Carbohydrate Metabolism Overview

Questions and Answers

What is the primary hormone responsible for initiating glycogenesis in the body?

Insulin.

List two effects of increased plasma insulin on organs such as the liver and muscle.

Facilitating glucose entry through GLUT channels and increasing glucose metabolism.

How does insulin affect the action of glucagon in the body?

Insulin inhibits glucagon's catabolic release of glucose.

What is the role of adrenaline in the context of glucose metabolism in experimental rabbits?

Adrenaline can increase blood glucose levels by promoting glycogenolysis. Signup and view all the answers

Describe a safe method for taking blood samples from rabbits in an experimental setting.

Blood should be taken from the marginal ear vein of the rabbit. Signup and view all the answers

What is the concentration of glucose in a 10% glucose solution prepared with 10g of powder in 100ml of distilled water?

The concentration is 10g of glucose per 100ml, or 10% w/v. Signup and view all the answers

What is the normal concentration of glucose in blood?

About 80 mg per 100 ml of blood. Signup and view all the answers

What are the two primary sources of glucose in the body?

Food and products of metabolism. Signup and view all the answers

What major processes remove glucose from the blood?

Oxidation by tissues and conversion to glycogen in the liver and muscles. Signup and view all the answers

What is hypoglycemia and what factors contribute to it?

Hypoglycemia is a condition of low blood sugar, often caused by insulin promoting glucose oxidation and glycogen conversion. Signup and view all the answers

Which four metabolic processes coordinate the regulation of intracellular glucose?

Glycolysis, glycogenesis, glycogenolysis, and gluconeogenesis. Signup and view all the answers

What is the role of glycolysis in glucose metabolism?

Glycolysis is the enzymatic breakdown of glucose into pyruvate, reducing intracellular glucose levels. Signup and view all the answers

Explain the condition of hyperglycemia and its causes.

Hyperglycemia is the elevation of blood sugar due to the inability to store glycogen and decreased glucose utilization, often seen in diabetes mellitus. Signup and view all the answers

How does the body regulate the balance of glucose levels in the blood?

Through a balance between glucose entry from food and metabolism, and its removal by oxidation, glycogen conversion, and excretion. Signup and view all the answers

Study Notes

Blood Glucose Regulation

Blood sugar is primarily in the form of glucose, with a normal concentration of approximately 80 mg/100 ml or 0.08%.
Glucose levels are maintained through a balance of entry and removal rates, indicating effective carbohydrate metabolism.
Two primary sources of glucose are dietary intake and metabolic products.

Glucose Sources and Absorption

Dietary carbohydrates are digested into simple sugars, such as glucose, galactose, and fructose.
Glucose accounts for about 80% of all absorbed dietary sugars and enters the bloodstream via the portal circulation from the intestines.

Mechanisms of Glucose Removal

Glucose removal occurs through:
- Oxidation by tissues (glycolysis).
- Conversion into glycogen in the liver and muscle.
- Excretion through urine.
Profound hypoglycemia can occur when both oxidation and glycogen synthesis are enhanced by insulin administration.

Diabetes Mellitus and Hyperglycemia

In contrast, the absence of insulin in diabetes mellitus results in the inability to store glycogen and reduced oxidative utilization, leading to elevated blood sugar (hyperglycemia).

Metabolic Processes for Glucose Regulation

Key metabolic processes that regulate intracellular glucose include:
- Glycolysis: Converts glucose into pyruvate, producing ATP; reduces intracellular glucose levels.
- Glycogenesis: An anabolic process that synthesizes glycogen from glucose, primarily in the liver and muscle, initiated by insulin.
- Glycogenolysis: Breaks down glycogen into glucose when needed.
- Gluconeogenesis: Generates glucose from non-carbohydrate sources.

Insulin's Role

Insulin promotes glucose uptake and metabolism by:
- Facilitating the synthesis and cellular expression of glucose transporters (GLUT).
- Increasing glucose utilization and storage.
- Suppressing glucagon action to reduce glucose release.
- Enhancing lipid production and promoting cell growth and differentiation.

Experimental Animal Procedure

Rabbits are chosen as experimental animals, requiring a calm and confident approach during handling.
Avoid sudden movements and minimize noise to reduce stress and pain.
Blood samples are collected from the marginal ear vein.
Insulin dosage is 10 mg of soluble Lente insulin (40 IU per cc).
Equipment needed includes disposable syringes, glucometers, glucose test strips, and surgical blades.
A glucose solution is prepared, mixing 10 g of glucose powder in 100 ml of distilled water.
Adrenaline injection requires 2 cc for specific experiments.

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Description

This quiz explores the regulation of blood glucose levels and the importance of maintaining normal concentrations for health. It delves into how the body balances glucose entry and exit from the bloodstream, highlighting the significance of carbohydrate metabolism. Test your knowledge on these vital concepts.