Carbohydrates and Pancreatic Hormones

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Questions and Answers

What is the primary role of somatostatin in the pancreas?

Inhibits the action of insulin and glucagon (correct)

Stimulates growth hormone release

Enhances glycogenolysis

Promotes insulin secretion

Which cells in the islets of Langerhans produce insulin?

Delta cells

Beta cells (correct)

Acinar cells

Alpha cells

What is the effect of glucagon on blood glucose levels?

Lowers blood glucose levels

Regulates carbohydrate metabolism

Increases blood glucose levels (correct)

Has no effect on blood glucose levels

Which hormone promotes gluconeogenesis?

Glucagon Signup and view all the answers

What is the primary function of ACTH in the endocrine system?

Promotes adrenal hormone production Signup and view all the answers

Which carbohydrate is primarily composed of two monosaccharides?

Sucrose Signup and view all the answers

Which carbohydrate serves as the main storage form of glucose in humans?

Glycogen Signup and view all the answers

Which process is NOT promoted by carbohydrates?

Protein synthesis Signup and view all the answers

Which monosaccharide is commonly found in milk and dairy products?

Galactose Signup and view all the answers

What effect do thyroid hormones have in relation to metabolism?

Stimulate gluconeogenesis Signup and view all the answers

Which of these carbohydrates is considered a polysaccharide?

Starch Signup and view all the answers

What is the primary function of glycogenolysis?

Break down glycogen into glucose Signup and view all the answers

Which disaccharide is made from glucose and fructose?

Sucrose Signup and view all the answers

What is the primary role of amylase as an exocrine gland?

Breaking down ingested complex carbohydrates Signup and view all the answers

Which hormone is synthesized by the Beta cells of the Islets of Langerhans?

Insulin Signup and view all the answers

What effect does insulin have on glycogen?

Promotes glycogenesis Signup and view all the answers

When is glucagon typically released?

During fasting and stress Signup and view all the answers

What condition is indicated by a fasting blood sugar level greater than 126 mg/dL?

Hyperglycemia Signup and view all the answers

What is the renal threshold for glucose, above which glucose appears in urine?

160-180 mg/dL Signup and view all the answers

Which of the following metabolic processes does glucagon promote?

Glycogenolysis Signup and view all the answers

What typically results from an imbalance between glucose utilization and production?

Hypoglycemia Signup and view all the answers

What is a key indicator of hyperglycemia in laboratory findings?

Increased glucose levels in plasma Signup and view all the answers

What does lipogenesis refer to?

Synthesis of fatty acids from carbohydrates Signup and view all the answers

What does an increase in glucose concentration lead to in terms of end color intensity?

It is directly proportional to end color intensity. Signup and view all the answers

Which method generates NADH that is proportional to glucose concentration?

Glucose dehydrogenase method. Signup and view all the answers

For patients with hemolytic disease, what is added to shorten the time necessary to reach equilibrium?

Mutarotase. Signup and view all the answers

What is the primary role of glucagon in the body?

Promoting gluconeogenesis Signup and view all the answers

Which of the following is the diagnostic criterion for diabetes mellitus (DM) based on fasting blood sugar (FBS)?

FBS > 126 mg/dl Signup and view all the answers

What happens in the polarographic glucose oxidase method?

It measures the rate of oxygen consumption which is proportional to glucose concentration. Signup and view all the answers

Which adrenal cortex zones secrete glucagon and other glycemic hormones?

Zona fasciculata and zona reticularis Signup and view all the answers

What blood glucose concentration is critical for diagnosing hypoglycemia?

50-55 mg/dL Signup and view all the answers

What is used in the glucose oxidase method to prevent H2O2 from re-forming oxygen?

Molybdate. Signup and view all the answers

What is included in Whipple's triad for diagnosing hypoglycemia?

Symptoms, low blood glucose, and relief after glucose administration Signup and view all the answers

What is the range for short-term glucose control indicated for diabetes management?

3-6 weeks. Signup and view all the answers

What is the effect of high levels of ascorbic acid on blood glucose measurement?

Decreases plasma glucose levels Signup and view all the answers

What does the term glycosylated refer to in the context of glucose testing?

The attachment of glucose to proteins such as albumin. Signup and view all the answers

How does HbA1c level correlate to plasma glucose levels?

Every 1% change corresponds to 35 mg/dL change in glucose Signup and view all the answers

What type of glucose is produced through gluconeogenesis?

Both a-D and b-D glucose Signup and view all the answers

Which of the following substances can inhibit glucocorticoids?

Bilirubin Signup and view all the answers

Study Notes

Carbohydrates and Energy Sources

Hydrates of aldehyde and ketone derivatives are vital sources of energy.
Carbohydrates are the primary energy source for the body; the brain consumes the most carbohydrates.

Glycogen, Glucose, and Simple Sugars

Glycogen is stored glucose in humans and is essential for maintaining blood glucose levels.
Monosaccharides include simple sugars like glucose, galactose, and fructose.
Disaccharides consist of two monosaccharides; examples include:
- Lactose: galactose + glucose
- Sucrose: fructose + glucose
- Maltose: glucose + glucose
Polysaccharides are composed of many monosaccharides; starch and cellulose are key examples.

Pancreatic Hormones

The pancreas serves both endocrine (hormone release) and exocrine (digestion) functions.
Insulin:
- Synthesized by beta cells; lowers blood glucose by promoting glycogenesis, lipogenesis, and glycolysis.
Glucagon:
- Produced by alpha cells; increases blood glucose through glycogenolysis.
Somatostatin:
- Synthesized by delta cells; inhibits insulin and growth hormone actions.
Amylase:
- Enzyme responsible for breaking down complex carbohydrates; its increase is an early marker of pancreatitis.

Hormonal Regulation of Blood Glucose

Insulin promotes glucose entry into cells and glycogenesis while inhibiting glycogenolysis.
Glucagon promotes glucose release from glycogen stores during fasting or stress.
Cortisol and corticosteroids increase blood glucose through gluconeogenesis and are secreted by the adrenal cortex.

Clinical Conditions of Carbohydrate Metabolism

Hyperglycemia: Increased blood glucose concentration, defined as fasting blood sugar (FBS) >126 mg/dL.
- Symptoms include increased plasma/urine glucose, ketones in serum/urine, and metabolic acidosis.
Diagnostic criteria for diabetes mellitus (DM):
- FBS >126 mg/dL
- 2-hour oral glucose tolerance test (OGTT) >200 mg/dL
- HbA1c >6.5%
Hypoglycemia: Decreased blood glucose levels, typically defined as <70 mg/dL.
- Symptoms arise from an imbalance between glucose production and utilization.

Diagnostic Methods for Glucose Measurement

Glucose Dehydrogenase Method: Measures NADH production proportional to glucose concentration.
Polarographic Glucose Oxidase Method: Measures oxygen consumption related to glucose concentration.

Additional Notes

The HbA1c test measures long-term glucose control; a 1% change corresponds to a 35 mg/dL change in plasma glucose.
Fructosamine serves as a short-term glucose control marker, reflecting the previous 1-2 weeks of glucose levels.

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Description

This quiz covers the essential aspects of carbohydrates as energy sources, including their structure and types such as glycogen and simple sugars. It also explores the role of pancreatic hormones like insulin and glucagon in regulating blood glucose levels.