What is the primary action of insulin in the human body?

Appeared in: DSSSB 6 September 2024

Explanation

Insulin's main function is to lower blood glucose levels after a meal.
It acts like a key, binding to receptors on muscle, fat, and liver cells, which allows glucose to move from the blood into the cells.
This process is called facilitated diffusion, and it involves the translocation of glucose transporters (like GLUT4) to the cell membrane.
By moving glucose into cells, insulin effectively reduces the concentration of glucose circulating in the bloodstream.

Option A: This is the opposite of insulin's function. Insulin's primary role is to decrease blood glucose levels.
Option C: This process, called glycogenolysis, is inhibited by insulin. Insulin promotes the storage of glucose as glycogen (glycogenesis).
Option D: Insulin is an anabolic (building) hormone. It promotes, rather than inhibits, protein synthesis by increasing amino acid uptake into cells.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Primary physiological action of insulin as background academic context rather than a clinical decision trigger.
Understanding insulin's action is fundamental to managing diabetes mellitus. In Type 1 diabetes, the body doesn't produce insulin, requiring external administration. In Type 2 diabetes, cells become resistant to insulin's effects.
Nurses must monitor patients on insulin therapy for signs of hypoglycemia (low blood sugar), which can occur if too much insulin is given or if a meal is skipped. Symptoms include sweating, shakiness, confusion, and tachycardia.
Patient education is critical. Nurses teach patients how to administer insulin, monitor their blood glucose, and recognize the symptoms of both high (hyperglycemia) and low (hypoglycemia) blood sugar.

How to Approach the Question

First, identify the core subject of the question, which is 'insulin' and its 'primary action'.
Recall the fundamental role of insulin in glucose homeostasis. Its main job is to lower blood glucose after it rises, typically after a meal.
Evaluate each option based on this core function.
Option A describes the opposite effect, which is characteristic of glucagon.
Option B directly describes the mechanism by which insulin lowers blood glucose – moving it into cells.
Option C describes glycogenolysis, an action stimulated by glucagon, not insulin.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 3 p. 2-4

E6 Physiology Essentials Sembulingam 10e Part 2 p. 63-65

Practise the full DSSSB 6 September 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.