5.4 The nervous system

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

Today's planning

start with the nervous system 

What does a sensory cell produce once it picks up a stimulus?

What do we call the lowest intensity that can cause an impuls?

1. Adequate stimulus
2. Threshold value
3. impuls
4. habituation

If a stimulus does not go away for some time, it starts producing less impulses in the cell. What do we call this?

1. Adequate stimulus
2. Threshold value
3. impuls
4. habituation

Bs 4 The nervous system

• You must be able to name the functions of the nervous system. 
• You must be able to describe the structure of a nerve cell and a nerve. 
• You must be able describe the three types of nerve cells. 

Structure of the nervous system

Central nervous system

= In the centre

= brain + spine

Nerves

connect the CNS with all muscles and senses

How does the nervous system work?

Path taken by nerve impulses

2 types of pathways:

  1. Conscious reaction - voluntary response, example: girl and   chocolate (YOU choose to do something)

  2. Reflex - involuntary response, impulse does not go to the     brain but stays within the CNS. example: withdrawal reflex = hand touches fire  (your body does something without you choosing to do it)

Nerve cell

axon

Dendrite + cell body

receives the impuls 

From senses or nerve cells

Axon

Sends the impuls

 To the next nerve cell

Dendrite

Schwann cell

Protect the axon of nervous cells

Schwann cells wrap around axons 

to keep them safe, 

help impulses move faster, 

and can even help repair damage. 

Make 

Learnbeat sense

B: the nervous system

Only page 1 and 2. 

1. Moter neuron
2. Sensory neuron
3. Interneurons

1. Moter neuron
2. Sensory neuron
3. Interneurons

1. Moter neuron
2. Sensory neuron
3. Interneurons

What is a nerve?

Notes: 

nerve = a bundle of axons of nerve cells surrounded by a tough, protective layer

Motor neuron

Interneuron

Sensory neuron

carries impulses inside the central nervous system

carries impulses from central nervous system to muscles or glands

receives impulses from sensory neurons or interneurons

Receives impulses from interneurons

receives impulses from sensory cells

brings impulses to the central nervous system

Make the worksheet in studiewijzer

You may work alone or in pairs. 

If you work together, you both fill in the worksheet.

Learnbeat, Make 2:

B nervous system

 

Homework: worksheet nerves & nerve cells

• You must be able to name the functions of the nervous system. 
• You must be able to describe the structure of a nerve cell and a nerve. 
• You must be able describe the three types of nerve cells.