Homeostasis Flashcards
When BGC increases above optimum level, what happens to the water potential of our blood?
Decreases
What happens when the water potential of our blood becomes lower than the water potential of our cells?
Water moves out of cells into the blood, and the cells shrink and die
What happens when our blood glucose concentration decreases?
Cells can’t carry out as much respiration
What happens when our blood glucose concentration increases?
The water potential of the blood decreases
What factors affect blood glucose concentration?
Food, exercise
What cells release insulin?
beta cells
What cells produce glucagon?
Alpha cells
Which organ detects changes in our blood glucose concentration?
Pancreas
What does the pancreas release if it detects and increase in BGC?
Insulin
What does the pancreas release if it detects a decrease in glucose?
Glucagon
Where are beta and alpha cells found?
Islet of Langerhans
what are Islets of Langerhans?
Hormone-producing cells found in the pancreas
What is one way insulin decreases our BGC?
It increases the number of glucose channel proteins in the cell membrane, so more glucose can enter the cells, which reduces the BGC
What is glycogenesis?
When glucose is converted to glycogen
What is glycogenolysis?
Conversion of glycogen to glucose
What is gluconeogenesis?
The conversion of non-carbohydrate molecules into glucose, eg glycerol/amino acids are converted into glucose
What processes does glucagon stimulate?
Glycogenolysis and gluconeogenesis
What is the role of adrenaline in BGC?
Binds to complementary receptors in liver cells and activates enzymes that catalyse glycogenolysis
Does adrenaline increase or decrease BGC?
Increase
What’s the first messenger in the second messenger model?
Adrenaline
What’s the second messenger?
Cyclic AMP
When adrenaline binds to a liver receptor, what does it activate?
Adenylate cyclase
What does Adenylate cyclase convert ATP to?
Cyclic AMP
What does cyclic AMP bind to?
Protein kinase
Explain the role of the second messenger model in glycogenolysis
First, glucagon or adrenaline activates the enzyme adenylate cyclase, which converts ATP into cyclic AMP.
Cyclic AMP then acts as a second messenger, and binds to the enzyme protein kinase, which activates it.
This enzymes catalyses glycogenolysis.
