Receptors and Neurones

Question 1

What are the three types of neurones?

Answer 1

sensory, motor and relay neurones

Question 2

What is the role of sensory neurones?

Answer 2

to transmit nerve impulses from receptors to CNS

Question 3

What is the role of motor neurones?

Answer 3

transmit nerve impulses from CNS to effectors

Question 4

What is the role of a relay neurone?

Answer 4

join up sensory and motor neurones in the CNS

Question 5

Why are sensory neurones said to be transducers?

Answer 5

They convert the energy of the stimulus into electrical energy.

Question 6

Explain how a pacinian corpuscle works?

Answer 6

when pressure is applied to the pacinian corpuscle, it changes shape and stretches the membrane surrounding its neurone, so stretch mediated sodium ion channels open and sodium ions can diffuse into the neurone. Membrane is depolarised resulting in an action potential

Question 7

Explain how the resting potential of a neurone is maintained?

Answer 7

Outside of membrane is positively charged compared to inside. Due to sodium-potassium pump actively removing three sodium ions for every two potassium ions moved in. Also potassium ion channel lets potassium ions move out neurone via facilitated diffusion.

Question 8

What is the membrane of a neurone said to be?

Answer 8

polarised due to the difference in charge across it

Question 9

What is the resting potential value?

Answer 9

-70mV

Question 10

What is the sodium potassium pump?

Answer 10

an intrinsic protein