The skin
Your skin is the body’s largest organ. It keeps germs and water where they belong, senses touch and heat, and helps hold your body near 37 °C. Keeping the inside of the body steady like this is called homeostasis.
By the end of this page you can
- Explain how the skin protects the body, cools it, and shields it from the sun
- Relate each part of the skin to its job
- Put the steps of cooling down in order
- Define homeostasis, vasodilation, vasoconstriction, melanin and SPF
- Explain how the skin cools the body on a hot day
Goals tick themselves off as you try the activities below.
Photo: Ildar Sagdejev (Specious), CC BY-SA 3.0, via Wikimedia Commons. Cropped, resized, JPEG q66.
Goosebumps: tiny muscles in the skin pull each hair upright when you are cold.
How often it shows up in past papers
Paper 1 counts come from our past-paper bank of CSEC Biology Paper 1s. Paper 2 is not included yet.
Three jobs your skin does all day
The skin is a barrier, a cooling system and a sunshade. Tap each card.
Each part, its job
Tap a part to see its job.
What does it do?
Pick a part.
Skin bleaching: some lightening creams contain mercury or steroids. They can thin the skin, leave dark patches and scars, and cut melanin production, so the skin burns more easily. Mercury is also a poison.
Cooling down on a hot day
From getting too hot to cooling down: drag or tap each card into its slot.
What starts it all?
Seven terms to know cold
Say what each term means before you flip the card. Vessel questions need the word arterioles.
Six quick questions, then a real one
Pick an answer to see why it’s right or wrong.
On a hot day, the arterioles supplying the skin
Sweating cools the body because
Which part of the skin absorbs ultraviolet light?
When you are cold, the hair erector muscles
Which part of the brain detects a change in blood temperature?
One harmful effect of skin-bleaching creams is that they
exam style · 4 marks
Explain how the skin helps to cool the body on a hot day.
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Practice questions are written by My V.I.P. Academy. They are not official CXC papers.