Q. No.When a neuron is resting, the axonal membrane is relatively more permeable to potassium ions and nearly impermeable to sodium ions. This would mean that:
1. in resting conditions, all sodium channels in the axonal membrane are closed while few potassium channels are open
2. in resting conditions, the electrogenic sodium-potassium pump will pump only the sodium ions
3. in resting conditions, the electrogenic sodium-potassium pump will pump only the potassium ions
4. in resting conditions, the outer surface of the axonal membrane will carry a negative charge
When an impulse arrives at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane. This activation of the synaptic vesicle is directly due to:
| 1. | Sodium ions | 2. | Calcium ions |
| 3. | Potassium ions | 4. | Chloride ions |
A canal called the cerebral aqueduct passes through the midbrain. This canal connects:
1. The two lateral ventricle
2. The lateral ventricles and the third ventricle
3. The third and the fourth ventricle
4. The fourth ventricle and the central canal of the spinal cord
The neurons of the olfactory epithelium extend from the outside environment directly into olfactory lobes. The olfactory lobes are the extensions of:
| 1. | Pre-frontal cortex | 2. | Corpus callosum |
| 3. | Corpora quadrigemina | 4. | Limbic system |
Identify the correct statement:
1. Sympathetic neural system is excitatory to the heart and inhibitory to the gut
2. Sympathetic neural system is inhibitory to the heart and excitatory to the gut
3. Sympathetic neural system is excitatory to the heart and to the gut
4. Sympathetic neural system is inhibitory to the heart and to the gut
Consider the following statements:
| I: | Impulses travel by the visceral nervous system from the CNS to the viscera and from the viscera to the CNS. |
| II: | Impulses travel by the autonomic nervous system from the CNS to the involuntary organs and smooth muscles of the body. |
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
Identify the correct statement:
| 1. | Unmyelinated neurons in PNS are not surrounded by Schwann cell |
| 2. | Electrical synapses, being faster, are more common in the human body |
| 3. | Pia mater is in contact with the brain tissue |
| 4. | The entire hindbrain and the midbrain constitute the brain stem |
Identify the incorrect match:
| 1. | Reticular formation | Gatekeeper to consciousness |
| 2. | Thalamus | Major relay centre in diencephalon for messages to the cortex |
| 3. | Superior colliculi | Part of limbic system for emotional behaviour |
| 4. | Pons | Part of hindbrain having nuclei for control of breathing rate |
| I: | When a neuron is not conducting any impulse, i.e., resting, the axonal membrane is comparatively more permeable to potassium ions (K+ ) and nearly impermeable to sodium ions (Na+). |
| II: | Similarly, the membrane is permeable to negatively charged proteins present in the axoplasm. |
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
| I: | is a part of the brain stem |
| II: | is a part of the hind brain |
| III: | is a part of the limbic system |
| 1. | Only I and II | 2. | Only I and III |
| 3. | Only II and III | 4. | I, II and III |
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