Blood Glucose, Diabetes, & Metabolism

What causes diabetes?

Glucose dysregulation leading to chronic hyperglycemia.

What happens in a healthy person regarding insulin?

Insulin binds to the insulin receptor and the cell responds normally.

What is Type 1 diabetes?

Pancreas fails to produce insulin.

What is Type 2 diabetes?

Cells fail to respond properly to insulin; insulin is unable to bind insulin receptors.

What is gestational diabetes?

Diabetes that begins late in pregnancy (≈4%) caused by placental hormones that block insulin receptors.

What are risks of gestational diabetes?

Macrosomia due to excess nutrients and increased risk of diabetes in the baby.

How does diabetes impact circulation?

AGE (advanced glycation end) products bind collagen in arteries, triggering inflammation and accelerating plaque buildup.

What is glycation?

The non-enzymatic reaction of sugar with proteins (Maillard reaction).

How does diabetes impact the eyes?

AGE accumulation leads to cataracts by reducing blood supply and promoting debris clumping in the lens.

What causes glaucoma in diabetes?

Glucose converts to sorbitol and fructose, which cannot leave the eye, increasing pressure and damaging the retina.

How does diabetes affect peripheral nerves?

Sorbitol and fructose accumulate in nerves, causing osmotic stress and altering membrane potential.

What is a result of diabetic nerve damage?

Failure to notice trauma due to impaired nerve function.

How does diabetes impair immunity?

High glucose levels limit and dysregulate neutrophil synthesis.

Why are infections more common in diabetics?

High sugar in blood and tissues promotes bacterial growth and faster infection development.

How do sorbitol and fructose affect the kidneys?

They damage nephrons.

How do AGEs affect kidney vasculature?

They damage blood vessels and interfere with reabsorptive processes.

What happens when kidneys fail to reabsorb properly due to AGE damage?

Proteins are lost in the urine.

What is the main goal of lifestyle modifications for diabetes?

Minimize spikes in blood sugar.

Why do small, frequent meals help diabetics?

They reduce post-meal glucose spikes.

Why are low glycemic index foods recommended for diabetes?

They slow glucose absorption and reduce blood sugar spikes.

How does soluble fiber help regulate blood glucose?

Slows stomach emptying, traps sugars for slower absorption, inhibits amylase, increases insulin sensitivity.

What lifestyle change is especially important for Type II diabetes?

Weight loss.

Why does weight loss help Type II diabetes?

Smaller adipose cells become more sensitive to insulin.

How does physical activity help Type II diabetes?

Increases insulin sensitivity and glucose uptake.

What is the treatment for Type I diabetes?

Exogenous insulin via pumps or injections.

What medication reduces glucose production in the liver for Type II diabetes?

Metformin.

What do sulfonylureas do?

Increase insulin sensitivity in peripheral tissues and stimulate beta cells to produce more insulin.

What hormone is released by alpha cells in the pancreas?

Glucagon.

What does glucagon do in the liver?

Stimulates glycogen breakdown to release glucose into the bloodstream.

What hormones does the hypothalamus/pituitary stimulate during low blood sugar?

Epinephrine and glucocorticoids.

What do glucocorticoids promote during hypoglycemia?

Gluconeogenesis from amino acids.

What enzyme is activated to break down fat during hypoglycemia?

Hormone-sensitive lipase.

What happens to fatty acids during hypoglycemia?

They are sent to muscles to make ATP.

How do glucocorticoids affect muscle during hypoglycemia?

They promote breakdown of muscle into amino acids for gluconeogenesis.

What is hypoglycemia?

Abnormally low blood glucose levels.

What is fasting hypoglycemia?

Low blood glucose because liver cannot break down glycogen due to hypoactive alpha cells.

What is reactive hypoglycemia?

Post-meal drop in glucose due to hypersensitive beta cells (e.g., tumors).

What other conditions can cause hypoglycemia?

Pituitary tumors, adrenal tumors, liver disease.

What enzymes begin triglyceride breakdown in the mouth and stomach?

Lingual and gastric lipase.

How do fatty acids stimulate digestion?

They stimulate CCK to release bile from the gallbladder and pancreatic lipase.

What does bile do to triglycerides?

Emulsifies them, like soap emulsifies grease.

What do micelles do?

Allow fatty acids to be absorbed into intestinal cells.

What happens to fatty acids inside intestinal cells?

They are rebuilt into triglycerides within chylomicrons.

How are triglycerides packaged for circulation from the liver?

As very low-density lipoprotein (VLDL).

What does a chylomicron do?

Carries fat from epithelial cells to the liver.

What does VLDL do?

Distributes fat from the liver to muscle and adipose tissue.

What is IDL?

Formed by removal of triglycerides from VLDL by muscle and adipose tissue.

What is LDL?

Formed from IDL & VLDL; delivers cholesterol to tissues.

What is HDL?

Performs reverse cholesterol transport from peripheral tissues to the liver.

What does lipoprotein lipase (LPL) do?

Breaks down triglycerides into fatty acids and glycerol in capillaries of adipose, liver, and muscle tissue.

How does atherosclerosis begin?

LDL enters injured artery walls.

What is HDL's role in atherosclerosis?

Removes LDL from arteries.

What happens to LDL in arteries?

It is oxidized and triggers immune response.

What forms fatty streaks?

WBC aggregation at LDL sites.

How does plaque form?

Calcium accumulation over fatty streaks decreases vessel diameter.

What are the consequences of plaque buildup?

Thrombosis, stroke, or heart attack.

What class of drugs blocks cholesterol synthesis and increases LDL receptor sensitivity?

Statins.

How do unsaturated fats affect LDL & IDL receptors?

They increase receptor sensitivity.

How can overall calorie reduction help atherosclerosis?

Decreases LDL levels.

How does stress reduction affect atherosclerosis?

Decreases VLDL circulation.

How does nicotine affect cholesterol?

Decreases HDL and increases LDL.

Can the energy in the amino group of proteins be used?

No, it is excreted as urea.

What happens to excess protein calories in a positive energy balance?

Converted to fat.

What role does HCl play in protein digestion?

Unfolds proteins.

What role does pepsin play in protein digestion?

Breaks down proteins into amino acids.

What are consequences of a low-protein diet with sufficient calories?

Impaired growth, high infection rates, "pot belly," fatty liver, impaired motor/cognitive development, edema.

Why does impaired growth occur with low dietary protein?

↓ anabolic reactions due to incomplete proteins.

Why is there a high rate of infection with low dietary protein?

↓ antibody synthesis.

Why does a "pot belly" appear in protein malnutrition?

Worms due to ↓ hygiene.

Why does fatty liver occur in protein malnutrition?

↓ VLDL to transport fat.

Why does edema occur in protein malnutrition?

↓ osmotic pressure due to very low serum protein.