B&S LESSON 2

• Biologie
• Middelbare school
• havo
• Leerjaar 2

HAVE READY

- HW FOR LESSON 2 UPLOADED

- YOUR NOTES

- KERBOODLE PAGE 110

- LESSON UP

HW FOR TODAY:

ANY PROBLEMS?

CEREBELLUM

CEREBRUM

MEDULLA

THALAMUS

MOST IMPORTANT STEPS OF THIS CHAPTER:

coordinator

effector

stimuli

receptor

response

MOST IMPORTANT STEPS OF THIS CHAPTER:

stimuli --> receptor --> coordinator --> effector --> respons

Dendrite

Cell body

Nucleus

Axon

Fatty sheath

Synapse

Synapses 

• Gap between 2 neurons
• When an impulse reaches the end of the axon it produces  a chemical: neurotransmitters
• Diffuses across the gap and binds receptors of in the membrane of the next neuron
• It starts off a impulse in the next neuron
• One end can make it so impulses travel in one direction!

Impulse

Impulse

Synapses 

2 other functions:

• Resistor: enough impulses are needed to start an impulse at the next neuron. 
• Junction box: a neuron can pass an impulse to a number of neurons

Drugs affect synapses

• Alchohol (slows reactions down)

Impulse

Impulse

Synapse at the muscle

Reflex arcs

• You take away your hand from an hot object very fast
  Automatically, why? 
  
  
• Reflexes protect you 
• Why do you think a reflex is unconscious? 
  
  
• Signal does not go to the brain immediately
• It goes to the spinal cord and back (short circuit) 

Reflex arcs

W

Stimulus? 

Receptor? 

Coordinator?

Effector? 

Response? 

Reflex arcs

Stimulus = hot flame 

Receptor = heat sensor in the skin

Coordinator = spinal cord 

Effector = muscles in your arm

Response = moving your hand away from the hot object. 

Which will receive a message by motor neurons?

1. Receptors in your skin
2. The spinal cord
3. The muscles in your arm
4. The brain

Which will send a message along sensory neurons?

1. Receptors in your skin
2. The spinal cord
3. The muscles in your arm
4. The brain

You get an itch in your elbow. What is the receptor in this reaction?

1. Receptors in your skin
2. The itch itself
3. muscles that move your arm to scratch
4. The brain that decides to scratch the elbow

You get an itch in your elbow. What is the coordinator in this reaction?

1. Receptors in your skin
2. The itch itself
3. muscles that move your arm to scratch
4. The brain that decides to scratch the elbow

You get an itch in your elbow. What is the response in this reaction?

1. Receptors in your skin
2. The itch itself
3. muscles that move your arm to scratch
4. The brain that decides to scratch the elbow

You get an itch in your elbow. What is the stimulus in this reaction?

1. Receptors in your skin
2. The itch itself
3. muscles that move your arm to scratch
4. The brain that decides to scratch the elbow

HW FOR LESSON 3:

- do the worksheets on classroom

- answer in a google docs

hand this in on classroom please.