Energy, Metabolism and Exercise Flashcards
In patients who have been in a starved or malnourished state, but then starts refeeding, the risk of refeeding syndrome is increased. What key energy molecule is important in refeeding syndrome?
- glucose
In patients who have been in a starved or malnourished state, but then starts refeeding, the risk of refeeding syndrome is increased. What key vitamin is important in refeeding syndrome?
- thiamine, also referred to as vitamine B1
In patients who have been in a starved or malnourished state, but then starts refeeding, the risk of refeeding syndrome is increased. What key electrolytes are important in refeeding syndrome?
- K+
- Na+
In patients who have been in a starved or malnourished state, but then starts refeeding, the risk of refeeding syndrome is increased. What key mineral is important in refeeding syndrome?
Mg+
In patients who have been in a starved or malnourished state, but then starts refeeding, phosphate is important. What syndrome is this important in?
- refeeding syndrome
In refeeding syndrome insulin binds with cells and glucose enters the cell. This can cause phosphate and K+ to flood into the cell causing what?
- hypokalaemia
- hypophosphatemia
In refeeding syndrome patients can experience high levels of oedema, what drives this?
- Na+ is pumped out of cells
- H2O follows the Na+
In refeeding syndrome patients can have low phosphate, K+, Mg+ and thiamine (B1) can do what to the heart?
- arrythmias
- heart failure
- cardiac arrest
In refeeding syndrome patients can have low phosphate, K+, Mg+ and thiamine (B1) can do what to the lungs?
- respiratory failure due to oedema
In refeeding syndrome patients can have low phosphate, what can this do to the neuromuscular system?
- weakness
- seizures
- coma
- confusion
- rhabdomyolysis
In refeeding syndrome patients can have low K+, what can this do to the neuromuscular system?
- paralysis (loss of muscle function)
In refeeding syndrome patients can have low Mg+, what can this do to the neuromuscular system?
- ataxia
- tremors
In refeeding syndrome patients can have low thiamine, what can this do to the neuromuscular system?
- Wernicke-Korsakoff syndrome
The rise of what hormone is responsible for Refeeding Syndrome in patients who start eating having been in the starved state?
- insulin
Which of the following electrolytes and vitamin abnormalities are not seen in Refeeding Syndrome?
1) Hypokalaemia
2) Hypophosphataemia
3) Hypomagnesaemia
4) Low thiamine
5) Hyperphosphataemia
- hyperphosphataemia
In the absorbative phase what happens to glucose once it is absorbed in the liver?
- stored as glycogen
- stored as triglycerides and amino acids
In the psot-absorbative phase how do we get our energy from the liver?
- Glycogenolysis = break down of glycogen to glucose
- Gluconeogenesis = breakdown triglycerides and amino to glucose
In the absorbative and post absorbative phase what happens to glucose once it is absorbed by non liver cells?
- absorbative phase = stored as glycogen
- post absorbative phase = glycogen turned to glucose for energy
In the absorbative and post absorbative phase what happens to fat once it is absorbed by non liver cells?
- absorbative phase = stored as triglycerides
- post absorbative phase = glycerol and fatty acids provide energy
In the absorbative and post absorbative phase what happens to protein once it is absorbed by non liver cells?
- absorbative phase = stored as proteins
- post absorbative phase = proteins turned to amino acids for energy
In the absorbative and post absorbative phase what are our many fules for energy?
- absorbative = glucose
- post absorbative phase = triglycerides
Human metabolism oscillates between the fed and fasting states. A ratio between which 2 hormones in the blood determines the metabolic switch between glucose and triglyceride metabolism in the fed and fasted states?
- molar ratio of insulin to glucagon in the blood
In the fed and fasted state (6-12 hours post meal) what are the insulin and glucagon levels?
- fed = HIGH insulin / LOW glucagon ratio
- fasted = LOW insulin / HIGH glucagon ratio
What is the definition of the fasted state?
- 6-12 hours post meal
Following food intake insulin release is stimulated from beta cells of the pancreas, which in turn inhibits glucagon (which normally is slowly secreted). What is the normal ratio of insulin to glucagon in the fed state?
- high insulin to glucagon ratio of 4 : 1
Following food intake insulin release is stimulated from beta cells of the pancreas, which in turn inhibits glucagon (which normally is slowly secreted). There is a high insuline:glucagon ratio of 4:1. This affects metabolims in what 3 tissues, and 1 tissue that remains unaffected?
- affected = liver, adipose tissue and muscle
- unaffected = brain
Once glucose has been absorbed by the liver in the fed state, what are the 3 main things that could happen to it?
1 - stored as glycogen
2 - enter glycolysis and produce energy
3 - enter glycolysis and produce fatty acids
Once glucose has been absorbed by the liver in the fed state, it can be stored as glycogen, enter glycolysis and produce energy or enter glycolysis and produce fatty acids. What happens to the fatty acids produced here?
- undergo lipogenesis
- fatty acid and triglyceride synthesis from glucose or other substrates
Once glucose has been absorbed by the liver in the fed state, it can be stored as glycogen, enter glycolysis and produce energy or enter glycolysis and produce fatty acids. Fatty acids then undergo lipogenesis, where fatty acid and triglyceride area synthesised from glucose or other substrates. Some triglycerides can be stored in the liver, but those that leave the liver, leave using what?
- very low density lipoproteins
- travel around body for energy or to be stored as adipose tissue
Once glycerol from triglycerides has been absorbed by the liver in the fed state, what happens to it?
