EDWARD'S LECTURE NOTES:
More notes at http://tanguay.info/learntracker
C O U R S E 
The Science of Gastronomy
Prof. Lam Lung Yeung, The Hong Kong University of Science and Technology
https://www.coursera.org/course/scigast
C O U R S E   L E C T U R E 
The Chemistry of Hunger: Glucose, Insulin, Leptin, Ghrelin
Notes taken on August 16, 2013 by Edward Tanguay
glucose
a kind of sugar (the suffix "-ose" denotes a sugar)
glucose levels have much to do with how we feel, e.g. if we are hungry
after a meal, you accumulate glucose in your blood
gradually the level of glucose in your blood declines
glucostats (glucose sensitive receptor cells) monitor the amount of glucose and signal when there is not enough
when you have low glucose levels, you feel weak, and often when you feel weak, you feel hungry as well
infusion of glucose to duodenum (first section of the small intestine) speeds up the sense of satiety
insulin
hormone
insulin, produced by the pancreas, causes cells in the liver, skeletal muscles, and fat tissue to absorb glucose from the blood in order to convert it to storage
low level of insulin = hunger
high level of insulin = satiety
leptin
protein hormone
made by fat cells, i.e. adipose tissues
plays a key role in regulating energy intake and expenditure, including appetite and hunger
acts on receptors in the hypothalamus of the brain, where it inhibits appetite
low leptin level = hunger
high leptin level = satiety
mice without leptin or leptin receptors become obese since it doesn't sense that it is full, so it keeps eating
ghrelin
amino acid and hormone
increased when energy is low
triggers the feeling of hunger
produced in the top part of the stomach
high ghrelin level = hunger
when you fast, you produce a high level of ghrelin
because there is a time delay, you should eat smaller meals more frequently