ENERGY 1 Flashcards
whats the amount of heat energy needed to raise 1kg of water by 1°C
1kcal
what are the neural signals of energy /food input mediated by
meditated by vagus nerve
what some examples of neural signals of energy / food input
» Distension activates stretch receptors
» Chemical stimuli (partially digested proteins, caffeine, and rising pH)
what are nutrient signals of energy / food input mediated by
Mediated by blood levels of nutrients (glucose, amino acids, fatty acids)
what hormones inhibit hunger / induce satiety (short term regulation)
CCK and insulin
what hormones induce hunger (short term regulation)
gherkin, glucagon
whats leptin (hormone involved in long term regulation)
Hormone secreted by adipose cells in response to an increase in fat mass / total energy stores
what do rising levels of leptin suppress
release of neuropeptide Y (hypothalamic neurotransmitter that enhances appetite)
wat do rising levels of leptin stimulate
the expression of appetite suppressants
describe levels of leptin in obese people
higher
what does leptin protect against during times of nutritional depravation
weight loss
how much of energy is lost as heat
75%
are energy conversions inefficient
yes
what are some examples of things that result in energy lost as heat
» Formation and cleavage of ATP bonds for work
» Muscle contraction
» Friction from blood flow
why is the inefficient of energy conversion good
because it allows us to stay in homeostasis, which allows for cellular heat warms tissues and blood and keeps body temperature steady
what are the component of total metabolic rate
basal metabolic rate, physical activity, thermal effect of food
what is total metabolic rate
Total amount of heat produced by all chemical reactions and mechanical work of the body (both anabolic and catabolic)
whats the basal metabolic rate
“Energy cost of living”; energy body needs for most essential activities
is body surface area important for basal metabolic rate
yes
what impacts basal metabolic rate
age, gender, body temp, stress, thyroxine
how does thyroxine impact basal metabolic rate
hyperthyrodism = lose weight easily; hypothryodism = gain weight easily
what do E and Ne stimulat
fat catabolism