Principles: control of plasma glucose Flashcards
What is hypoglycaemia?
blood glucose <2.5 mmol/L
What cell types are found in the pancreas’ Islets of Langerhans? What do they secrete?
- alpha (glucagon)
- beta (insulin)
- delta (somatostatin)
What are the effects of insulin?
Anabolic (fed-state hormone):
Conversion of glucose into glycogen, fatty acids into triglycerides, amino acids into protein.
What are the effects of glucagon?
Catabolic (hungry-state hormone):
Conversion of glycgen into glucose and triglycerides into fatty acids.
Effects of sympathetic stimulation on insulin secretion by pancreatic iselets?
Inhibition of secretion
Effects of para-sympathetic stimulation on insulin secretion by pancreatic iselets?
Stimulation of secretion
What is the role of Incretins?
Enhancement of insulin secretion in response to glucose ingestion
3 known incretins?
CCK (cholecystokinin)
GLP-1 (glucagon-like intestinal peptide)
GIP (gastric inhibitory peptide)
What are the target tissues of insulin?
Liver
Skeletal muscle
Adipose tissues
What is the glucose transporter in muscle and adipose tissue regulated by insulin?
GLUT4
Why do diabetics suffer from ketoacidosis?
- Failure to utilise glucose (due to lack of insulin or loss of sensitivity to it) promotes metabolism of fatty acids for energy.
- Excess fatty acid metabolism generates acetyl CoA, which is converted to ketone bodies, which lover blood pH.
- This is compensated by hyperventilation.
What are the effects of glucagon on the liver?
Catabolic / hungry state hormone:
- glycogenolysis
- gluconeogenesis
- ketogenesis
What dietary component stimulates glucagon secretion?
Amino acids
-glucagon thus prevents hypoglycaemia following a protein-rich meal
What glucose-rising hormones are released from the adrenal glands in response to stress?
Adrenaline and Cortisol
