3.8 Gastrointestinal Physiology Energetics Flashcards
two general methods that nutrients energy is transferred to ATP?
anaerobic
aerobic
anaerobic mechanisms
- useful for short term
- only small amounts of energy made
- LACTIC ACID production
aerobic mechanisms
produce more ATP
*requires oxygen and more time
define efficiency of cell energy extraction
= total work done / total energy expenditure = % of energy actually used to do work
energy released per unit of ____ consumed
oxygen
repiratory quotient is ____ produced per unit of oxygen consumed
CO2
points of energetics is to determine?
main nutrient being metabolized by tissue
define metabolic rate
energy consumed per unit of body surface area per unit of time
*effected by age, body temp, specific dynamic action of food, hormones and physical activity
body temp is __% increase in metabolic rate per __degree F
6% per 1 degree
what is specific dynamis action of food?
- diet induced thermogenesis
- energy required for the process of digesting and assimilating food after a meal
- protein is greatest increase in MR
why does protein is greatest increase in metobolic rate?
takes more energy to digest and assimilate protein than CHO or fat (fat is least)
thyroxine
hormone that is most important in regulating metabolic rate (T3 more than T4)
do epi and nor stimulate metabolism?
yes
what are the sex hormones that stimulate metabolism?
testosterone > estrogen
*MR greater in males generally do to their larger amounts of testosterone
metabolic rate stongly affected by?
size of person and also by amount of physical movement
when is minimal metabolic rate?
during sleep (~65 cal/hr in ave. size male)
what is basal metabolic rate?
metabolic rate required for basic body functions at rest and awake
what are the conditions required to measure BMR?
1) comfortable room temp (70-80F)
2) at rest for at lest one hour
3) fasted for at least 12 hours
what is a direct measurement of basal metabolic rate?
direct calorimetry= measure heat given off with whole body calorimeter
what is a indirect measurement of basal metabolic rate?
indirect calorimetry (easier)
- measure oxygen uptake
- since oxygen is not stored and since its consumption generally keeps pace with immediate needs of the body, the amount of O2 consumed per unit of time is proportionate to the energy used
hypoerthyroidism
can inrease BMR to +100% of normal
hypothyroidism
can decrease BMR to 50% of normal (still have epi, NE, and sex hormones keeping BMR up)
