Control Of Blood Glucose Flashcards
Who discovered insulin?
Charles Best and Frederick Banting.
How was insulin discovered?
The pancreas was removed, which alleviated diabetic symptoms. They purified the extract which lead to the discovery of insulin.
What is the normal blood glucose level?
5mM.
What is the maximum blood glucose level?
Around 10mM.
What is the minimum blood glucose level?
2mM to 3mM.
What percentage of glucose-derived energy does the brain use?
20%.
What would occur if blood glucose went over the maximum limit?
There would be higher plasma osmolarity which would lead to dehydration of cells and glucose to be excreted in urine (osmotic diuresis).
What two hormones does the pancreas produce?
Insulin and glucagon.
Describe how insulin is produced.
It is synthesised as an inactive prohormone and is activated by proteolytic cleavage.
Insulin is secreted as an active hormone. What are the three peptide chains?
A, B and C.
How does the body respond to high levels of insulin?
Increase of glucose oxidation and glucose, fat and protein synthesis.
How does the body respond to high levels of glucagon?
Increases of glycogenolysis, gluconeogenesis and ketogenesis.
What are the four different types of stimulus for activating insulin secretion?
- Glucose in the plasma.
- Incretins being released in response to nutrient ingestion.
- Eating.
- Autonomic nervous system.
How does eating affect insulin secretion?
It actives the parasympathetic pathway, which stimulates insulin secretion.
How does stress affect insulin secretion?
It activates the sympathetic pathway, which inhibits insulin secretion.
What four effects does insulin have on the body?
- Increased glucose transport into cells.
- Increased use and storage of glucose.
- Increased use of amino acids.
4 Promotes fat synthesis (lipogenesis).
What does lipogenesis entail?
It inhibits beta-oxidation of lipids and promotes conversion of excess glucose and amino acids into lipids.
Insulin promotes glycogen, fat and protein synthesis at the expensive of glucose. Why?
Hyperglycemia.
What is the major secretory product of the alpha-cells of the pancreas?
Glucagon.
Where is glucagon stored?
Secretory vesicles.
Glucagon release is inhibited by what?
Glucose.
What is the stimuli for glucagon secretion?
Low glucose in plasma.
What state does insulin dominate in?
The fed state.
What state does glucagon dominate in?
The fasting state.
