(a)[3]
Outline the functions of sensory receptor cells in the mammalian nervous system.
(b(i))[3]
State which of C, D and E on Fig. 8.1 matches each event below. You may use C, D or E once, more than once or not at all. The $\text{Na}^+/\text{K}^+$ pump is operating. The voltage-gated $\text{Na}^+$ channels are open. The voltage-gated $\text{K}^+$ channels are open.
(b(ii))[2]
Explain why stimulus A did not produce an action potential but stimulus B did.
(b(iii))[2]
Describe the importance of the refractory period in the transmission of action potentials.
(b(iv))[4]
Describe how action potentials are transmitted along a myelinated axon.