Hormones And The Regulation Of Blood Glucose Concentration Flashcards
What are all hormones:
Produced in glands, which secrete the hormone directly into the blood
Carried in the blood plasma to the cells in which they act- known as target cells- which have specific receptors in their cell surface membrane that are complimentary to a specific hormone
Are effective in very low concentrations, but often have widespread and long lasting effects
Describe the second messenger model
- Adrenaline binds to a transmembrane protein membrane within the cell surface membrane of a liver cell
- The binding of adrenaline causes the protein to change shape on the inside of the membrane
- This change of protein shape leads to the activation of the enzyme called adenyl Cyclase. The activated adenyl cyclase converts atp to cyclic AMP (cAMP)
- The cAMP acts as a second messenger that binds to a protein kinase enzyme, changing its shape and therefore activating it
- The active protein kinase enzyme catalyses the conversion of glycogen to glucose which moves out of the liver cell by facilitated diffusion and into the blood, through channel proteins
What do the cells of the islets of langerhans include
A cells - which are larger and produce the hormone glucagon
B cells - which are smaller and produce the hormone insulin
Where are the islets of langerhans
Pancreas
What 3 important processes take place in the liver
Glycogenesis
Glycogenolysis
Gluconeogenesis
What is glycogenesis
The conversion of glucose into glycogen. When blood glucose conc is higher than normal the liver removes glucose from the blood and converts it to glycogen
What is glycogenolysis
The breakdown of glycogen to glucose. When blood glucose conc is Lower than normal
What’s gluconeogenesis
The production of glucose from sources other then carbohydrate, such as glycerol or amino acids
What 3 places does blood glucose come from
Directly from the diet
From the hydrolysis in the small intestine of glycogen= glycogenolysis stored in the liver and muscle cells
From gluconeogenesis
What do the B cells do in the pancreas when they detect the stimulus of a rise in blood glucose concentration
They respond by secreting the hormone insulin directly into the blood plasma
What happens when insulin binds to a specific glyocprotein receptor
A change in the tertiary structure of the glucose transport proteins, causing them to change shape and open
An increase in the number of carrier proteins responsible for glucose transport in the cell surface membrane
Activation of the enzymes that convert glucose to glycogen and fat
In what ways is blood glucose concentration lowered
By increasing rate of absorption of glucose into the cells, especially muscle cells
By increasing the respiratory rate of cells, which therefore use up more glucose, thus increasing their uptake of glucose from the blood
By increasing the rate of conversion of glucose into glycogen in the cells of the liver and muscles
By increasing the rate of conversion of glucose to fat
What do a cells detect and then do
They detect a fall in blood glucose conc and respond by secreting the hormone glucagon directly into the blood plasma
What does glucagon do when it’s secreted into the blood plasma
Attaches to specific protein receptors on the cell surface membrane of liver cells
Activating enzymes that convert glycogen to glucose
Activating enzymes involved in the conversion of amino acids and glycerol into glucose
How does adrenaline raise blood glucose
Attaching to protein receptors on the cell surface membrane of target cells
Activating enzymes that causes the breakdown of glycogen to glucose in the liver
