National Geographic - USA (2020-01)

Scporindal^

GUT INSTINCTS

Our bodies host trillions of microbes, a collection of

bacteria, fungi, and protozoa that starts developing at

birth and is unique to each of us. These microorganisms

can communicate with our brains to regulate bodily

functions and even influence our mood, as well as

chronic conditions such as anxiety, through chemical

communication pathways known as the gut-brain axis.

The supports pathways of vagus nerve

the parasympathetic

nervous systemhelps to promote a , which

state of equilibriumin the body.

HOW THEY

COMMUNICATE

Chemmicrobes into nerves or the icals released by

bloodstreamareas that deal with m influence brain emory.

Chemcan also signal the limicals in the bloodstreambic

systemprocesses em—a brain area that otion and stress—

to change our moods.

Approximate number* INLATESTINRGE E

38 trillion

VIA BLOODSTREAM

AND NERVES

Sensory neurons receive chem-

ical signals fromand relay them up this pri- gut microbes

mgut and brain. The brain sends ary signaling path between

back signals that mfunction, such as temodify pering

an inflamso the gut will keep working matory response

even if a person is sick.

THROUGH THE

VAGUS NERVE

Mnicating with the brain and icrobes can bypass commu-

directly signal the enteric nervous system—a meshlike

network of neurons in the digestive tract, sometimes

called the second brain—to independently influence gut

movements and secretions.

USING THE

‘SECOND BRAIN’

*BASED ON A TYPICAL M ALE, 20-30 YEARS OLD AND WEIGHING 154 POUNDS
MDIGESTIVE DISEASES; STEPHEN COLLINS, MONICA SERRANO, NGM STAFF; MESA SCHUMCMASTER UNIVERSITYACHER. ART BY INTERVOKE. SOURCES: EMERAN A. MAYER, UCL

THE MICROBES WITHIN