Control Of Blood-glucose Concentration Flashcards
Blood glucose conc. is monitored by cells in the …….. …. ………., which are found in the ………..
Cells in the islets of Langerhans, which are found in the pancreas
Alpha cells secrete _____
Beta cells secrete _____
Alpha = Glucagon Beta = Insulin
How doers insulin lower blood-glucose concentration when its too high? (5 steps)
1) Insulin binds to specific receptors on the cell membranes of liver and muscle cells
2) This triggers the movement of GLUT4 receptors from vesicles in the cytoplasm to the membrane. Glucose can then diffuse via facilitated diffusion into the cell, through the GLUT4 proteins
3) Insulin also activates enzymes in liver and muscle cells that cause glycogenesis
4) The cells can store glycogen in their cytoplasm as an energy source
5) Insulin also increases the rate of respiration of glucose, especially in muscle cells.
Glycerol & amino acids —> Glucose
What term?
Gluconeogenesis
Glucose —> Glycogen
What term?
Glycogenesis
Glycogen —> Glucose
Glycogenolysis
Glycogenesis is activated by ______
Glycogenesis is inhibited by ______
Glycogenesis is activated by insulin
Glycogenesis is inhibited by adrenaline
Gluconeogenesis & glycogenolysis are activated by ______
Gluconeogenesis & glycogenolysis are activated by Glucagon
Glycogenolysis is activated by ______
Glycogenolysis is activated by adrenaline
How does glucagon raise blood-glucose concentration when it’s too low? (3 points)
1) Glucagon binds to specific receptors on cell membranes of liver cells
2) The enzymes that cause both glycogenolysis & gluconeogenesis are activated
3) Glucagon decreases the rate of respiration of glucose in cells
Which gland is adrenaline secreted from?
The adrenal glands
When is adrenaline secreted?
1) Blood-glucose concentration is low
2) Stressed
3) Exercising
When adrenaline binds to receptors in the cell membranes of liver cells, what occurs?
1) Activation of glycogenolysis
2) Inhibition of glycogenesis
3) Activates glucagon secretion & inhibits insulin secretion, which increases glucose concentration
The second messenger model applies to which hormones?
That I need to know about
Glucagon and adrenaline
Describe the second messenger model
1) The hormones bind to their complementary receptors
2) This activates an enzyme called ‘adenylate cyclase’
3) This converts ATP into cAMP. cAMP is a chemical signal called the ‘second messenger’
4) cAMP activates the enzyme protein kinase A
5) Protein Kinase A activates a ‘cascade’ of reactions that cause glycogenolysis
