Metabolic Changes in Health and Disease Flashcards
(53 cards)
Catabolism
Weight Loss
Anabolism
Weight Gain
How much body energy is lost as heat ?
60%
What does chronic, low-grade systemic inflammation cause ?
As a result of obesity :
Increases the risk of cancer, cardiovascular disease, osteoarthritis and other diseases.
What does obesity cause ?
Increases risk of developing metabolic syndrome and type 2 diabetes.
What controls appetitie enhancement / suppression?
Neuronal and hormonal factors regulate food intake
Describe the role of insulin in metabolism
Insulin :
Hypoglycaemic / Anabolic hormone
- Acts to decrease blood glucose / fuel storage
- Lock nutrients away in storage molecules
Describe the role of glucagon in metabolism
Glucagon :
Hyperglycaemic / Catabolic hormone
- Acts to increase blood glucose levels
- Mobilise energy stores
State the hyperglycaemic hormones
Glucagon
Adrenalin
Cortisol
Growth hormone
(not directly related to absorptive/postabsorptive events)
Give some functions of insulin
Stimulates :
- glucose uptake by cells
- amino acid uptake by cells
- glucose catabolism for energy
- lipogenesis & fat storage
- protein synthesis
Inhibits :
- gluconeogenesis
Give some functions of glucagon
Stimulates :
- glycogenolysis
- lipolysis and fat mobilisation
- gluconeogenesis
Function of metabolic homeostasis
Aims to ensure a constant supply of glucose for the brain (which uses 60% of all glucose produced)
Why does the brain require a constant supply of glucose ?
It is unable to store glycogen or utilise fatty acids (due to blood brain barrier).
State the key regulator of blood glucose
Liver
Buffering via :
- Glycogenesis
- Glycogenolysis
- Gluconeogenesis
State the normal blood glucose range
4-7 mmol/L
OR
70-110 mg/dL
How much energy does a 70kg person use per day ?
1600kcal/day
(up to 5000 active state)
How long do carbohydrate stores last ?
1 day or less - blood glucose will fall
Metabolic changes associated with short-term starvation
Proteins can yield glucose (deamination and gluconeogenesis), but need to be preserved as much as possible.
Muscle shifts to using fatty acids as primary fuel.
Triglycerides have limited ability to be converted to glucose.
Describe glucose sparing for the brain
Muscle shifts to using fatty acids as primary fuel.
Metabolic changes associated with long-term starvation
Ketone bodies build up
Over the 1st few days, the brain becomes more tolerant to lower glucose - uses ketone bodies
Over time the brain gradually increases the use of ketone bodies
The body preserves valuable protein reserves, as need for amino acids to fuel glucogenesis reduced (muscle preserved)
Describe a key feature of long term starvation
Ketone body build up
Brain increases use of ketone bodies (need for glucose reduced)
What is the cause of ketone body build up ?
A consequence of fatty acid breakdown of acetyl-CoA and reduced activity of the citric acid cycle.
State the metabolic changes in fasting
Brain :
- Can only use glucose and ketones for energy
Liver :
- glycogen becomes glucose
Adipose :
- Lipids become free fatty acids and glycerol that enter the blood.
Muscle :
- Glycogen can be used for energy.
- Muscle can use fatty acids
- Muscle protein broken down to amino acids to enter blood
Describe the function of the pancreas
Acts as both an endocrine and exocrine gland
