1What are receptors?
Cells that detect stimuli
2What does it mean that receptors are specific?
Each type of receptor detects a different type of stimulus
3What types of stimuli can touch receptors in the skin detect?
Light pressure, deep pressure, sustained pressure, temperature and pain
4What are Pacinian corpuscles?
A type of receptor found deep in the skin that responds to changes in pressure
5Where are Pacinian corpuscles found?
At the sensory neurone endings deep in the skin
6What are Pacinian corpuscles made of?
Many layers of membrane separated by gel
7What are the membrane layers in Pacinian corpuscles sometimes called?
Connective tissue or lamellae
8What is a generator potential?
A change in the potential difference across the membrane of a nerve cell in response to a stimulus
9What determines the size of a generator potential?
The size of the stimulus
10What happens if a generator potential is large enough?
It initiates a nerve impulse or action potential
11Where do generator potentials occur?
Only at the site of the stimulus
12How do generator potentials vary?
Their size differs depending on the size of the stimulus
13What can generator potentials lead to?
An action potential
14What happens to Pacinian corpuscles when pressure is applied to the skin?
The layers of membrane are distorted
15What type of sodium channels open when Pacinian corpuscles are stimulated by pressure?
Stretch-mediated sodium channels
16How do sodium ions enter the axon during Pacinian corpuscle stimulation?
Through facilitated diffusion
17What effect do sodium ions entering the axon have?
They make the inside of the axon more positive, creating a generator potential