4. The science of obesity Flashcards
(78 cards)
what are some key drivers that promote overconsumption of food?
The increased availability of processed, affordable and effectively marketed food, abundance of sugar-sweetened beverages,
economic growth, behavioural changes and rapid urbanization in lowand middle-income countries
what is the most important player in obesity?
brain
how does the hypothalamus act in obesity?
homeostatic area - role in energy homeostasis by regulating energy intake and expenditure
complex control of appetite
what is the hunger centre that controls feeding behaviours?
the arcuate nucleus of the hypothalamus
what are 2 sets of neuronal population that reside in the arcuate nucleus?
neurons co-expressing agouti-related protein (AgRP) and neuropeptide Y (NPY)
what activates AgRP/NPY
neurons in the arcuate nucleus?
hormonal and neural signals from the gut, adipose tissue, and the peripheral organs
if AgRP/NPY neurons in the arcuate nucleus get activated, what happens?
stimulate hunger sensation and trigger food-seeking behaviours
the activity of these AgRP/NPY neurons is rapidly reduced upon access to food - these neurons are primarily involved in food-seeking or the homeostatic control of appetite, but are less likely to normally drive xxx?
food consumption
how do these AgRP/NPY neurons mediate their downstream effects?
via the melanocortin-4 receptors located in the nearby paraventricular nucleus
The AgRP/NPY neurons project directly to the second set of neurons that co-expressing what?
pro-opiomelanocortin (POMC) and
cocaine- and amphetamine-regulated transcript (CART)
what do pro-opiomelanocortin (POMC) and
cocaine- and amphetamine-regulated transcript (CART)?
suppress food intake by firing through the downstream inhibitory Y1 and gamma-aminobutyric acid (GABA) receptors
The homeostatic control of appetite in the arcuate nucleus is influenced by a
number of factors including?
the nutritional status of the organism, nutrient
sensing and availability, taste, smell and food preferences.
what is hedonic eating?
neural systems that involve emotional, pleasurable and rewarding aspects of eating
Hedonic eating is based on the feelings of reward
and pleasure that are associated with …?
seeing, smelling or eating food
in hedonic eating, the signals are transmitted by which pathways?
dopaminergic, opioid and endocannabinoid pathways
what does dopamine signal in response to emotional triggers, such as sadness, or environmental triggers, such as the smell or sight of delicious food?
desire to eat
when are Opioid and endocannabinoid
signals released ?
when food is consumed, and are responsible for
the feeling of pleasure associated with eating
Some people living
with obesity may have a heightened anticipation (wanting) of the
pleasure of food driven by a dysregulation of which?
dopamine
what is dysfunctional and is downgraded compared to the anticipation, resulting in a need to overeat to achieve the level of the anticipation?
the pleasure of eating the food (liking)
what is the target for the treatment of obesity?
controlling dysregulation between wanting and liking of eating
where is a brain region that is tied to consummatory behaviours and mediates positive reinforcement?
lateral hypothalamus
Hedonic eating is also
controlled by which system?
corticolimbic system, which consists of cortical areas, basal ganglia, hippocampus and amygdala in the midbrain.
which is responsible for executive functioning and overriding primal behaviours driven by the mesolimbic system
cognitive lobe
Cognitive functioning works well under optimal conditions including.. which help to deal with adverse situations
rest, oxygen, decreased stress and supports
