REGULATION OF BODY GLUCOSEBY: SYEDA

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DEFINITION

Blood sugar regulation is the process by which the levels of blood sugar, primarily glucose, are maintained by the body within physiological limits

A balance between two sets of factors:

A. Rate of Glucose entrance into

blood stream

B. Rate of removal from blood stream

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What are Normal Blood Glucose Levels?

What to do when your blood glucose is too low.The amount of glucose (“sugar”, measured in mg/dL) in your blood changes throughout the day and night. Your levels will change depending upon when, what and how much you have eaten, and whether or not you have exercised.

_A normal fasting (no food for eight hours) blood sugar level is between 70 and 99 mg/dL

_A normal blood sugar level two hours after eating is less than 140 mg/dL

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Mechanisms of blood sugar regulation

Blood sugar levels are regulated by negative feedback in order to keep the body in homeostasis. The levels of glucose in the blood are monitored by the cells in the pancreas's Islets of Langerhans on one hand

& hormones of adrenal cortex & interior pituitary on other hand

these hormones work antagonistic to each other & their ratio matters instead of their values.

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HORMONES REGULATING BLOOD GLUCOSE:

hormone tissue of origin effect on blood glucose

insulin pancreatic beta cells lowers

somatostatin pancreatic gamma cells lowers

glucagon pancreatic alpha cells raises

epinephrine adrenal medulla raises

cortisol adrenal cortex raises

ACTH+Growth hormone anterior pituitary raises

Thyroxine thyriod raises

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INSULIN & GLUCAGON:

When blood glucose levels rise, insulin is secreted by the pancreas, lowering blood glucose by increasing its uptake in cells and stimulating the liver to convert glucose to glycogen, in which form it can be stored.

When blood glucose levels fall, glucagon is secreted by the pancreas, which increases blood glucose levels by stimulating the breakdown of glycogen into glucose and the creation of glucose from amino acids

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INSULIN:

glucose level effect on pancreas effect on liver effect on

glucose level

too highinsulin secreted into blood

liver converts glucose into glycogen

goes down

too lowinsulin not secreted into blood

liver does not convert glucose into glycogen

goes up

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THYROID,EPINEPHRINE & CORTISOL:

T3 and T4 bind to receptors on the mitochondria, causing an increase in the production of ATP, as well as increase in the transcription of genes that help utilize glucose and produce ATP, resulting in higher metabolism of the cell

Epinephrine (adrenaline) is released from nerve endings and the adrenals, and acts directly on the liver to promote sugar production (via glycogenolysis)

Cortisol is a steroid hormone also secreted from the adrenal gland. It makes fat and muscle cells resistant to the action of insulin, and enhances the production of glucose by the liver.

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GROWTH HORMONE & AMYLIN:

Amylin is released along with insulin from beta cells. It has much the same effect as GLP-1. It decreases glucagon levels, which will then decrease the liver’s glucose production, slows the rate at which food empties from your stomach, and makes your brain feel that you have eaten a full and satisfying meal.

Growth Hormone is released from the pituitary, which is a part of the brain. Like cortisol, growth hormone counterbalances the effect of insulin on muscle and fat cells

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CLINICAL SIGNIFICANCE

DEVIATION FROM THE NORMAL VALUES MAY LEAD TO

HYPERGLYCEMIA HYPOGLYCEMIA

HYPER: DIABETES MELLITUS HYPERACTIVITY OF THYROIDS,PITUITARY &

ADRENAL GLANDS PANCREATITIS SEPSIS ANAESTHESIA ASPHYXIA

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HYPOGLYCEMIA:

HYPO:

OVERDOSAGE OF INSULIN INSULIN SECRETING TUMOR(INSULINOMA) STEATORRHEA SEVERE EXERCISE HYPOACTIVITY OF PREVIOUS MENTIONED

GLANDS

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Thank You