Energy homeostasis
- Created by: kpritchard16
- Created on: 21-12-18 21:19
View mindmap
- Energy homeostasis
- Bomb calorimeter
- a device for measuring the heat evolved in the combustion of a substance under constant-volume conditions
- Energy potentials
- Fat = 9.4kcal/g or 39.3kJ/g
- Protein = 5.3kcal/g or 22.4kJ/g
- CHO = 4.2kcal/g or 17.2kJ/g
- Energy balance
- energy expenditure
- the energy the body expends to maintain its basic functions and to perform all levels of movement and activity
- energy intake
- dependent on diet, regulated by hunger and calorie consumption
- the relationship between energy intake and energy expenditure
- Positive energy balance
- The amount of energy consumed in food exceeds the expenditure of energy, so excess is stored (adipose tissue)
- Negative energy balance
- the state in which energy intake is less than energy expended, resulting in weight loss
- Neutral energy balance
- The amount of energy consumed in food matches exactly the internal and external expenditure of energy
- energy expenditure
- AMP-activated protein kinase
- what does it stimulate
- hypothalamus, heart and skeletal muscles
- acts as key nutrient sensor and metabolic switch
- what does it inhibit
- pancreatic beta cells, liver and white adipose tissue
- heterotrimer complex comprising of catalytic alpha subunit with serine/threonine protein kinase domain and 2 regulatory subunits (beta and gamma)
- what does it stimulate
- Respiratory Quotient (RQ)
- RQ = VCO2/VO2
- normal = 0.8, range = 0.67-1.3
- Basal metabolic rate
- Conditions needed to measure
- 12hrs fast, good nights sleep, rest for at least 30mins before test, ambient temperature of around 25oC
- 40kcal/hr/m2 or 166kJ/hr/m2
- Influences
- body SA and composition, age, gender, temperature, endocrine and nervous effects
- How to measure
- Calculations
- (Revised) Harris-Benedict Equation - revised equation, more accurate
- Katch-McArdle Formula - uses lean mass
- (Original) Harris-Benedict Equation - height, weight and age
- Cunningham Formula - uses lean mass
- Mifflin St Jeor Equation - does not take into account body composition
- direct or indirect calorimetry, handheld device
- Calculations
- Conditions needed to measure
- Bomb calorimeter
Comments
No comments have yet been made