The regualtion of blood glucose

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The regulation of blood glucose
The pancreas
a small organ lying below the stomach: it has both endocrine and exocrine functions
Secretion of enzymes
majority of the cells in the pancreas manufacture and release digestive enzymes (exocrine
function of the pancreas)
the cells are found in small groups surrounding tiny tubules
The pancreatic duct is a tube that collects all the secretions from the exocrine cells in the
pancreas and carries the fluid to the small intestine
fluid contains the following enzyme:
Amylase: a carbohydrase
Trypsinogen: an inactive protease
The fluid also contains sodium hydrogencarbonate which makes it alkaline: this helps to neutralise
the contents of the digestive system which have just left the acidic environment of the stomach.
The islets of Langerhans are small patches of tissue in the pancreas that have an endocrine
They contain two types of cells alpha and beta cells.
Alpha cells manufacture and secrete the hormone glucagon
Beta cells manufacture and secrete the hormone insulin
The islets are well supplied with blood capillaries and these hormones are secreted directly into
the blood.
The control of blood glucose
the concentration of glucose is carefully regulated
alpha and beta cells in the islets of Langerhans monitor the concentration of blood glucose
normal blood glucose concentration is between 90 - 120 mg 100 cm-3 or 4 ­ 6 mmol dm-3.
if blood glucose concentration falls the alpha and beta cells detect the changes and respond by
releasing a hormone
If blood glucose concentration rises too high
high blood glucose concentration is detected by the cells
cells secrete insulin into the blood as a response
insulin detected by receptors on target cells (liver cells, muscle cells and other body cells)
insulin binding to the receptors activates adenyl cyclase inside each cell which converts ATP
into cAMP
cAMP activates a series of enzyme controlled reactions in the cell
More glucose channel are placed into the cell surface membrane
more glucose enters the cell
Glucose is converted to glycogen for storage (Glycogenesis)
More glucose is converted into fats
More glucose is used in respiration

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If blood glucose concentration drops too low
low blood glucose concentration is detected by cells
cells secrete the hormone glucagon as a response
glucagon is detected by receptors on target cells (liver cells)
effects of glucagon include:
Conversion of glycogen to glucose (glycogenolysis)
Use of more fatty acids in respiration
The production of glucose from the conversion of amino acid and fats (gluconeogenesis)…read more

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Regulation of insulin levels
The importance of regulating insulin levels
insulin brings about the effect that reduce the blood glucose concentration
if blood glucose concentration is too high it is important that the insulin is released from the
if blood glucose levels drops it is important that insulin secretion stops
The control of insulin secretion
Use notes from lesson to
Diabetes Mellitus
Diabetes mellitus is a disease in which blood glucose concentrations cannot be controlled
Hyperglycaemia is the state in which the…read more

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Certain factors seem to bring an earlier onset of type II diabetes:
a diet high in sugars particularly, refined sugar
being of Asian of Afro-Caribbean origin
family history
Treatment of diabetes
Type II diabetes is usually treated with careful monitoring and control of the diet
Care is taken to match the carbohydrate intake and use
This may eventually be supplemented by insulin injections or use of other drugs which slow
down the absorption of glucose from the digestive system
Type I diabetes is treated…read more


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