Nervous system (Qs 1-25 True/false)
1. The soma of neuron is resistant to hypoxia.
Ans: False. It is extremely vulnerable to hypoxia.
2. All nerve terminals can synthesize their own
neurotransmitters.
Ans: False .Peptides NTs are made in the cell body and
transported to the nerve terminals.
3. Plasticity in the adult CNS refers to the physical
realignment of fibers after injury or stress.
Ans: False.Plasticity is a functional adaptation of physical
linkages. Physical remodelling only occurs in the peripheral nervous system and
in the immature CNS.
4. Neurons are incapable of division.
Ans: True.
5. Neuro-neuronal synapses are either axo-dendritic or
axo-somatic.
Ans: False.Dendro-dendritic synapses are also found.
6. Neuroglia is derived from ectoderm.
Ans: True
7. Oligodendrocytes are the functional CNS counterparts of
Schwann cells.
Ans: True.needed for the formation and repair of myelin
sheaths.
8. Astrocytes are important in supplying omega-3 fatty acids
to nearby neurons in starvation.
Ans: False. Neurons do not use fatty acids for energy even
in starvation.
9. Astrocytes are believed to secrete K+ into the ECF of the
brain.
Ans; True
10. The nodes of Ranvier are present in all motor nerves.
Ans: False. Present only in myelinated nerves.
11. Extracts of the Japanese puffer fish abolish the
membrane potential.
Ans: False.Tetrodoxin blocks NA+ channels by blocking
initiation or propagation of the action potential.
12. There is an overlap between the specific receptors for
different modalities (pain, temperature, touch, vibration and pressure)
Ans: True.The specificity of receptors for individual
modalities is not now regarded as absolute.
13. Free nerve endings are only found in the skin and
surface epithelium.
Ans: False. In deeper tissue layers free nerve endings
innervate muscle spindles, vascular smooth muscle, and chemo sensitive cells
that subserve stretch and the local chemical environment.
14. All synaptic clefts have the same width.
Ans: False. Vary from about 20nm to as little as 2nm.
15. In the skeletal muscle endplate, IPSPs exceed EPSPs when
the muscle is at rest.
Ans: False.There is no IPSPs at the motorend plate.
16. Presynaptic inhibition is very important in damping down
visceral and somatic afferent activity in the spinal cord.
Ans: True
17. Postsynaptic inhibition occurs at Renshaw
cell/Renshawcell synapses.
Ans: True. [Alcohol stimulates Renshaw cells.
18. IPSPcauses hyperpolarisation in postsynaptic neuron.
Ans: True
19. In convergence large numbers of presynaptic neurons have
synaptic connections on a single postsynaptic neuron.
Ans: True
20. Fatigue that occurs at synapse is irreversible.
Ans: False
21. Receptors detecting changes in muscles length are
proprioceptors.
Ans: True
22. Paccnian corpuscles adapt very quickly.
Ans: True
23. Meissner’s corpuscles are abundant at finger tips.
Ans: True.
24. Merkel’s discs are slowly adapting receptors.
Ans: True
25. A Dermatome is a segmental field of skin innervated by
each spinal nerve
Ans: True.
