What is Thermoregulation?
Thermoregulation is the body's ability to keep its core temperature close to 37°C regardless of the surrounding environment. The hypothalamus acts as a thermostat, triggering responses like sweating, shivering, and changes in blood flow to the skin.
Thermoregulation is the homeostatic process that maintains a stable internal body temperature through negative feedback, using the hypothalamus to coordinate heat-loss responses (sweating, vasodilation) and heat-gain responses (shivering, vasoconstriction).
- •Skin blood vessels constrict (vasoconstriction)
- •Shivering generates heat via muscle contraction
- •Hair stands up (piloerection) to trap air
- •Sweat glands reduce activity
- •Metabolic rate may increase
- •Skin blood vessels dilate (vasodilation)
- •Sweat glands increase sweat production
- •Sweat evaporation cools the skin
- •Behavior changes (seeking shade)
- •Metabolic heat production decreases
Step-by-step worked examples
A person walks outside in 5°C weather without a coat. Describe the thermoregulatory response.
Thermoreceptors in the skin detect the cold The hypothalamus triggers heat-conserving responses Blood vessels in the skin constrict (vasoconstriction), reducing heat loss Shivering begins, generating heat through rapid muscle contractions Result: core body temperature is protected from dropping
Someone exercises hard on a hot day and their core temperature rises to 38.5°C. Explain the cooling response.
Thermoreceptors detect the temperature rise The hypothalamus triggers heat-loss responses Skin blood vessels dilate (vasodilation), bringing warm blood near the surface Sweat glands increase sweat output, which evaporates and cools the skin Result: heat is lost to the environment and temperature falls back toward 37°C
A hiker's core temperature drops to 34°C (mild hypothermia). What thermoregulatory failure has occurred?
Heat loss to the cold environment exceeded the body's heat-generating responses Prolonged vasoconstriction and shivering were not enough to maintain 37°C As temperature keeps falling, shivering may stop entirely, worsening heat loss Result: this shows thermoregulation can be overwhelmed by extreme or prolonged cold exposure
Flashcards
Quick quiz
Q1.What is the normal human core body temperature?
Q2.Which response occurs when the body is too hot?
Q3.Which brain region controls thermoregulation?
Q4.Shivering helps the body by…
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Common mistakes
Thinking sweating only happens in hot weather. — Correct: Sweating can also occur due to exercise, fever, or stress, regardless of external temperature.
Confusing vasodilation with vasoconstriction. — Correct: Vasodilation widens vessels to lose heat; vasoconstriction narrows them to conserve heat.
Believing shivering is voluntary. — Correct: Shivering is an involuntary reflex controlled by the hypothalamus.
Assuming body temperature never changes. — Correct: It fluctuates slightly (e.g. daily rhythm, fever) but is tightly regulated around 37°C.
FAQ
What is thermoregulation?
Thermoregulation is the homeostatic process that keeps the body's core temperature stable, usually near 37°C, via the hypothalamus.
What is the formula for thermoregulation?
There's no numeric formula — it works through feedback: temperature deviation → hypothalamus response → sweating/vasodilation (cooling) or shivering/vasoconstriction (warming).
What are examples of thermoregulation?
Sweating when hot, shivering when cold, and skin vessels dilating or constricting are everyday examples.
How does the body regulate temperature when it's cold?
The hypothalamus triggers vasoconstriction, shivering, and piloerection to conserve and generate heat.