Post-Absorptive Mechanisms, Macronutrient Inter-conversion & Energy Balance Flashcards
What is the glucose pathway?
Intestines - Liver - Muscle, Brain, RBC, Adipocytes
What happens to glucose in the liver?
Converted to glycogen (its storage form)
Insulin promotes uptake of glucose from bloodstream to cells and facilitates storage of glucose as glycogen
Glucose feeds into acetyl coA in Krebs cycle
What happens to glucose in muscles?
Glucose stored as glycogen in skeletal muscle
Insulin promotes uptake of glucose from bloodstream to muscles
What happens to glucose in brain?
Glucose goes from bloodstream straight into Krebs cycle
ATP produced from Krebs cycle
If blood sugar is too low it can cause neurological problems due to lack of glucose for brain
What happens to glucose in RBC’S?
Need a constant supply of glucose
Glucose converted to pyruvate
Pyruvate used as a source of energy as well as lactate
What happens to glucose in adipocytes?
Glucose is stored as triglycerides
Glucose can also be used to provide ATP
Insulin promotes conversion of glucose and uptake into cells
What happens to amino acids in the body?
Amino acids can form proteins
Can form other various compounds such as hormones, carrier proteins etc
Can feed into the Krebs cycle to provide energy in the form of ATP
What do triglycerides do in the body?
Triglycerides are bound together by proteins
insoluble in water
Join together with proteins
Transport in blood stream
Can form into VLDL or chylomicrons
Chylomicrons enter the lymphatic system
What happens to glucose during a short fast?
Glycogen can be broken down back into glucose
Liver releases glucose into blood stream
Glucagon promotes breakdown of glycogen into glucose
Glycogenolysis
What happens to glucose during a long fast?
Glycogen stores used up
Amino acids can be broken down from muscles
RBC can release lactate which can be used as energy
Triglycerides from adipocytes can be broken down to glycerol
Glyconeogenesis
What happens to fats during fasting?
Triglycerides broken down into glycerol
Glycerol goes to liver and can be used to make glucose
Can be broken down to fatty acids and used as energy source for kidneys and muscles
Fatty acids can be converted to ketones which can be used by muscles as a source of energy
Lipolysis
Glucagon promotes this
What happens to the body during prolonged fasting?
Fatty acids released from fat cells and can be used as a source of energy for muscles
Fatty acids can be converted to ketones - ketogenesis which occurs in the liver
Ketones released in bloodstream and can be used as an alternative source of energy for the brain
Brain uses ketones and not glucose so glucose is now available for RBC
What is cortisol?
Steroid hormone
Released by adrenal
What is somatostatin?
Released by pituitary gland
What does insulin promote?
Glycogen storage
Fat storage
Protein synthesis
