3 - Regulating blood glucose

What receptor does glucagon function by and what does it do?

G protein coupled receptors and increases blood glucose levels

What cells secrete glucagon?

α islet of langerhans cells

What receptor does insulin function by and what does it do?

enzyme linked receptors and decreasesblood glucose levels

What cells secrete insulin?

β islet of langerhans cells

What is the funciton of pancreatic accini? (2 points)

exocrine tissue that secretes digestive enzymes which flow through the duodenum into a duct

• these enzymes produce calcium carbonate to maintain alkaline environment

What to delta islet of langerhans cells secrete and what is its purpose?

somatostatin which suppresses insulin and glucagon

What to PP islet of langerhans cells secrete and what is its purpose?

pancreatic polypeptides (leptin) which regulates widespread appetite control

What is normal blood glucose levels?

4-8 mmol/L of blood

State two effects of hyperglycaemia

• causes brain function impairment if sustained

• glucose can stick to lipids and proteins which cause kidney, nerve, and capillary damage

State one effect of hypoglycaemia

causes changes in osmolarity

Insulin and glucagon work…

antagonistically

List two ways in which β islet of langerhans cells measure blood glucose concentration

• K+ channels close when ATP is bound

• Voltage gated Ca2+ channels open when cell depolarises

How do cells sense and respond to glucose? (4 points)

• glucose is transported into cell via GLUT2 transporter

• glucokinase converts glucose to glucose 6 phosphate (decreases glucose concentration = more can enter & can be used in glycolysis)

• produced ATP binds to K+ channel so that they cant leave

• depolarisation opens Ca2+ channels, its increase resulting in exocytosis of insulin granules

How do liver / muscle cells respond to insulin?

1. insulin binds to tyrosine kinase receptor which initiates signal cascade

2. signal cascade results in exocytosis in GLUT4 receptors, inserting them into the membrane, facilitating glucose entry