I: | Myelinated nerve fibres |
II: | Unmyelinated nerve fibres |
I: | Hind brain and midbrain make up the brain stem. |
II: | The hindbrain comprises pons, cerebellum and medulla. |
III: | The forebrain consists of cerebrum, thalamus and hypothalamus. |
Statement I: | Depolarisation of axonal membrane is due to influx of sodium ions. |
Statement II: | Repolarisation of axonal membrane is due to efflux of sodium ions. |
Assertion(A): | The resting axonal membrane is more permeable to potassium ions than sodium ions |
Reason(R): | Potassium is the principal cation in the intracellular fluid. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False and (R) is True. |
1. | Diffusion of sodium to the inside of the cell. |
2. | Diffusion of sodium to the outside of the cell. |
3. | Diffusion of potassium to the outside of the cell. |
4. | Diffusion of potassium to the inside of the cell. |