w7 Flashcards
define metabolism
the chemical processes that occur in a living organism in order to maintain life
how much energy does the transfer of ATP–>ADP release
3.6 kcal/mol
how much energy does the brain use at rest
about 25% of the bodes energy, 600kcal
what molecules do the brain use
ketones and glucose
what do gluconeogenesis and ketogenesis ensure
ensure substrates are available for the brain during starvation
what does the body store energy as
triglyceride
what is triglyceride formed from
acetyl-coA
how can acetyl-coA be formed from
carbohydrate, protein or fat
what is a hormone
a chemical messenger that is released by one cell stat acts on other cells
what is the hormone that lowers glucose
insulin
how does insulin work
Glucose stimulates the synthesis, activation and release of insulin from pancreatic β cells
• Actions
– Suppresses hepatic gluconeogenesis
– Suppresses hepatic glycogenolysis
– Suppresses ketogenesis
– Promotes glucose utilisation
– Promotes glycogen production in the liver and skeletal muscles
– Promotes FFA synthesis and storage in adipocytes, inhibits lipolysis
– Inhibits glucagon production
– Promotes protein synthesis and
decreases proteolysis
what are the hormones that raise glucose
glucago, adrenalin and cortisol and growth hormone
how does glucagon work
• Released by the α cells in the pancreas as the inhibition by insulin is removed
• Acts on the liver
– Increases glycogenolysis – Increase gluconeogenesis
how does adrenalin (noradrenalin) work
• Stimulated by hypoglycaemia • Acts on the liver – Increases glycogenolysis – Increase gluconeogenesis – Inhibits insulin secretion (α receptors)
how does cortisol and growth hormone work
– Limits glucose utilisation
– Increase glucose synthesis
who discovered the use of insulin and how
Dr F. Banting and Mr C. Best, his medical student, discover insulin in dogs
• They ligated their pancreatic ducts and waited until the exocrine cells degenerate, then ground up the remaining pancreatic cells and injected this substance into dogs rendered diabetic via pancreatectomy
• This was a summer studentship - perhaps the best studenship ever!