Q. No.The transmission of nerve impulses at a synapse is unidirectional.
Which of the features of the transmission of nerve impulses given below have a role in maintaining the unidirectional transmission?
1 Exocytosis of neurotransmitter at the presynaptic membrane
2 Neurotransmitter hydrolyzing enzyme found on the postsynaptic membrane
3 Neurotransmitter receptors found on the postsynaptic membrane
4 Sodium gated channels on the postsynaptic membrane
1. 2 and 4 only
2. 1, 2 and 3 only
3. 1, 3 and 4 only
4. 1 and 4 only
Which of the examples of homeostasis do NOT require the brain to be involved in the control process?
a. temperature regulation
b. osmoregulation (regulation of the water content of blood)
c. blood glucose concentration regulation
1. b and c only
2. c only
3. a and b only
4. b only
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 |
Consider the two statements:
| I. | The retina contains three layers of cells - from outside to inside – ganglion cells, bipolar cells, and photoreceptor cells. |
| II. | The macula of the semicircular canals and the crista of saccule and utricle are receptors of the vestibular apparatus. |
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
| 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
| A | B | C | D | |
| 1. | Muscle spindle | Motor end plate | Afferent pathway | Efferent pathway |
| 2. | Muscle spindle | Motor end plate | Efferent pathway | Afferent pathway |
| 3 | Motor end plate | Muscle spindle | Efferent pathway | Afferent pathway |
| 4. | Motor end plate | Muscle spindle | Afferent pathway | Efferent pathway |
| 1. | A | Major refractory surface |
| 2. | B | Accommodation |
| 3. | C | Regulates diameter of pupil |
| 4. | D | Point of highest visual acuity |
| I: | In a neuron, Nissl’s granules are present in dendrites as well as cell body |
| II: | Unmyelinated neurons in peripheral neural system are not enclosed by a Schwann cell |
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
| 1. | Medulla oblongata | Gastric secretions |
| 2. | Hypothalamus | Control of body temperature |
| 3. | Limbic system | Behaviour |
| 4. | Association areas | Purely sensory areas in the cerebrum |
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