In what form is Carbohydrate stored in the Liver?

Raj. CHO -2020

Applied Nutrition & Dietetics

Easy

Appeared in: Raj. CHO -2020

Explanation

The liver stores excess carbohydrates as a large, branched polysaccharide called glycogen.
This process, known as glycogenesis, is stimulated by insulin and allows the body to save glucose for later use.
When blood sugar is low, the liver breaks down glycogen (glycogenolysis) to release glucose into the bloodstream, thereby maintaining stable blood glucose levels.
Glycogen is a more highly branched polymer of glucose than starch, which is the storage form in plants.

Option A: Glucose is the primary circulating sugar used for immediate energy by cells; it is the monomer unit that makes up glycogen but is not the storage form itself.
Option B: Sucrose is a dietary disaccharide (table sugar). The body breaks it down into glucose and fructose in the small intestine; it is not stored in its original form.
Option C: Galactose is a monosaccharide derived from lactose (milk sugar). The liver metabolizes it, primarily by converting it into glucose. It is not stored as galactose.

Visual 1: Diagram: A visual representation of a liver cell (hepatocyte) showing glucose entering and being polymerized into a branched glycogen molecule (glycogenesis), and the reverse process of glycogen breaking down into glucose (glycogenolysis).
Visual 2: Flowchart: A flowchart illustrating carbohydrate metabolism, showing dietary carbohydrates being broken down to glucose, which is then used for energy, stored as glycogen in the liver and muscles, or converted to fat.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Carbohydrate Metabolism and Storage as background academic context rather than a clinical decision trigger.
Understanding glycogen metabolism is fundamental in managing diabetes mellitus. Insulin facilitates glycogen storage, while a lack of insulin or insulin resistance impairs this process, contributing to hyperglycemia.
In cases of severe hypoglycemia, a glucagon injection is administered. Glucagon acts on the liver to stimulate rapid glycogenolysis, releasing glucose into the blood and raising blood sugar levels.
Glycogen Storage Diseases (GSDs) are genetic disorders where defects in enzymes for glycogen synthesis or breakdown lead to abnormal glycogen accumulation or an inability to access stored glucose, causing symptoms like hypoglycemia, muscle weakness, and liver enlargement.

How to Approach the Question

First, identify the key terms in the question: 'Carbohydrate', 'stored', and 'Liver'. This directs you to the topic of metabolic storage.
Recall the different forms and functions of carbohydrates in the body. Differentiate between simple sugars (monosaccharides like glucose), dietary sugars (disaccharides like sucrose), and storage polysaccharides.
Consider the role of the liver in blood glucose regulation. The liver acts as a buffer, storing glucose when it's abundant and releasing it when it's scarce.
Evaluate the options: Glucose is the transport form, not the storage form. Sucrose and Galactose are dietary sugars that are metabolized, not stored directly.
Conclude that Glycogen is the specific polysaccharide used by animals, particularly in the liver and muscles, for storing glucose.

Concept Tested & Keywords

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