reflexes and pacinian corpuscle

Question 1

define reflex

Answer 1

a rapid response to a stimulus without using conscious control

Question 2

pathway of a stimulus

Answer 2

• stimulus detected by receptor
• receptor connected by synapse to sensory neuron
• sensory neurone connected to relay neuron via synapse
• relay neuron connected to motor neuron via synapse
• motor neuron connected to effector by synapse

Question 3

describe and explain what happens when a Pacinian Corpuscle is stimulated:

Answer 3

• pressure causes lamellae to stretch and deform
• so stretch mediated Na+ ion channels open
• Na+ diffuses into neurone
• the greater pressure, the more Na+ ion channels open
• this leads to slight depolarisation of the neurone (the generator potential)
• if the generator potential reaches threshold, an action potential is triggered