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Slide 1

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Control of blood
glucose…read more

Slide 2

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Eating and exercise changes the concentration of
glucose in your blood:
All cells require a constant supply of energy to work, and so
blood glucose concentration needs to be carefully monitored.
The concentration of glucose in the blood is normally around
90mg per 100cm³ of blood, and is monitored by the pancreas
Blood glucose concentration rises after eating food
containing carbohydrates
Blood glucose concentration falls after exercise, because
more glucose is used in respiration to release energy…read more

Slide 3

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Beta cells secrete insulin into the blood
Alpha cells secrete glucagon into the blood
Both are secreted by
clusters of cells in the
pancreas called the islets
of Langerhans…read more

Slide 4

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Insulin LOWERS blood glucose concentration when its
too high
Insulin binds to specific receptors on the cell membranes of liver cells and
muscle cells. It increases the permeability of cell membranes to glucose, so
cells take up more glucose.
Insulin activates enzymes that convert excess glucose into glycogen. Cells are
able to store glycogen in their cytoplasm as an energy source. This process is
called glycogenesis.
Insulin also increases the rate of respiration of glucose. The higher the rate of
respiration, the greater the demand for glucose and so the greater the
decrease in blood glucose concentration.…read more

Slide 5

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Glucagon RAISES blood glucose concentration when it
gets too low
Glucagon binds to specific receptors on the cell membranes of liver cells
Glucagon activates enzymes that break glycogen into glucose. This process is
called glycogenolysis. This glucose is released into the bloodstream, increasing
the blood glucose concentration.
Glucagon can also promote the formation of glucose from non-carbohydrate
sources. Glucose can be formed from fatty acids and amino acids, and this
process is called gluconeogenesis.…read more

Slide 6

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Negative feedback mechanisms keep blood glucose
concentrations at the norm.…read more

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