4B The gut-brain axis

Question 1

Gut-brain axis

Answer 1

• the connection between the CNS and the ENS
• enables bidirectional communication between the brain and the gastrointestinal tract

Question 2

What is the enteric nervous system and what does it do

Answer 2

• nerve cells lining the gastrointestinal tract from the lower part of the oesophagus to the rectum
• controls the digestive system

Question 3

Enteric nervous system coordinates

Answer 3

• the rythmic muscle contractions that move along the digestice tract
• regulates gastric acid secretion
• changes in local blood flow
• releases gut hormones
• interacts with the immune system

Question 3

How does bidirectional communication occur between the CNS and the ENS happen

Answer 3

via the vagus nerve and gut microbiota

Question 4

Vagus nerve

Answer 4

a nerve that connects the brain (CNS) to organs within the ANS

connects them via nerve fibres that directly link organs
e,g
- the lungs
- heart
- oesophagus
- intestinal tract

Question 5

What does the Vagus nerve control

Answer 5

crucial bodily functions:
- mood
- immune response
- digestion
- heart rate

Question 6

Gut microbiota

Answer 6

the microbe population found in the gut (digestive system)

Question 7

What does gut microbiota do

Answer 7

digests the components of our food to provide their own nutrition while at the same time providing us with energy and nutrience

Question 8

How does stress affect gut microbiota and nervous system function

Answer 8

• stress causes changes in gut microbiota + deficiencies in certain bacteria which have been linked to anxiety and depression
• some increase anxiety-related behaviours
• stress exposure early in life or adulthood can change an organisms microbiota composition
• the types and variety of microbe populations can shape our stress responsiveness
• treatment with healthy microbiota can reduce anxiety-like behaviour and reduce stress responsiveness in humans and mice