week 7 eating and obesity Flashcards
(21 cards)
what are 3 ways we store energy
85% fat in adipose tissue
14.5% in protein in muscle
0.5% glycogen in liver
what substance do you need to obtain glucose from glycogen in the body
insulin
what substance do you need to convert glucose to glycogen
glucagon
what is the first phase of metabolism
cephalic phase - preparation phase by set off from sight or expectations of food
second phase of metabolism
absorptive phase - the meeting of body’s immediate energy requirements
what are the levels of insulin and glucagon associated with phase one and two of metabolism
high insulin and low glucagon
what is phase 3 of metabolism
fasting phase
what are the levels of insulin and glucagon associated with phase 3 of metabolism
low insulin and high glucagon to promote conversion of fat to fatty acids which you can use as fuel
what secrets ghrelin
the stomach
when does levels of ghrelin increase
shortly before a meal and decreases after you eat
what is ghrelin
a peptide hormone - a potent stimulator of food intake
associated with ravenous hunger
what external factors starts a meal
learning eg pavlov
cafeteria diet - eating lots of different things makes you eat me (you dont satiate on food)
social factors - people eat more in groups
what stops a meal
adipose tissue which releases leptin
more adipose tissue/ higher weight means higher levels of leptin being released in the blood
stretch receptors in stomach
release of CCK, PYY (calorie dependent and reduces meal size)
what did kahler et al 1998 find about injecting leptin in mice
stops a meal
what does entry of food into the duodenum (intestine) stimulate
release of cholecystokinin
what does cholecystokinin (CCK) close
pyloric sphincter in stomach - making the stomach get full faster so you stop eating
what part in the brain responds to signals of hunger and satiation
arcuate nucleus - aggregation of neurons in the mediobasal hypothalamus which respond to ghrelin
it releases neuropeptide Y as a response to ghrelin which affects the lateral hypothalamus which releases MCH and orexin- leads to ravenous hunger and decreases metabolism
what does NPY stimulate the activity of
melanin-concentrating hormone and orexin produced but the lateral hypothalamus which stimulate hunger so preserve body’s energy stores
what does PYY and leptin inhibit
release of NPY in arcuate nucleus
the arcuate nucleus also releases CART &ALPHA-MSH which serve as anorexigens or appetite suppressing chemicals
this inhibits MCH and orexin in later hypothalamus
how does leptin exert some of its satiating effects
by binding with leptin receptors on neurons in the arcuate nucleus
what causes you to either store more energy as fat or increase metabolic rate?
uncoupling protein in muscles
increasing levels of UCP’s is associated with increasing metabolic rate, so less glucose left over to store as fat
