receptors exam qs

Question 1

Multiple sclerosis is a disease in which parts of the myelin sheaths surrounding neurones
are destroyed. Explain how this results in slower responses to stimuli.

Answer 1

Less saltatory conduction
2. More depolarisation across the whole length of the membrane

Question 2

an image formed at X is perceived in more detail than an image formed at Z

Answer 2

X has more cones than Z;
no retinal convergence

Question 3

In this investigation, it is not possible for a student to react in less than 45 ms
Suggest one explanation for the value recorded in Trial 3 in Table 1.

Answer 3

The student started to move her hand before the ruler was released;

Question 4

Suggest three reasons why, in this investigation, the estimated speed of student A’s
impulse transmission was less than 76.2 m s–1

Answer 4

1 - Time for synaptic transmission
2. Time taken for muscles to contract;
3. Time taken for sodium ion channels to open