U5 B7 1HVTTO

• Biologie
• Middelbare school
• havo, vwo
• Leerjaar 1

B7 Senses and impulses

• Take off your jacket
• Put your things on your desk

       Book, notebook, pencil case

• Bag on the floor
  
• Read pages 136-137

Lessongoals

• You can explain when senses convert stimuli into nerve impulses
• You can name the structure and function of three types of nerve cells

Taste is an important part of food. But often the texture of food also plays a big role in people liking or disliking food.
What sense in the mouth perceives this part of food?

A scientist is looking at a piece of the skin of an animal, he researches the different layers of the skin.
Which of the senses (in sensory organs) will he probably find first when he start on the outside of the skin and moves further inwards?

1. sense of pain
2. sense of heat
3. sense of cold
4. sense of pressure

Leprosy is an illness in which bacteria infect the nerves in the skin. This results in people with leprosy losing their ability to feel things.
Explain why leprosy has this effect on their ability to feel

Why can't humans hear certain sounds, but dogs can?

Types of stimuli

• Some stimuli are too weak, beneath the threshold value of the sensory organ: you don't notice them
• Adequate stimulus = stimulus belonging to a sensory organ, low threshold value
• Stronger stimulus > higher amount of impulses = higher impulse frequency

Why don't you feel your clothes all day?

Reacting to stimuli

• Habituation: used to stimuli > higher threshold value. You won't notice it (as much)
• Motivation: your brains change the threshold value 
• Influencing: your brains change the image created, because they are influenced.

Na een tijdje kleren dragen, merk je dat niet meer.

Als je goed oplet, wordt drempelwaarde van je gehoor lager. je hoort net wat beter

Bij gezichtsbedrog worden de hersenen voor de gek gehouden

sensory neuron

• passes impulses from sensory organ to central nervous system
• cell body outside of central nervous system

S

interneuron

• Passes impulses from other nerve cells
• No long axons
• Only found inside central nervous system

I

motor neuron

• Passes impulses from central nervous system to muscle/gland
• Cell body on the end in the central nervous system

M

Types of nerve cell

In this situation, for the person indicated with the arrow.
What type of nerve cell will act first?

1. Motor neuron
2. Sensory neuron
3. Interneuron

In this situation, for the person indicated with the arrow.
What type of nerve cell will act first?

1. Motor neuron
2. Sensory neuron
3. Interneuron

What you should do:

• Read pages  13-137
• Do asgmt  1-5, 6c pgs. 138-139

Done with the above?

• Work on the next chapter(s)
• Learn for the test 
• Make other homework
• Read a book

Zs = Working in Silence

• No asking questions
• Silent, don't disturb anyone
  
• Stay at your  desk

What you should do:

• Read pages 13-137
  
• Do asgmt 1-5, 6c pgs. 138-139

Done with the above?

• Work on the next chapter(s)
• Learn for the test 
• Make other homework
• Read a book

Zw = Working with whispering

• Teacher is available for questions
• Only whisper with the student next to you
• Stay at your  desk

Tidy Duty

Today these people are on tidy duty

• Desks: empty and straight
• Chairs:  underneath the desks
• Floor: no rubbish