gut-brain axis

Question 1

gut-brain axis (ANS)

Answer 1

bidirectional communication link between the CNS and ENS

direct and indirect between cognitive/emotional areas of brain and gut

ie when anxious, we may end up with an upset stomach due to the signals our brain sent to out gut

Question 2

vagus nerve

Answer 2

the longest cranial nerve that connects brain and gut –> enables communication

90% afferent, 10% efferent

Question 3

gut microbiota

Answer 3

all of the microorganisms that live in the gut

good, bad and silent (ineffective) bacteria/fungi/organism

Question 4

gut microbiome

Answer 4

a population of microbiota in a defined environment

diversity is important; diminishes with age

not fixed; composition can change with internal and external factors (diet, infection, disease, lifestyle choices)

Question 5

gut-brain axis communication

Answer 5

communication extends to
- ANS
- immune system
- endocrine system
- HPA axis

Question 6

enterotype

Answer 6

the unique combination of gut microbiota each person possesses

Question 7

criteria for optimal gut microbiome

Answer 7

• is different for each individual
• high levels of microbiota (no. and species)
• diversity
• stability
• resilience/resistance to disturbance (ie antibiotics/poor diet)

Question 8

GBA emerging research

Answer 8

• germ-free lab. animals (effects of antibiotics, probiotics)
• faecal transplants (changes to microbiome –> influence brain activity, such as reduced symptoms of depression in rats)
• human infants given antibiotics (to understand connection of gut and brain)

Question 9

gut dysbiosis

Answer 9

an unbalanced gut micriobiome (no. or type)

this unbalance affects other gut functions (ie digestive, hormonal, neurotransmitter production, HPA axis activation etc)

Question 10

neurotransmitter production in the gut

Answer 10

gut dysbiosis may lead to changes in neurotransmitter production (GABA, serotonin, dopamine)

this impairs everything else (immune, digestive, infections, digestive disorders, stress reactivity, heart disease, mood, sleep, cognitive function)
can cause mental health/neurological disorders (autism, Parkinsons, schizophrenia, depression, anxiety)

Question 11

effects of stress on the GBA

Answer 11

disturbs the balance of gut microbiota and microbiota influence susceptibility to stress
- phys. and psych. stress responses induced
- less stress resilient
- poor recovery from stress induced changes

ie) infants born to highly-stressed mothers during pregnancy tended to have higher levels of bad bacteria and less good bacteria. Also had significantly higher stress levels and stress-related GI problems

Question 12

effects of healthy GBA

Answer 12

method: faecal transplant or diet changes
- reduced phys. stress responses
- less -ve effects of stress (ie stress-related behaviour and HPA activation)

Question 13

effects of stress of GI tract function

Answer 13

• changes in blood flow
• gastric secretions
• gut motility
• increased visceral perception and intestional permeability

these changes contribute to the development of various GI disorders

Question 14

poor microbial balance on stress management

Answer 14

significant disturbance of the MB due to stress triggers reactions
- more vulnerable stress-related changes
- stress management issues
- increased susceptibility to stress-related disorders

Question 15

limitations of GBA research

Answer 15

• still emerging
• most research conducted on animals
• lack of research evidence with both healthy/unhealthy ppl (experimental studies and long-term studies)
• caution in overstating research evidence