- imported into lipogenesis
- used to make triglycerides
Once amino acids from triglycerides have been absorbed by the liver in the fed state, what happens to them?
- can enter the citric acid cycle and used to make energy
In the fed state blood glucose levels rise and are absorbed by skeletal muscle. Which GLUT transporter facilitates glucose uptake by skeletal muscle?
- GLUT-4
In the fed state blood glucose levels rise and are absorbed by skeletal muscle via the GLUT-4 receptors. What are the 2 things that can happen to glucose uptake by skeletal muscle?
1 - stored as muscle glycogen
2 - glycolysis and produce energy
In the fed state blood fatty acid levels rise and are absorbed by skeletal muscle. Whis is the 2 ways in which fatty acids can be absorbed?
- in the diet via chylomicrons
- via VLDL from the liver
In the fed state blood fatty acid levels rise and are absorbed by skeletal muscle. Fatty acids can be absorbed via the diet in chylomicrons and through VLDL from the liver. What then happens to the fatty acids once they enter the skeletal muscle cells?
- oxidised via β-oxidation (produce energy)
- acetyl CoA is produced that can enter the citric acid cycle and produce energy
In the fed state blood amino acid levels rise and are absorbed by skeletal muscle. What 2 things then happens to the amino acids once they enter the skeletal muscle cells?
1 - reformed into proteins for muscle growth and repair
2 - turned into acetyl CoA and enter citric acid cycle for energy
In the fed state blood glucose levels rise and are absorbed by adipose tissue via GLUT-4 receptors. What 2 things then happens to the glucose once they enter the adipose cells?
1 - enter glycolysis creating acetyl CoA that can then be used in lipogenesis to form triglycerides
2 - transformed into glucose-3-phosphate and can be used to form triglycerides
In the fed state blood fatty acid levels rise and are absorbed by adipose tissue. Whis is the 2 ways in which fatty acids can be absorbed?
- in the diet via chylomicrons
- via VLDL from the liver
If glycerol is released from skeletal muscle and adipose tissue, where will it then travel to?
- liver
- used in gluconeogenesis
In the fed state blood glucose levels rise and are absorbed by the brain. What 2 GLUT receptors are involved in glucose absorption in the brain?
- GLUT-1
- GLUT-3
In the fed state blood glucose levels rise and are absorbed by the brain via GLUT-1 and 3 receptors. What then happens to the glucose that has been absorbed by the brain?
- enters glycolysis for energy only
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is reduced from beta cells, and glucagon secretion from alpha cells of the pancreas is increased. What is the normal ratio of insulin to glucagon in the fasted state?
- liver switches from a glucose-utilizing to a glucose-producing organ
- low insulin to glucagon ration (ratio = 0.8 : 1)
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is released from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). What does this do to glycogen synthesis, glycogenolysis (breakdown of glycogen for energy) and gluconeogenesis?
- glycogen synthesis = reduced
- glycogenolysis = increased
- gluconeogenesis = initiated
Only when glycogen stored drop below what % does gluconeogenesis get turned on?
- 20%
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). GLUT-2 glucose receptors on liver have a low affinity of glucose and the liver no longer absorbs glucose but rather becomes what?
- producer of glucose
- exporter of glucose
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). GLUT-2 glucose receptors on liver have a low affinity of glucose and the liver no longer absorbs glucose and becomes and exporter of glucose. What 2 things are turned on in the liver cells only?
1 - glycogenolysis
2 - gluconeogenesis
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). What happens to protein in the liver?
- broken down to amino acids to fuel gluconeogenesis
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). What happens to triglycerides in the liver?
- triglycerides undergo lipolysis
- fatty acids from lipolysis used to produce energy via b-oxidation
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). What happens in adipose tissue to glucose?
- reduced glucose taken up by GLUT-4 receptors
- glycolysis is severely reduced
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). What happens in adipose tissue to triglycerides?
- neuroadrenalin stimulates B3 receptors on adipose tissue
- triglycerides broken down into fatty acids and glycerol
- fatty acids used as energy
- glycerol sent to liver for gluconeogenesis
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). In skeletal muscle the energy switches from glucose to what?
- B oxidation is switched on
- fatty acids are used as energy
- glycolysis is inhibited
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). In skeletal muscle what happens to proteins?
- broken down to amino acids
- carbon skeletons can be used for energy or exported to the liver in the form of alanine
In the fasting (post absorpative state), which is normally 6-12 hours following a meal, insulin secretion is release is decreased from beta cells, and glucagon secretion from alpha cells of the pancreas is increased, leaving a low insulin/high glucose ratio (0.8:1.0). Does this affect the brain?
- no
- GLUT-1 and 3 unaffected as have high glucose affinity
- brain cannot swithc to fatty acid for energy as they cannot pass the blood brain barrier
If we do not eat for over 12 hours this is classed as the starved state. What happens to the insulin and glucagon ratio here?
- chronic LOW insulin:HIGH glucagon
- 0.4:1 ratio
If we do not eat for over 12 hours this is classed as the starved state. There will be chronically LOW insulin:HIGH glucagon ratio (0.4:1). What happens to thyroid hormones and why is this important?
- thyroid hormones are decreased
- causes a decreases in metabolic rate
If we do not eat for over 12 hours this is classed as the starved state. There will be chronically LOW insulin:HIGH glucagon ratio (0.4:1). Thyroid hormones are decreased, which subsequently reduces metabolic rate. What becomes the primary energy source and what is produced?
- fatty acids are energy source
- ketones are produced