Post Absorptive Mechanisms And Energy Balance Flashcards
Glucose
Broken down in the intestine
Travels to the liver
From liver moves to muscles, brain, RBC and Adipocytes
Glucose in the liver
Stored in the liver as glycogen
Insulin is a hormone related by pancreas, promotes uptake off glucose by bloodstream into cells and so storage of glucose into liver
Glucose feeds into Acetyl CoA which feeds into Krebs cycle, ATP created
Acetyl CoA can form triglycerides
Glucose in muscle
Stored as glycogen
Insulin is used to
Glucose in the brain
Glucose is converted to Acetyl CoA which is used in the Krebs cycle to then be immediately converted to ATP for use
Lack of glucose in brain can lead to coma
Glucose in RBC
Don’t have mitochondria so require constant supply of glucose so glucose is converted into pyruvate which can be used as a source of energy and also converted to lactate also used for energy
No storage of energy and no Krebs cycle
Glucose in adipocytes
Glucose is stored in a form of triglycerides
Triglycerides stored in adipocytes
Insulin promotes process of glucose uptake and conversion in cells
Amino acids
Digestion of proteins to form amino acids
Absorbed into blood stream
Some form bodily proteins
Amino acids form various compounds- hormones, carrier proteins
Can be fed into Krebs cycle to produce energy in form of ATP
Triglycerides
Bound together with proteins and are insoluble in water so need protein to be transported in water of blood
One protein and lipid molecules- VLDL (very-low-density lipoprotein)
Protein and triglyceride can also form chlyomicrons which are used in lymphatic system
Network of lymph vessels which drain into bloodstream carry chylomicrons back into blood system
Summary of fed state
Fuels are oxidised to energy
Any excess is stored;
-Triglycerides in adipose tissue
-Glycogen in liver & muscle
Glucose- short fast
Glyoicgen is broken down back too gkuycose
So liver releases glucose into bloodstream and hormone glucagon promotes breakdown of glycogen into glucose
One of treatments for someone with low blood sugar levels is an injection of glucagon
Glucose used around body
Process is Called glycogenolysis
Glucose longer fast
Glycogen stored raw used up
If not replaced, amino acids can be broken down, red blood cells can release lactate for use as energy
Triglycerides from adipocytes can be broken to glycerol
All these sent to liver to make new glucose- gluconeogensis
Glucose then used by Brian and RBC
Fats during fasting
Triglycerides in adipocytes broken down into glycerol goes to liver used to make glucose to make ATP
Also broken down into fatty acids which can be used as energy source in kidneys and muscles- kidney use a lot and constant supply of energy
Fatty acids can be converted into ketones which are an alternative source of energy
Ketones Used as a source of energy
Process called lypolysis promoted by glucagon
Prolonged fasting
Starting to use up amino acids, fatty acids can be used as a source of energy in muscles as don’t want to break down majority of muscles to make amino acids
Fatty acids converted to ketones- ketogenesis
Occurs in liver and released into bloodstream
Can be used as alternative form of energy in the brain
Can not make new glucose so switches to source of ketones for energy
Brian uses ketones so doesn’t need glucose so glucose available for RBC as they need constant supply
Subatsnavce that can be measured
Glucose
Ketones
Insulin
Lactate
Triglycerides
Hormones regulating fuel metabolism
Insulin- anabolic building up molecules
Promotes glycogen storage, fat storage and protein synthesis
Glucagon- catabolic breaking molecules
-Promotes glycogenolysis, glucoeogenisis, ketogenesis
-(Pancreas has Endocrine and exocrine function)
Growth hormone somatostatin
Thyroxine
Adrenaline
Noradrenaline
Cortisol
