The source of glucose for maintaining normal level when the blood glucose begins to fall is?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Biochemistry & Nutrition

Medium

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Explanation

When blood glucose levels start to decrease between meals, the pancreas reduces insulin secretion and increases glucagon secretion.
Glucagon is a hormone that acts on the liver, signaling it to break down its stored glycogen into glucose.
This process, known as glycogenolysis, provides a rapid release of glucose into the bloodstream to prevent hypoglycemia.
Liver glycogen stores are the body's primary, immediate buffer against falling blood glucose in the early fasting state (4-12 hours after a meal).

Option A: Ingested food is the source of glucose during the absorptive phase (right after eating), not when blood glucose levels are falling between meals.
Option C: Gluconeogenesis is a slower process that becomes the main source of glucose only during prolonged fasting (typically after 12-24 hours), once liver glycogen stores are significantly depleted.
Option D: The bacteria in the human intestine (intestinal flora) do not produce glucose for systemic circulation and are not involved in maintaining blood glucose homeostasis.

Clinical Relevance

Nursing practice connection: Knowing Regulation of Blood Glucose Homeostasis helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding this sequence is crucial for nurses when educating patients with diabetes about the risks of skipping meals or exercising without adequate carbohydrate intake, which can deplete glycogen stores and lead to hypoglycemia.
This knowledge underpins the emergency treatment of hypoglycemia. Fast-acting carbohydrates are given to conscious patients for a quick glucose boost, while glucagon injections are used in unconscious patients to stimulate the liver's release of stored glucose.
What if the patient has a glycogen storage disease (GSD)? In that case, their ability to break down liver glycogen is impaired. They would become hypoglycemic much more quickly during fasting and would depend heavily on gluconeogenesis, requiring frequent, specialized meals to maintain blood glucose levels.

How to Approach the Question

First, analyze the question to identify the key phrase: 'when the blood glucose begins to fall'.
Recognize that this phrase refers to the early post-absorptive state, which occurs a few hours after a meal.
Recall the body's sequential mechanisms for maintaining glucose levels: 1. Dietary intake, 2. Liver glycogenolysis, 3. Gluconeogenesis.
Evaluate the options based on this timeline. 'Ingested food' is the source during absorption, not after. 'Gluconeogenesis' is the source for long-term fasting, not when glucose just 'begins to fall'.
Eliminate 'Intestinal flora' as it is not a source of systemic glucose.
Conclude that 'Liver glycogen' is the correct answer as glycogenolysis is the body's first line of defense against falling blood glucose between meals.

Concept Tested & Keywords

Concept Tested: Regulation of Blood Glucose Homeostasis
Stem keywords: source of glucose, maintaining normal level, blood glucose begins to fall
Lead-in keywords: is

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