Lecture 10 Flashcards
When VO2 max increases, what type of substrate is used?
Intramuscular (triglycerides/glycogen)
What tissues can only use glucose as fuel
Brain and other CNS tissue
How does exercise increase the muscles’ blood glucose uptake
- Contraction changes metabolite levels
- Signalling molecules are activated releasing GLUT-4 transporters from vesicles
- GLUT-4 transporters go to membrane and accept glucose from blood, bring it into cell
Resting blood glucose concentration
0.9-1G / 100mL
Blood glucose levels during exercise
Levels rise, then plateaus as exercise goes on (doesn’t change much)
What substrates can contribute to gluconeogenesis by converting to glucose-6-phosphate?
-Pyruvate
-Lactate
-Glycerol
-Some amino acids
What must glycogen convert to before glucose
Glucose-6-phosphate
Lipid mobilization during exercise
- FFA released from triglycerides
- FFA transported by albumin into muscle
- FFA undergo beta oxidation in muscle converting to acetyl-CoA for krebs cycle
Insulin’s role
Insulin (Beta cells)
Lowers blood glucose by:
-Brings glucose into cells
-Increases glycogenesis in liver
-Decreases gluconeogenesis in liver
-Promotes triglyceride formation
Glucagon’s role
Glucagon (Alpha cells)
Increases blood glucose by:
-Increases glycogenolysis
-Increases gluconeogenesis
Type 1 vs Type 2 diabetes
Type 1 (born with) : No insulin produced
Type 2 (obtained): Reduced insulin production/effect
Insulin stimulated glucose uptake mechanism
Insulin binds receptors, causing GLUT-4 transporters to move to cell membrane and bring in glucose
Adrenal medulla role
Releases catecholamines (Epi/NE)
Epi/NE role in exercise
-Stimulate glycogenolysis/gluconeogenesis in liver/muscle
-Increases HR
-Epi stimulates lipolysis (shifts fuel from glucose to fat as exercise goes on)
