Context
SCIENCE/ Sense organs
Jokers of interest
„live-drawing“
Materials
Big empty
poster
Red and
black markers
A rope
LESSON
Today we are going to talk about our
biggest organ. What is our biggest organ? It is a sense organ as well!
It´s the
skin.
How big is your skin?
If we could
take it off and put it on the floor like a cloth, it would cover 2qm.
(We spread
2qm with a rope)
If we could
crumple it up and weigh it, my skin would weigh 6kg.
(More than
a 5L water container filled with water!)
I take a big empty poster paper and start “live-drawing” a sketch of the structure of the skin,
doing this I am telling “the story of the skin”:
·
Epidermis: the outer layer of the skin is as
thick as a page, it´s a layer of dead cells. It protects other layers.
·
Leather
skin: The leather
skin is flexible/elastic, so that we can move our body freely.
The roots of the arm hairs sit in the leather skin. The hairs´ muscles contract when we feel cold, this sets the hair upright to build an extra protective layer: to keep warm. This also produces goosepimples (Chichewa=tsembwe)!
When it´s cold, the sweat pores close to keep the warmth safe inside. But when it is hot the skin pores open to release sweat and heat.
Sensory cells (Chichewa=mitsempha) : There are 4 main types of sensory cells, sensitive to (a) pain (b) pressure or touch, (c) cold, (d) heat. The sensory cells sent their informations to the brain
Some areas of the body are more sensitive than others, because the skin contains more sensory cells: The tips of our fingers are more sensitive to touch than the back of our hands. We are also ticklish in that sensitive areas!
The roots of the arm hairs sit in the leather skin. The hairs´ muscles contract when we feel cold, this sets the hair upright to build an extra protective layer: to keep warm. This also produces goosepimples (Chichewa=tsembwe)!
When it´s cold, the sweat pores close to keep the warmth safe inside. But when it is hot the skin pores open to release sweat and heat.
Sensory cells (Chichewa=mitsempha) : There are 4 main types of sensory cells, sensitive to (a) pain (b) pressure or touch, (c) cold, (d) heat. The sensory cells sent their informations to the brain
Some areas of the body are more sensitive than others, because the skin contains more sensory cells: The tips of our fingers are more sensitive to touch than the back of our hands. We are also ticklish in that sensitive areas!
·
Fat
and connective tissue (vocabulary help: tissue like toilet tissue!) keeps warm and
stores our body´s energy. Big blood vessels transport our blood
Summary notes
Functions
of the skin
We can
detect pain, coldness and hotness, touch and pressure.
We use our skin for…
- Detecting the roughness or
softness of surfaces
- Warning device (pain)
- To control our body temperature
- To prevent germs and water from entering the body
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