5.2 Touch

• Biologie
• Middelbare school
• vwo
• Leerjaar 1

Planning for today

• Quiz to see what you remember
• Bs 2: sense of touch
• Touch experiment

Learning goals

•  You can describe the structure and functions of the skin.

All your senses together form the ...

1. nervous system
2. sensory system
3. brain system
4. sense canal

Sense organs send signals through the nerves to the ...

1. eyes
2. ears
3. brain
4. muscles

How do you call the signals the sense organs send out?

1

5

4

6

2

3

10

Muscle 

 Axon

Sensory cells

Interneuron 

 Sensory neuron

Motor neuron

central nervous system

Senses of humans

The skin

• The skin is our biggest organ. 

• Our skin protects us against harmful things from outside, ex. viruses. 

• The skin of the average adult weights about 20 kg. 

Does anybody know how and why people have different colors of skin?

The epidermis

Notes

The skin is made up of two parts:

•  Corneal layer: 

-Consists of dead cells

-Protects your body against damage, dehydration and pathogens (bacteria)

•  Basal layer:

-Consists of living cells.

-New cells are made by dividing(deling) of cells.

-Top layer produces a lot of keratine.

Dermis

Notes

This is where the receptor cells of the senses in our skin are located. (heat, touch, cold)

The receptor cells for the sense of pressure are found deeper in the skin.

You can also find some glands (klieren)  here. Why do you think we sweat?

The corneal layer consists of dead cells

1. True
2. False

The sense receptors are located in
the basal layer

1. True
2. False

The basal layer makes new cells by
dividing of cells

1. True
2. False

Experiment touch receptors (15 min)

• Work in groups of 3
• Touch the test subject’s skin with the two compass points at the same time. Do that in three places: the pad of the index finger, the forearm and the tip of the nose.
• Each time the test subject is touched, they say whether they feel one or two points. Write down the observations of the test subject in the table.
• Repeat with every distance.

Homework

5.2: Touch

Ex. 1,2,3 abc