, stress reactivity, cognitive functioning, neurological conditions, and mental health disorders
limitations of gut brain axis
- reseach done with animals
- lack of experimental research + long term studies
lazarus and folkman
proposes that stress involves an encounter between an individual and their environment, and that a stress response depends on a person’s appraisal of the stressor and their ability to cope with it
primary appraisal
an individual’s evaluation of the significance of a stressor that results in a decision that can be stressful, benign-positive, and irrelevant
secondary appraisal
an individual’s evaluation of their ability to control/overcome a stressful situation
types of stress lazarus and folkman
harm/loss - damage that’s alr happened
threat - damage that could happen
challenge - potential for personal growth
strengths of lazarus and folkman
- focuses on psychological aspects
- explains why people respond to the same stressor in different ways
- allows for stressors and circumstances to change
- views stress as an interaction with the environment
limitations of lazarus and folkman
- overlooks biological aspect of stress
- difficult to test through experimental design because it’s subjective
- primary + secondary appraisals are difficult to isolate
general adaptation syndrome
a three-stage physiological response to stress involving alarm reaction (shock/countershock), resistance and exhaustion
alarm reaction - shock
alarm reaction - countershock
resistance stage
Occurs when the individual is actively dealing with the stressor and resistance is at its highest
exhaustion stage
strengths of general adaptation syndrome
limitations of the general adaptation syndrome
coping
attempting to manage stress in an effective way
coping strategy
method used to manage stress
context specific effectiveness
when there is a match between the coping strategy used and the stressful situation
coping flexibility
the ability to effectively modify or adjust one’s coping strategies according to the demands of different stressors
approach coping strategy
an effort to cope with stress by confronting the stressor and dealing directly with it and its effects
generally more adaptive
avoidance coping strategy
an effort to cope with stress by evading the stressor and dealing indirectly with it and its effects
ganglia
neurons grouped together in clusters in the enteric nervous system
differences between neuromodulators and neurotransmitters
- neurotransmitters are more fast acting
- neuromodulators influence the effects of other neurotransmitters
- neuromodulators release chemical messages into broader areas but neurotransmitters release chemical messages into a single synapse
