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D3.3.4—Diabetes

Diabetes disrupts blood glucose control through insufficient insulin production or reduced cellular response to insulin in human physiology in human physiology.

Syllabus
First assessment 2025
Objective
D3.3.4
Level
HL

Exam analysis

Chance of appearing9%of analysed past papers
Latest appearanceMay 2022
Most common paperPaper2
Typical marks1–2

Common command terms

  • Describe
  • Identify
  • Explain
  • State
  • Discuss
  • Analyse
  • Outline

Recent exam appearances

May 2022Paper2 ["HL"] · TZ25(b)(ii)[ 1 ]D3.3.4—Diabetes
May 2022Paper2 ["HL"] · TZ25(b)(i)[ 2 ]D3.3.4—Diabetes
November 2019Paper3 ["HL"] · TZ019(e)[ 1 ]D3.3.4—Diabetes
May 2017Paper1 ["HL"] · TZ125[ 1 ]D3.3.4—Diabetes
November 2016Paper3 ["HL"] · TZ019(b)[ 2 ]D3.3.4—Diabetes

Coverage 2013–2022 · Updated 16 Jul 2026

Type 1 and Type 2 Diabetes Disrupt Different Links in Glucose Control

Feature Type 1 diabetes Type 2 diabetes
primary failure autoimmune destruction of beta cells reduced target-cell response to insulin; beta-cell function may later decline
insulin signal little or none produced present but less effective
common management principle replace insulin and monitor glucose improve response and glucose balance through individualized diet, activity and medication
association genetic susceptibility and environmental triggers age, family history, inactivity and excess body fat are risk factors

A risk factor changes probability; it is not a single sufficient cause. Type 2 diabetes should not be reduced to “eating sugar,” and type 1 is not caused by lifestyle.

Both can produce persistent hyperglycaemia, glucose in urine and long-term damage to blood vessels, kidneys, retina and nerves if control remains poor.

A Glucose Tolerance Curve Tests How Quickly the Control System Recovers

  1. Measure fasting blood glucose.
  2. Give a standard oral glucose dose.
  3. Measure blood glucose at defined times after ingestion.
  4. Compare peak height and recovery toward the fasting range.
Curve feature Effective regulation Impaired regulation
starting value within expected fasting range may already be elevated
post-dose peak rises then turns downward often higher or prolonged
later value approaches the starting range remains elevated longer

The curve shows glucose handling under a standardized challenge. Diagnosis uses clinical thresholds and context; one graph alone does not identify the exact cellular cause.

Homeostasis Uses the Same Logic with Different Sensors and Effectors

regulated variable leaves its acceptable range → receptor detects the direction of deviation → coordinator selects an opposing response → effectors alter transfer, storage or metabolism → deviation shrinks → corrective signal declines

System Sensor / coordinator High-side response Low-side response
blood glucose pancreatic islet cells beta cells, insulin, uptake and storage alpha cells, glucagon, liver glucose release
core temperature thermoreceptors and hypothalamus vasodilation and sweating vasoconstriction, shivering and metabolic heat

For any homeostatic explanation, name the variable, direction of deviation, detector, signal, effector action and why that action reverses the deviation.

Diabetes exam focus

[ 5 ]

Outline type II diabetes.

Concept essentials

  • Type I diabetes involves insufficient insulin production.
  • Type II diabetes involves reduced target-cell response to insulin.
  • Diabetes can cause high blood glucose and glucose loss in urine.