Endocrine and glucose reg (metab ppt)

Pancreas - Function

Acts as both an endocrine and exocrine gland; secretes insulin, glucagon, and digestive enzymes.

Endocrine role of pancreas

Regulates blood glucose through insulin (lowers) and glucagon (raises) secretion.

Islets of Langerhans

Clusters of endocrine cells within the pancreas that regulate glucose homeostasis.

Beta cells

Located in the islets; secrete insulin in response to high blood glucose.

Alpha cells

Located in the islets; secrete glucagon when blood glucose is low.

Insulin - Function

Facilitates glucose uptake by cells, promotes glycogen storage, and inhibits gluconeogenesis.

Glucagon - Function

Stimulates glycogen breakdown (glycogenolysis) and glucose synthesis (gluconeogenesis) to raise blood sugar.

Normal fasting blood glucose

70-110 mg/dL (varies slightly by lab).

Postprandial blood glucose (2 hours after eating)

< 140 mg/dL.

Glycogen

Stored form of glucose found in the liver and skeletal muscle.

Glycogenolysis

Breakdown of glycogen to glucose for energy during fasting or stress.

Gluconeogenesis

Formation of glucose from non-carbohydrate sources (amino acids, fats) in the liver.

Insulin release triggers

High blood glucose, amino acids, fatty acids, GI hormones.

Glucagon release triggers

Low blood glucose, high protein intake, strenuous exercise.

Effect of insulin deficiency

Cells cannot utilize glucose → hyperglycemia, glycosuria, polyuria, polydipsia, polyphagia.

Hyperglycemia

Excess glucose in the blood; can lead to dehydration, ketoacidosis, or long-term vascular damage.

Hypoglycemia

Blood glucose < 70 mg/dL; can result from too much insulin, too little food, or increased activity.

Symptoms of hypoglycemia

Sweating, shakiness, confusion, headache, blurred vision, tachycardia, irritability.

Body response to hypoglycemia

Release of epinephrine and glucagon to increase glucose levels.

Insulin effect on potassium

Promotes movement of potassium into cells; may cause hypokalemia with large doses.

Counter-regulatory hormones

Hormones that oppose insulin: glucagon, cortisol, epinephrine, growth hormone.

Metabolic role of liver

Major site for glycogen storage, glucose production, and metabolism of carbs, fats, and proteins.

Relationship between insulin and glucose uptake

More insulin → more glucose enters muscle and adipose cells; lack of insulin → glucose remains in blood.

Primary energy source for the brain

Glucose; the brain cannot store or synthesize glucose and depends on continuous supply.

Homeostasis in glucose regulation

Balance between insulin and glucagon maintains blood sugar within normal range.

Diabetes mellitus - basic concept

Group of metabolic disorders marked by chronic hyperglycemia from insulin deficiency or resistance.

Long-term effects of poor glucose control

Neuropathy, nephropathy, retinopathy, vascular damage, delayed wound healing.