Fuel metabolism and diabetes mellitus Flashcards
What are the 2 key roles of whole body metabolism?
- Storage of nutrients/breakdown of stores when required
2. Maintenance of blood glucose - brain energy source
What are the 2 states of metabolism?
Fed - absorptive state - anabolic
Fasted - post absorptive state - catabolic
What are the percentages of total energy storage molecules and where are they stored? (3)
Carbs - 1% - liver, skeletal muscle
Lipids - 77% - adipose
Proteins - 22% - skeletal muscle
What is the energy balance equation?
Energy output = work performed + heat produced
What is a positive energy balance?
Energy input > energy output
What is a negative energy balance?
Energy input < energy output
What is the energy balance during the fed absorptive state? And what is the hormonal control?
Positive
Insulin - anabolic
What is the energy balance during the fasted post absorptive state? And what is the hormonal control?
Negative energy output
Glucagon - catabolic
How is insulin release regulated? (3)
- Glucose is absorbed into the islet of Langerhans
- It binds to the B cells via muscarinic receptors
- These stimulate secretions of insulin
What happens when there is an increase in glucose?
Liver, muscle and adipose tissue all increase glucose uptake
What is the result of insulin action?
Reduce blood glucose
What is the effect of insulin on glucose uptake?
Insulin allows GLUT-4 to intake glucose into cells
What stimulates and inhibits glucagon release? (2)
Stimulated by low blood glucose
Inhibited by high blood glucose
What are the main actions of glucagon? (4)
Raise blood glucose
Stimulate hepatic glycogenolysis
Stimulate hepatic gluconeogenesis
Stimulate lipolysis
What are the steps at high blood glucose? (3)
- B cells activated, a cells deactivated
- increase insulin, decreased glucagon
- Decrease in blood glucose
