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Regulation

gut-brain axis, a biodirectional primary types of feedback mechanisms:
communication system between the negative feedback and positive feedback.
gut and the brain that affects mental
health and stress response. Certain gut Positive feedback mechanism
bacteria synthesize neurotransmitters A positive feedback mechanism is a process
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such as serotonin, dopamine and in the body where the output of a system
gamma - aminobutyric acid (GABA), intensifies or amplifies the original stimulus,
which influence mood, cognition and leading to an increased response. It enhances
behaviour. and accelerates physiological processes
rather than stabilizing them. It is typically
(d) Synthesis of essential nutrients: Gut
microbes produces essential vitamins used when a rapid, self-perpetuating
such as vitamin K and certain vitamin response is necessary. Examples include:
B (B , B , B ).
12 7 4 (a) Childbirth process: Stretching of
uterine walls during delivery causes
Generally, a balanced gut microbiome contractions that further stretch the
promotes good health, while an imbalance walls. This stretching continues until
(dysbiosis) can lead to issues like digestive child birth. See Figure 5.2.
disorders, weakened immunity, and
metabolic diseases. Probiotics (good (b) Lactation process: The breast
bacteria), prebiotics (fiber that feeds feeding through sucking stimulates
good bacteria), fermented foods, reduced milk production which causes further
antibiotic use and managing stress, helps feeding. This will also continue until
to support and improve healthy microbiota the baby stops sucking.
population in the gut.
(c) Ovulation process: During ovulation,
the follicle releases oestrogen
Feedback mechanisms
hormone which stimulates the release
Task 5.3 of luteinizing hormone and follicle

Search from the library and internet stimulating hormone which in turn
sources the animations about feedback promote further follicular growth.
mechanisms. Watch the animations and (d) Blood clotting process: During
prepare a short summary. blood clotting, blood platelets release

clotting factors which cause more
A feedback mechanism is a biological platelets to aggregate at the site of
system that regulates internal conditions injury.
by responding to changes in the body’s
environment. It ensures stability
(homeostasis) or amplifies specific
physiological processes. There are two

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