Lecture 27: Power Sources and Metabolism Flashcards
What is glycogen used for?
Short term energy store
What happens to our glycogen overnight?
Our glycogen stores decrease, as they are used to generate glucose for the needs of the body
What is beta-oxidation?
Cyclic process, taking off two carbons each cycle
What does one cycle of beta -oxidation release?
One molecule of acetyl-CoA
What happens in the liver after a few days without food?
The liver starts to produce ketone bodies
Why do these ketone bodies form?
The TCA cycle is unable to further oxidize all the acetyl-CoA produced from fatty acids
What do ketone bodies supply?
A water soluble transportable form of energy as they are much more soluble than free fatty acids
What is ketoacidosis?
When large amounts of the ketone bodies acetotate and beta hydroxybutyrate are released from liver, the blood pH drops because they are acids
How is blood glucose levels maintained?
Through gluconoeogenesis but this requires pyruvate which cannot be produced from fatty acids
What do hormones do metabolically?
Integrate metabolism
What four major organisms are important to fuel metabolism?
Liver
Adipose tissue
Muscle
Brain
What is insulin?
An anabolic hormone of the well fed state
What does insulin do ?
Stimulates glycolysis
Stimulates lipogenesis by activating acetyl-CoA carboxylase
Insulin shuts down glucose- generating pathways and inhibits hormone-sensitive lipase in adipose tissue
Reduces blood glucose levels
How does insulin reduce blood glucose levels?
Glycogen synthesis
Lipogenesis
Glycolysis are all increased
Gluconeogensis
Glycogenolysis
Ketogenesis are all decresaed
What does glucagon do to blood levels?
Elevates blood levels- opposite effect of insulin
When and where is glucagon released?
When blood glucose levels drop and glucagon is released from the alpha- cell of the pancreas
What does glucagon do?
Acts only on the liver to stimulate glucogenesis, glycogenolysis , and shut down glycogen and lipid synthesis
When is adrenaline released?
During stress
Where is adrenaline released from?
The adrenal meduula
What does adrenaline produce?
a fight or flight response
What does adrenaline do?
Inhibits insulin secretion
What is cortisol?
A steroid hormone with longer catabolic effects
What produces cortisol?
Adrenal cortex
What are the effects of insulin after a meal?
Inhibits HSL- triglycerides not broken down to fatty acids
Insulin activates the glucose transporter- glucose is taken up by cells
Insulin activates acetyl-CoA - fatty acid synthesis increases
What is diabetes?
A disorder of reduced insulin production or reduced response to insulin
What is Type 1 diabetes?
Usually starts in childhood: caused by autoimmune destruction of beta-cells in the pancreas, so no insulin is produced
What is type 2 diabetes?
The most common, and occurs later in life.Insulin may be produced, but response to insulin is impaired-i.e insulin resistance
