Synapses and Reflex Arc

Question 1

What are receptors?

Answer 1

Specialised cells that detect changes in the environment called stimuli

Question 2

Where are receptors found?

Answer 2

Eyes
Ears
Nose
Tongue
Skin

Question 3

What is each receptor sensitive to?

Answer 3

• Eyes - Light
• Ears- Sound and position of head
• Tongue- Chemicals in food
• Nose- Chemicals in the air
• Skin- Touch, pressure, pain and temperature

Question 4

What are the stages involved in a reflex action?

Answer 4

1. A stimulus is detected by receptors and impulses are sent along a sensory neurone to the CNS.
2. The impulses reach a synapse between the sensory neurone and the relay neurone and trigger chemicals to be released.
3. The chemicals cause impulses to be sent along the relay neurone.
4. Impulses reach a synapse between the relay neurone and the motor neurone and chemicals are released causing an impulse to be sent down the motor neurone
5. The impulses travel along the motor neurone to the effector (most of the time it is a muscle).

Question 5

What is a synapse?

Answer 5

The connection between two neurones

Question 6

How does a synapse work?

Answer 6

It transfers nerve signals using chemicals which diffuse across the gap

Question 7

What do the chemicals, released by a synapse, do?

Answer 7

Set off a new electrical signal in the next neurone