Homeostasis

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Homeostasis

• The control of blood sugar levels
• (The Regulation of Glucose in the blood)

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The Regulation of Glucose in the Blood

• Normal glucose level is about 5 to 5.5 mmol dm-3
• If this level rises too high it would affect the
  water content of the body.
• If glucose appears in the urine (glycosuria)
  water reabsorbtion in the kidney will be reduced.
• If glucose level in the tissue fluid is high
  water will be lost from cells by osmosis.

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The Regulation of Glucose in the Blood

• If levels fall below 3 mmol dm-3 (hypoglycaemia)
  this would lead to a loss of consciousness
  (coma).
• If level goes above 10 mmol dm-3
  (hyperglycaemia) glucose will appear in the
  urine, the pH of the blood would fall and this
  also leads to coma.
• Both conditions are a feature of diabetes
  mellitus.

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Insulin is the key that allows special gates
for sugar transport across cell membranes to be
opened
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The Regulation of Glucose in the Blood

• If insulin can not be made the glucose is not
  removed from the blood and glycogen is broken
  down into sugar resulting in high blood sugar
  levels. This is Type 1 or insulin-dependent
  diabetes.
• Possibly caused by the destruction of beta-cells
  due to viral infection.
• It seems the immune system makes a mistake and
  cells that normally protect you from germs attack
  your beta cells instead

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The Regulation of Glucose in the Blood

• Type II (insulin-independent diabetes) is linked
  to the ageing process and obesity often
  controlled by controlling the diet.

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Normal blood sugar level
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Normal blood sugar level
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If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
Normal blood sugar level
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If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
Normal blood sugar level
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Detector the alpha and beta cells of the Islets
of langerhans. The alpha cells stop secreting
glucagon and the beta cells secrete insulin
If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
Normal blood sugar level
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Detector the alpha and beta cells of the Islets
of langerhans. The alpha cells stop secreting
glucagon and the beta cells secrete insulin
If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
Normal blood sugar level
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Detector the alpha and beta cells of the Islets
of langerhans. The alpha cells stop secreting
glucagon and the beta cells secrete insulin
If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
Normal blood sugar level
Effector liver cells stop breaking glycogen
down due to drop in glucagon most body cells
increase uptake and use of glucose due to rise in
insulin
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Detector the alpha and beta cells of the Islets
of langerhans. The alpha cells stop secreting
glucagon and the beta cells secrete insulin
If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
Normal blood sugar level
Effector liver cells stop breaking glycogen
down due to drop in glucagon most body cells
increase uptake and use of glucose due to rise in
insulin
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Detector the alpha and beta cells of the Islets
of langerhans. The alpha cells stop secreting
glucagon and the beta cells secrete insulin
If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
Normal blood sugar level
Effector liver cells stop breaking glycogen
down due to drop in glucagon most body cells
increase uptake and use of glucose due to rise in
insulin
Blood glucose stabilised
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Detector the alpha and beta cells of the Islets
of langerhans. The alpha cells stop secreting
glucagon and the beta cells secrete insulin
If blood sugar rises This could be the Result of
ingestion of Food or release of Glucose from the
liver
negative feedback control loop
Normal blood sugar level
Effector liver cells stop breaking glycogen
down due to drop in glucagon most body cells
increase uptake and use of glucose due to rise in
insulin
Blood glucose stabilised
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Normal blood sugar level
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Normal blood sugar level
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Normal blood sugar level
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods
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Normal blood sugar level
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods
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Normal blood sugar level
Detector alpha and beta cells of the Islets of
Langerhans. The alpha cells secrete glucagon and
the beta cells stop secreting insulin
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods
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Normal blood sugar level
Detector alpha and beta cells of the Islets of
Langerhans. The alpha cells secrete glucagon and
the beta cells stop secreting insulin
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods
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Effector liver cells break down glycogen into
glucose due to rise in glucagon most body cells
decrease uptake and use of glucose due to fall in
insulin
Normal blood sugar level
Detector alpha and beta cells of the Islets of
Langerhans. The alpha cells secrete glucagon and
the beta cells stop secreting insulin
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods
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Effector liver cells break down glycogen into
glucose due to rise in glucagon most body cells
decrease uptake and use of glucose due to fall in
insulin
Normal blood sugar level
Detector alpha and beta cells of the Islets of
Langerhans. The alpha cells secrete glucagon and
the beta cells stop secreting insulin
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods
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Effector liver cells break down glycogen into
glucose due to rise in glucagon most body cells
decrease uptake and use of glucose due to fall in
insulin
Blood glucose stabilised
Normal blood sugar level
Detector alpha and beta cells of the Islets of
Langerhans. The alpha cells secrete glucagon and
the beta cells stop secreting insulin
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods
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Effector liver cells break down glycogen into
glucose due to rise in glucagon most body cells
decrease uptake and use of glucose due to fall in
insulin
Blood glucose stabilised
Normal blood sugar level
negative feedback control loop
Detector alpha and beta cells of the Islets of
Langerhans. The alpha cells secrete glucagon and
the beta cells stop secreting insulin
If blood glucose falls This could be the result
of a high rate of cellular uptake and use of
glucose or failure to ingest carbohydrate foods