Skin and Temperature Control
Skin protects and helps regulate temperature.
About this topic
Skin is the body's largest organ, with the epidermis (waterproof barrier), dermis (blood vessels, nerve endings, sweat glands, hair follicles) and fatty hypodermis for insulation. It protects against germs, UV and water loss, senses touch, and makes vitamin D.
For temperature control, when hot sweat glands release sweat that evaporates, and blood vessels widen (vasodilation); when cold, hairs rise, shivering generates heat and vessels narrow (vasoconstriction). The hypothalamus acts as the thermostat.
When you are hot, sweat glands release sweat, and its evaporation takes heat from the body; blood vessels near the surface widen (vasodilation), so more heat radiates. When cold, vessels narrow (vasoconstriction), hairs stand up to trap air, and muscles shiver to generate heat. Fat under the skin insulates.
Skin also makes vitamin D when exposed to sunlight and senses touch, pressure and pain. Melanin gives colour and protects against UV, and too much sun exposure raises the risk of skin cancer, so sunscreen helps. Burns damage the layers and the ability to control temperature. A common misconception is that blood vessels move closer to the skin surface when warm; instead, the vessels remain in place and simply widen to let more blood flow.
Key ideas
- Sweat evaporates to cool
- Blood vessels dilate or constrict
- Hairs trap warm air
Quick check
Use cases: where Skin and Temperature Control helps
- Homework: review the key idea behind Skin and Temperature Control before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Skin and Temperature Control without notes.
- Visual learning: play with the interactive lab to see how Skin and Temperature Control changes when you adjust its inputs.
- Teaching a friend: explain Skin and Temperature Control in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is Skin and Temperature Control?
Skin protects and helps regulate temperature.
What will I learn in Skin and Temperature Control?
Sweat evaporates to cool. Blood vessels dilate or constrict. Hairs trap warm air.
Is Skin and Temperature Control part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Skin and Temperature Control lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Skin and Temperature Control?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.