Week 7- Neural control of energy balance Flashcards
Components of energy expensiture
OBLIGATORY ENERGY EXPENDITURE(BMR)
and
PHYSICAL ACTIVITY
Physical activity can be broken down into…
Exercise and NEAT
BMR is
the energy expended at rest, it is the energy required to maintain basic cell and organ function. ~70% of total daily expenditure
How are BMR, sex and lean mass all related?
BMR is correlated to lean body mass( the higher fat free mas one has the higher their BMR). Becuase men tend ot have higher lean msuckle mass they tend to have higher BMRs than women
How does BMR change with age?
once we hit around 40 we start to see changes in BMR(reduce) as our body composition starts to change( we become more predisposed to gaining adipose tissue)
What can prevent age related declines in BMR
Exercise to maintain lean body mass
is weight change in response to exercise genetically determined?
yes it is, when a tein study was found assessing weight change after bike exercise it found consistent results of weight change between the twins but variability across sets of teisn showing that genetic do play a role.
The benefits of exercise on metabolic health
improves lipid profile, reduces fasting glucose and insulin levels, improved insulin sens, reduced haptic fat accum, reduces BP, improved cardiac function.
How does weight gain relate to NEAT?
From twin studies, we cna see that the ability to defend against weight gain is genetically predetermined but more than this that NET generally undeprrins this. When we increases NEAT then the response to overfeeding is generally resistant.
Uncoupling
occurs in specialised mitochondria where H+ usually going through ARP synthase go through a UCP pore instead to cause a proton leak and produce heat.
This is called uncoupled repisration and is a way that cells dissipate energy diverting it away from cellular energy.
Physical challenges that increase adaptive thermogeneis are…
specialised cellualr heat production. occurs in reponse to environmental cues
WAT vs BAT characteristics
BAT si enriched in mitochondria, increased vasc supply, lots of small lipid droplets
The symp control of BAT
how WAT and BAT are derived
Rerecruitement of BAT
It was thought that after reaching adolescence that BAT stores reduced( as babies lose need after developing muscle which can shiver) but it has been found that once puberty is reached, with an increase inlean muscle mass, BAT is recruited and redistributed
How obesity affects BAT rerecuitment
We see decreased BAT activtiy and rerecuitment but it is unclear is this a cause of consequence of obesity
As we age, the prevalence and activation of BAT…
decreases. This is also correlated to increase BMI/adiposity, as this increases BAT activation decreases.
BAT activ is lower in indivs with T2DM or insulin resistance
How is BAT associated with insulin sensitvtiy
BAT is important for E expenditure, thus it can help clear gluocse and harmful TAGs and thus is associated with increased sensitivity
BAT and varying ambient temperatures
Higher ambient temps see lower BAT
is there sexual dimorphism in BAT acitvity?
yes, women have higher BAT activity
How is BAT a metabolic sink?
When acitvated there is increased glucose uptake and BAT triglyceride clearance. thus it is insoved in clearance of harmful triglycerides and in improved insulin sensitivity.
Lastly BAT is cardioprotective because of the secretion of BATokines
is UCP3 in skeletal muscle as eefective as UCP1?
no it is not, but the higher amounts of skeletal muscle offset this.
2 ways that skM can produce heat
UCP3 coupling and via calcium cycling
calcium cycling in skM
Browning and whitening of fat tissue
consequence of complete b-adrenorecptor loss
increased body weight
decreased energy expenditure ( both baseline and in response to cold)
no change in food intake but increase in body weight due to changes in energy expenditure
decreased expression of UCP1( cold intolerance)
