D3.3.5—Thermoregulation
Thermoregulation maintains core body temperature by detecting changes and activating heat loss or heat conservation responses in human physiology in human physiology.
- Syllabus
- First assessment 2025
- Objective
- D3.3.5
- Level
- SL
Exam analysis
Chance of appearing3%of analysed past papers
Latest appearanceMay 2017
Most common paperPaper1
Typical marks1–8
Common command terms
- Describe
- Explain
- Identify
- Outline
Recent exam appearances
May 2017Paper1 ["SL"] · TZ230[ 1 ]D3.3.5—Thermoregulation
November 2015Paper1 ["SL"] · TZ027[ 1 ]D3.3.5—Thermoregulation
May 2013Paper2 ["SL"] · TZ27(c)[ 8 ]D3.3.5—Thermoregulation
May 2012Paper2 ["SL"] · TZ17(b)[ 6 ]D3.3.5—Thermoregulation
Practice this objective
Coverage 2012–2017 · Updated 16 Jul 2026
Thermoregulation Is a Negative-Feedback Control System
Human thermoregulation detects deviation in core temperature and coordinates effectors that reverse the change.
| Control component | Role |
|---|---|
| Peripheral thermoreceptors | Detect temperature changes, especially at the skin |
| Hypothalamus | Integrates peripheral and central temperature information |
| Pituitary/thyroid pathway | Alters thyroxin signalling and therefore metabolic heat production |
| Skeletal muscle | Shivering raises respiration and heat production |
| Brown adipose tissue | Uncoupled respiration releases energy as heat |
A fall in temperature is detected, the hypothalamus coordinates reduced heat loss and increased muscle/adipose heat production, and the response decreases as core temperature recovers.
The regulated variable is core temperature; skin temperature can change more rapidly and acts partly as an early environmental signal.
Thermoregulation exam focus
Assessment in practice
1–8 marksHow it is assessed
This objective is assessed through structured response, commonly using Describe / Explain / Identify.
Command terms
Describe / Explain / Identify / Outline
What earns marks
Build the answer around this relationship: The hypothalamus coordinates body temperature control.
Representative question
Question 1
Explain the control of body temperature in humans.
Retrieve the Core Homeostasis Route
Core D3.3 is secure when every example becomes a feedback route: identify the variable, detect deviation, coordinate a response, activate effectors, and reverse the change. Glucose and temperature are the key worked examples.
- stable internal environment within narrow limits
- detects deviation from set point and reverses it
- insulin lowers high glucose; glucagon raises low glucose
- hypothalamus coordinates cooling or warming responses
Core Homeostasis
Core homeostasis answers should use a control-loop structure, not a list of responses. The response starts with the variable and set point, then explains how the body detects deviation and activates the response that reverses it. Apply that loop to glucose, diabetes, or temperature.
- Define homeostasis as maintaining stable internal conditions within narrow limits.
- Use negative feedback language: receptor, coordinator, effector, set point, and reverse the deviation.
- Apply the loop to insulin/glucagon, diabetes types, or hot/cold thermoregulation responses.
Concept essentials
- The hypothalamus coordinates body temperature control.
- Sweating and vasodilation increase heat loss when body temperature is high.
- Shivering and vasoconstriction help conserve or generate heat when body temperature is low.