Metabolism Flashcards
Where does glucose get absorbed and then travel to?
Small intestine, the liver
What produces insulin?
Pancreas
What does insulin do?
Promotes conversion of glucose to glycogen for storage
What happens with excess glucose?
Goes into Krebs cycle, extra acetyl-coA, conversion to triglycerides, then becomes VLDL (very low density lipids)
In muscles, glucose is stored as
Glycogen
Glucose in the brain…
Used in respiration to produce ATP (via Kreb’s cycle)
Red blood cells need constant supply of glucose because
They don’t have mitochondria to maximise space for nucleus.
Therefore, anaerobic respiration, produce lactate and pyruvate
Glucose in Adipocytes
insulin promotes uptake of glucose, then conversion of glucose to triglycerides.
What are amino acids used for?
Proteins, various compounds (eg. hormones), used in Kreb’s cycle to produce ATP.
What are the fat carrying microns called and where do they travel?
Chylomicrons, travels in lymphatic system.
Made of triglycerides and proteins.
What happens during a short fast?
Liver releases glucose into bloodstream (from glycogen storage). Glucagon promotes this conversion.
Supplies brain and the red blood cells (need constant supply as don’t store glucose).
Process called glycogenolysis.
What happens during a long fast? (days)
Glycogen stores used up, amino acids from muscles broken down, red blood cells release lactate and adipocytes produce glycerol. Go to liver, creates more glucose.
Process called gluconeogenesis.
Fats during fasts
Triglycerides broken down to glycerol, travels to liver, used to make glucose.
Also broken down to fatty acids, energy source for kidneys and muscles.
Also produces ketones in liver which can be used in muscles.
Glucagon promotes breakdown of triglycerides.
Prolonged fasting
No more amino acids.
Fatty acids from adipocytes converted to ketones.
Ketogenesis in liver. (decreased gluconeogenesis)
Ketones released to bloodstream. Alternative form of energy for brain.
Decreased use of glucose in brain so available glucose can be used in RBCs.
Substances which can be measured in bloodstream
Glucose, ketones, insulin, lactate, triglycerides.
