Metabolic response to sepsis, injury and starvation Flashcards
Simple starvation occurs 4-6 hours following meal, often described as phase 1 of starvation. Although lean tissue is conserved here, which of the following occurs?
1 - glycogenolysis and gluconeogenesis increases
2 - insulin resistance and gluconeogenesis
3 - proteolysis produces gluconeogenic amino acids
4 - ketones are produced from stored fat and glycogen stored are depleted
1 - glycogenolysis and gluconeogenesis increases
glycogenolysis = glycogen breakdown
gluconeogenesis = ATP from non-carbon sources
Phase 2 of starvation occurs 12-18 hours following meal. Here the body does what to provide energy?
1 - glycogenolysis and gluconeogenesis increases
2 - insulin resistance and gluconeogenesis
3 - proteolysis produces gluconeogenic amino acids
4 - ketones are produced from stored fat and glycogen stored are depleted
4 - ketones are produced from stored fat and glycogen stored are depleted
- fat becomes the main energy source
Mild ketosis is the physiological response to phase 2 fasting (aprox 12-18 hours since last meal). What is mild ketosis?
1 - insulin sensitivity is increased producing ketones
2 - glycogen is degraded producing ketones
3 - liver generates fat from ketone stores
4 - liver generates ketones from fat stores
4 - liver generates ketones from fat stores
- glucose is not essentially here as ketones are used from fat
Mild ketosis is the physiological response to phase 2 fasting (aprox 12-18 hours since last meal). This is called mild ketosis. What are the 3 main ketones?
1 - β-hydroxy butyrate, acetone and acetic acid
2 - β-hydroxy butyrate, acetone and acetoacetate
3 - butyric acid, acetone and acetoacetate
4 - acetic acid, β-hydroxy butyrate and acetoacetate
2 - β-hydroxy butyrate, acetone and acetoacetate
During phase 2 fasting (aprox 12-18 hours since last meal). The liver produces ketones from fat as an energy source, which is a physiological response called mild ketosis. This produces the 3 main ketones β-hydroxy butyrate, acetone and acetoacetate. During this time the bicarbonate (HCO3-) levels fall. Why is this?
1 - ketones damage kidneys and unable to retain HCO3-
2 - ketones cause metabolic alkalosis and HCO3- buffers
3 - ketones cause metabolic acidosis and HCO3- butters
3 - ketones cause metabolic acidosis and HCO3- butters
- normal HCO3- = 22-26mmol/L
- mild ketosis HCO3- = 7-8 mmol/L
During phase 2 fasting (aprox 12-18 hours since last meal). The liver produces ketones from fat as an energy source, which is a physiological response called mild ketosis. This produces the 3 main ketones β-hydroxy butyrate, acetone and acetoacetate. What would the ketone levels be after a 12hour fast?
1 - ~ 5 mmol/L
2 - ~ 8-10mmol/L
3 - ~ 1mmol/L
4 - ~ 20mmol/L
3 - ~ 1mmol/L
During phase 2 fasting (aprox 12-18 hours since last meal). The liver produces ketones from fat as an energy source, which is a physiological response called mild ketosis. This produces the 3 main ketones β-hydroxy butyrate, acetone and acetoacetate. The ketone levels after a 12hour fast would be ~ 1mmol/L. What might we see after a 20 day fast?
1 - ~ 5 mmol/L
2 - ~ 8-10mmol/L
3 - ~ 1mmol/L
4 - ~ 20mmol/L
2 - ~ 8-10mmol/L
Starvation phase 3 is the final phase of starvation. Which of the following occurs?
1 - glycogenolysis and gluconeogenesis increases
2 - insulin resistance and gluconeogenesis
3 - proteolysis produces gluconeogenic amino acids
4 - ketones are produced from stored fat and glycogen stored are depleted
3 - proteolysis produces gluconeogenic amino acids
Starvation phase 3 is the final phase of starvation where catabolic proteolysis occurs producing gluconeogenic amino acids. The muscles, liver and spleen are targeted before the brain and heart, but roughly what % of muscle, liver and spleen is lost during this phase?
1 - 10%
2 - 30%
3 - 50%
4 - 90%
3 - 50%
During phase 3 of starvation, catabolic weight loss, what happens to the bodies wound healing, immune response, GI integrity, mobility, mental state and energy?
- all decrease
Is ketosis always a bad thing?
- no
- good for T2DM, weight loss and epilepsy as examples
What happens to the glucose, insulin and glucagon during ketosis?
- low glucose = no glucose available, so fat is used
- low insulin = inhibited by glucagon
- high glucagon = inhibits insulin
What affect do ketones have on lipolysis?
- ketones inhibit lipolysis
- initially lipolysis increased to release FFA from TAG
- as ketones increase b-hydroxy butyrate provides a negative feedback inhibiting lipolysis
- this ensures the patient doesn’t go into ketoacidosis during starvation
What are the 2 main hormones that drive ketosis during starvation?
1 - T4 and cortisol
2 - epinephrine and T3
3 - IGF and cortisol
4 - epinephrine and cortisol
4 - epinephrine and cortisol
Starvation can cause a decrease in metabolic rate. Does the metabolic rate during an injury increase or decrease?
- increase
- body needs energy to repair itself
What happens to blood glucose utilisation and blood glucose levels during injury?
- both increase
- tissues need energy to repair
Starvation can cause an increase in gluconeogenesis. What happens to gluconeogenesis during injury?
- increased
- body tries to get as much energy as possible for repair
During starvation protein catabolism and urinary nitrogen (breakdown product of amino acid oxidation) are low, but what happens during injury?
- catabolism is increased
- urinary nitrogen is increased
- in starvation the body tries to preserve muscle mass, but in injury there is so much tissue damage