carbohydrate metabolism Flashcards
What are the main classifications of carbohydrates?
Monosaccharides, disaccharides, and polysaccharides.
How are carbohydrates digested in the small intestine?
Enzymes break down polysaccharides and disaccharides into monosaccharides, which are absorbed into the bloodstream.
How are monosaccharides transported across the intestinal wall?
By specific transport proteins via active transport and facilitated diffusion.
What happens to monosaccharides after absorption?
They are transported via the portal vein to the liver, where they are metabolized or sent into systemic circulation.
What triggers glycogenolysis, and what does it do?
Triggered during fasting; breaks down glycogen to release glucose.
What is glycogenesis, and where does it occur?
The synthesis of glycogen from glucose; occurs in the liver and muscles.
What is the role of glucose in metabolism?
It serves as the primary energy source for most tissues, especially the brain and red blood cells.
What is gluconeogenesis, and what are its main substrates?
The synthesis of glucose from non-carbohydrate sources like pyruvate, lactate, glycerol, and amino acids.
What are the consequences of high blood glucose levels (hyperglycemia)?
Osmotic diuresis, excessive thirst (polydipsia), microvascular damage, and glucose in urine.
What are the effects of low blood glucose levels (hypoglycemia)?
Loss of consciousness, hypoglycemic coma
How is blood glucose regulated in the fed state?
Insulin increases glucose uptake, glycogenesis, and synthesis of proteins and fatty acids.
How is blood glucose regulated in the fasted state?
Glucagon stimulates glycogenolysis and gluconeogenesis; glucose is spared for the brain and red blood cells.
What are the primary fates of glucose in the body?
Energy production, storage as glycogen, conversion to fatty acids, and synthesis of amino acids and nucleotides.
What is the role of glucagon in glucose metabolism?
It promotes glycogen breakdown and gluconeogenesis, especially during fasting.
What is the role of insulin in glucose metabolism?
It promotes glucose uptake, storage, and utilization as fuel, and suppresses gluconeogenesis.
