Short term regulation of appetite and satiety
Satiety signals (Increased)
Orexiginic signal (Decreased)
High orexigin signal
More food
Ghrelin
Orexogenic signal
Released by cells in the stomach in response to emptying
Gastric distension and CCK
Happens at NTS and then PVN and ARC
Insulin and blood glucose levels
Low insulin/glusocse: more drive for food
Happens in cephalic and gastric phase
If you want food what neurons are activated
NPY, AgRP
WHAT INFLUENCES DIET
Hunger
Satiety
Social
energy output
Heat (50%)
Work(50%)
Energy output =
Work + Heat
Direct calorimetry
Most accurate
From sugars
Indirect Carolimetry
O2 Consumption or CO2 production
Basal metabolic rate (BMR)
An individuals Lowest metabolic rate
Usually measured as resting metabolic rate (RMR)
Factors that affect overall metabolic rate
- Age and Sex
- Amount of lean muscle mass
- Activity level - metabolic activity above BMR
- Diet
- Hormones
Metabolism
The sum of all chemical reactions in the body and fall in one of the 3 categories
3 categories of metabolism
- Extract energy from nutrients
- Use energy for work
- Store excess energy for later use
Fed state
Excess of nutrients
Anabolic
Is fasted state the body mainly uses
Fatty acids
Fat storage is
Unlimited
Most energy is stored in
Skeletal muscle
Increase in what increased feeding behaviour
Ghrelin
What drives the fed state
Insulin
What happens in the fed state
Anabolism
K and L cells increase
Increase parasympathetic activity
Increase amino acid uptake
Protein synthesis
Fatty acid and triglyceride synthesis
Glycogen synthesis
Fatty acid and triglyceride synthesis
Insulins cellular mechanism
- Insulin binds to tyrosine kinase receptor
- Receptor phosphorylates insulin receptor substrate
What drives fasted state
Glucagon
