Page 35 - FOUNDATIONS FOR LIFE; EXPLORING GOD’S UNIVERSE

Science Y6 – Marvellous Me – lesson 3

Read the following then answer the questions.

Skin is a waterproof covering which is made up of many layers of tissues that guard the muscles and organs.
The surface of the skin, the epidermis, is made up of flat dead cells which are continually being replaced from
below. The body produces a new outer skin every 27 days. Dust we see at home is often made up of dead
human skin cells.

Below the epidermis is the dermis which is thickest on the palms of the hands and thinnest on the eyeballs. It
contains blood vessels, hair follicles, oil glands and nerve endings. The dermis also contains about 2.5 million
sweat glands.

Skin has several functions: -

 It protects the body from poisons, germs and water.
 It insulates the body
 It regulates the temperature in the body
 It is sensitive to touch, heat, light, etc
 It makes vitamin D.

The skin is often known as ‘the largest organ of the human body’. This applies to exterior surface, as it covers
the body, appearing to have the largest surface area of all the organs. Skin weighs more than any single
internal organ, accounting for up to 15% of body weight. For the average adult human, the skin has a surface
area of between 1½ - 2 square metres, most of it is between 2-3 mm thick. The average square centimetre of
skin holds around 300 sweat glands, 8 blood vessels, and 400 nerve endings.

Skin has colouring, or melanin, which absorbs some of the potentially dangerous ultraviolet radiation in sunlight.
Brown and black skins have plenty of melanin to protect people from the hot sun. Under the skin everyone’s
bodies have the same organs.

Mammalian skin often contains hairs which mainly serve to increase the insulation the skin provides.

Damaged skin will try to heal by forming scar tissue, often giving rise to discoloration of the skin.

1. Name the two outer layers of skin. _______________________ _______________________

2. What makes up much of the dust in our homes? ____________________________________________

__________________________________________________________________________________________________

__________________________________________________________________________________________________

3. How many sweat glands are contained in the dermis? _______________________

4. What are the main functions of the skin? ___________________________________________________

__________________________________________________________________________________________________

50