8 - HABITUATION

Question 1

What is habituation?

Answer 1

The reduced response to an unimportant stimulus after repeated exposure over time.

Question 2

Why does it happen?

Answer 2

Effectors that carry out the response to different stimuli are controlled by nervous stimulation. Habituation to a stimulus means that fewer electrical impulses are sent to the effectors.

Question 3

How does it happen?

Answer 3

1) Repeated exposure to a stimulus decreases the amount of calcium ions that enter the presynaptic neurone.
2) This decrease in the influx of calcium ions meant that less neurotransmitter is released from vesicles into the synaptic cleft, so fewer neurotransmitters can bind to receptors in the postsynaptic membrane
3) Fewer sodium ion channels on the postsynaptic membrane open - so there is a reduced chance of the threshold for an action potential being reached on the postsynaptic membrane
4) as a result, fewer signals are sent to the effector to carry out the response