Describe the physiology and biochemistry of
fat,carbohydrate and proteinmetabolism
Carbohydrates are stored in liver and muscle as glucose polymers known as glycogen.
- The liver contains ~100g of glycogen
This can maintain plasma glucose for ~24 hours.
- Skeletal muscle contains ~200g of glycogen
This cannot be released into circulation, and is for use only by the muscle.
Production of glycogen is stimulated by insulin, which is released as plasma glucose levels rise following carbohydrate ingestion. When plasma glucose levels fall, the release of glucagon and adrenaline stimulates glycogenolysis.
- Describes the process of converting glucose into pyruvate
This is known as the Embden-Meyerhof pathway.
- Occurs in the cytoplasm
- Does not consume oxygen or produce carbon dioxide
- Produces 2 ATP
Glycolysis allows production of ATP in anaerobic conditions.
Gluconeogenesis is the production of glucose from other molecules. Gluconeogenesis:
- Requires ATP to perform
Some organs (heart, brain) rely on glucose for ATP
- Has many potential substrates:
- Amino acids
- Is stimulated by glucagon
- Is inhibited by biguanides (metformin)
- Chambers D, Huang C, Matthews G. Basic Physiology for Anaesthetists. Cambridge University Press. 2015.