5.4 The nervous system

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

What happens in the image on the left?

What is the adequate stimulus for the sense of seeing?

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

1. Central nervous system (CNS) = Brain and spinal cord

2. Periferal nervous system (PNS) = Nerves

How does the nervous system work?

Sensory cell receive stimulus from outside (ex. chocolate)

Sensory cells                                                                                                                         = impulses                              nerves   

      brain    

   muscles

Path taken by nerve impulses

2 types of pathways

  1. Conscious reaction - voluntary response, example: girl and   chocolate

  2. Reflex - involuntary response, impulse does not go to the     brain but stays within the spinal cord

 example: withdrawal reflex = hand touches fire 

Nerve cell

Structure of the nerve cell 

1. Cell body - located near the CNS

2. Axon - conducts impulses from cell body

The impuls 'travels'

What is a nerve?

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

Unit 5 basic 4 the nervous system

Do all knowledge questions and 2 insight questions of your own choice.