Gut-Brain axis

Question 1

the gut is called the 2nd brain because there is bi-directional
communication between
the gut and the ???

Answer 1

CNS/brain

Question 2

ANS comprises the sympathetic and
parasympathetic branches and is in control of unconscious stuff like:
???, ???, ???

Answer 2

• Breathing
  – Heartbeat
  – Digestion

Question 3

The vagus nerve is the 10th
cranial nerve or CN X and
interfaces with parasympathetic control of the heart, lungs and
???

Answer 3

digestive tract

Question 4

TRUE or FALSE: Vagus nerves are NEVER paired

Answer 4

False, they are often paired, even though they are referred to as one nerve

Question 5

the ??? nerve is a mixed nerve composed of 80% afferent and
20% efferent fibres.

Answer 5

vagus nerve

Question 6

Afferent is communication from gut to brain OR from brain to gut?

Answer 6

from gut to brain

Question 7

Efferent is communication from brain to gut OR from gut to brain?

Answer 7

from brain to gut

Question 8

the vagus nerve is able to sense the microbiota metabolites through its
afferents OR efferents? and to transfer this gut information to the CNS and then to generate an adapted and/or inappropriate response

Answer 8

afferents

Question 9

A cholinergic anti-inflammatory pathway has been described
through VN’s fibres, able to dampen peripheral inflammation and decrease intestinal permeability. This can or can’t impact microbiota?

Answer 9

can impact it == very
probably modulating microbiota composition.

Question 10

TRUE or FALSE: Stress inhibits the VN and damages the gastrointestinal tract and microbiota. It is involved in the pathophysiology of GI disorders such as IBS and IBD which are
both characterised by a dysbiosis

Answer 10

TRUE

Question 11

dysbiosis refers to a ??? or maladaptation on or inside the body, such as an impaired microbiota

Answer 11

microbial imbalance

Question 12

enteric (intestine) nervous system is largely responsible for gut functions such as
– Motility
– Control of ???

Answer 12

fluid movements

Question 13

The GI tract has the densest concentration of immune cells in the body and is in constant communication with ??? in the gut

Answer 13

microbes

Question 14

what serves to facilitate communication between the gut and immune system through the recognition of self and non-self antigens in order to prime the immune system to identify harmful pathogens?
Hint: goblet cells secreting…. Which interact with…

Answer 14

goblet cells secreting a mucous layer which interacts with host microbiome and an exchange of molecules through the mucous layer and epithelium occurs

Question 15

two best known Enteroendocrine cells
– Enteroendocrine L cells
– Enterochromaffin cells
have a long or short lifespan?

Answer 15

long lifespan

Question 16

Enteroendocrine L cells secrete glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in post-prandial state
– Obese people have low levels of GLP-1 and PYY, WHY?

Answer 16

because both GLP-1 & PYY can stimulate satiation and inhibit eating
(control food intake, body weight and metabolism)

Question 17

Enterochromaffin cells (ECs) produce the majority of serotonin (5-HT) from dietary tryptophan (amino acid)
– 5-HT mediates many GI functions including intestinal ???, ???, pain reception, and inflammatory responses

Answer 17

peristalsis, electrolytes excretion

Question 18

TRUE or FALSE: neurotransmitter Histamine is responsible for mediating host-microbe cross talk

Answer 18

TRUE

Question 19

gamma-aminobutyric acid (GABA) synthesised from glutamate (by host and gut bacteria) is the chief inhibitory neurotransmitter in the developmentally mature mammalian CNS. Its principal role is reducing ??? throughout the nervous system

Answer 19

neuronal excitability

Question 20

Deficits in bile acid levels have been associated with small intestine bacterial overgrowth, activation of inflammation, and subsequent
damage to the epithelium. WHY?

Answer 20

Bile acids help to limit the expansion of bacterial population in the GI tract. Bile acids can exert antimicrobial effects directly due to their membrane – solubilising properties

Question 21

what is the most examined gut
microbial-derived metabolites, of which 95% consist of acetate, propionate and butyrate

Answer 21

SCFA (short-chain fatty acids)

Question 22

TRUE or FALSE: Acetate is the only SCFA found in the brain. It promotes an expression profile of regulatory neuropeptides that favour appetite
suppression = less appetite –> less consumption of food

Answer 22

TRUE

Question 23

TRUE or FALSE: Vast majority bacteria is NOT in colon

Answer 23

False, it IS in colon