GI 8 Flashcards
what does marijuana have to do with the munchies?
-marijuana usage often associated with a stimulation of appetite
-prescribed as a means to stimulate appetite in patients with chronic diseases associated with reduced appetite (cancer, aids)
-research in mice points to an enhanced sense of smell (eat more)
-evidence for indirect activation of NPY/AgRP neurons in ARC (CB1 receptor in LH)
what is our energy output and input?
how to we measure input?
heat released from burned food in measured
-one kilocalorie is the amount of heat needed to raise the temperature of 1 L of water by 1 degree celsius
-slight over estimation because we do not completely digest and absorb most foods
how do we measure output?
-direct calorimetry (most accurate)
what is basal metabolic rate (BMR)?
-an individuals lowest metabolic rate (sleeping)
-usually measured at resting metabolic rate (RMR)
what are the factors affecting overall metabolic rate?
- age and sex: male 1kcal/hour per kg of body mass, females 0.9kcal/hour/kg
- amount of lean muscle mass
- activity level-metabolic activity about BMR
- diet, diet induced thermogenesis: energic cost of food digestion and storage differs between different food components (lipids=low energy, protein=high energy)
- hormones: thyroid hormones considered most important determinant of BMR, influence oxygen consumption and heat production of most tissues in the body
- genetics
what is metabolism?
the sum of all chemical reactions in the body and fall in to one of three categories:
1. extract energy from nutrients
2. use energy for work (transport, mechanical, synthesis)
3. store excess energy for later use
-energy metabolism during fed and fasted state
what is the fed state graph?
fed state is mainly anabolic
GLYCOGEN AND PROTEIN STORAGE LIMITED, FAT STORAGE UNLIMITED
what do skeletal muscles do in the fed state?
skeletal muscle
-takes up glucose for energy usage and stores glucose as glycogen (70% of body storage)
-AA’s primarily taken up for natural protein turnover
what does the liver do when in the fed state?
-converts glucose to glycogen (24% of body stores)
-converts glucose to fatty acids (transported to adipocytes)
-AAs used for synthesis and converted to keto acids (energy or fatty acid synthesis)
what do adipocytes do when in the fed state?
-take up dietary triglycerides from chylomicrons
-excess glucose taken up and converted to triglycerides
-stores triglycerides synthesized in liver
where are the energy stores in a healthy individual?
-glycogen stores can sustain quiet activity for only a few hours
-proteins potentially for long periods of time but decrease protein levels eventually compromise cellular function
-fats for approximately two months
what is the graph of the fasted state?
-in between meals catabolism takes place to utilize stored energy
what does skeletal muscles do when in the fasted state?
-can convert glycogen to glucose-6-P (glycogenolysis) for its own use
-forms pyruvate and lactate
what does the liver do during the fasted state?
-glycogen can be converted to glucose (glycogenolysis) and transported throughout the body
-produces new glucose from pyruvate, lactate, glycerol and certain amino acids (glucogenesis)
-converts FA to ketone bodies for energy usage
what is the summary between the fed state and the fasted state?
what is the main regulator in the fed state?
how to beta cells respond to high glucose?
what is insulin’s cellular mechanism of action?
tyrosine kinase receptor
-insertion of glucose transporters
-increase or decrease metabolic enzyme activity
what is the regulator in the fasted state?
