3.6.4.2 Control of blood glucose concentration Flashcards
1
Q
Describe the second messenger model (for glucagon or adrenaline)
A
- (hormone is 1st messanger)
- binds to specific complementary receptor on target cell (hormone receptor complex)
- this activates an intracellular enzyme (adenyl cyclate)
- which produces the second messenger, cAMP, from ATP
- this causes a series of redox reactions that result in the activation of a protein kinase that activates another enzyme
- which converts glycogen to glucose (glycogenolysis)
2
Q
What is glycogenolysis?
A
- Hydrolysis of glycogen into glucose
- in liver and muscles
3
Q
What is gluconeogenesis?
A
Creation of new glucose from amino acids and glycerol
4
Q
What is glycogenesis?
A
Creation of glycogen
5
Q
Where is insulin produced?
A
- Beta cells of islets of Langerhans
- in pancreas
6
Q
Where is glucagon produced?
A
- alpha cells of islets of Langerhans
- pancreas
7
Q
Describe type 1 diabetes
A
- pancreas doesn’t make enough insulin - insulin dependent
- starts in childhood
- develops quickly, obvious symptoms
8
Q
Describe type 2 diabetes
A
- insulin independent
- body cells not responsive ro insulin/insufficient insulin supply from pancreas
- starts later in life
- can be caused by poor diet
- develops slowly, less severe symptoms
9
Q
How can type 1 diabetes be treated?
A
- controlled by insulin injections
- control diet / sugar intake
- which are matched to glucose intake so blood glucose levels are monitored with biosensors
10
Q
How can type 2 diabetes be treated?
A
- regulating carbohydrates in diet and matching to excersise
- drugs which stimulate insulin production/ suplimented with insulin injections
- drugs that slow rate of blood glucose absorption from intestine
11
Q
Effects of insulin
A
- more insulin binds to receptors on target cells and activates enzymes
- inclusion of glucose transport channel proteins into membrane
- causes increased rate of glucose uptake by channel proteins
- increased cellular respiration rate
- glycogenesis (enzymes activated)
- increased conversion of glucose to glycogen
- increased conversion of glucose to fats (enzymes activated)
12
Q
Effects of glucagon
A
- attaches to receptors on target cells and activates enzymes
- glycogenolysis
- increased conversion of glycogen to glucose
- gluconeogenesis
- amino acids and glycerol converted to glucose
13
Q
Effects of adrenaline
A
- Activates liver enzymes
- glycogen converted to glucose
- enzymes inhibiting conversion of glucose to glycogen
14
Q
What is a hormone?
A
- chemical messenger
- secreted by glands
- carried in blood
- acts on target cells with complementary receptors
- widespread, long lasting effects
15
Q
Which hormones do and don’t use second messenger model?
A
- steroid hormones, lipid soluble, diffuse across phospholipid bilayer of cell surface membrane and enter cell, no need for 2nd messenger
- peptide hormones, water soluble, can’t diffuse across phospholipid bilayer of cell surface membrane, needs 2nd messenger
