In: Biology
Which of these attributes are similar between the visual and somatosensory systems?
a. All axons that carry information from the periphery are myelinated
b. All of these answers are correct
c. Topographical organization
d. Peripheral information reaches the cortex via the LGN
e. Peripheral receptors depolarize in response to environmental stimuli.
Correct Answer is ( C) and ( E).
Explanation:
1. Ordered topography means that there is ordered projection of sensory surface ( eg skin or retina ) to one or more structured of CNS . This is present in both pathways.
2.Peripheral receptors depolarize in response to environmental stimuli is true. Peripheral receptors can be either a Free nerve endings or an encapsulated ending ( as in somatosensory system ) or can be a specialized receptor cell ( a photoreceptor, in the visual pathway ).
3. All axons carrying sensations are not myelinated. Afferent fibers conducting impulse from peripheral sensory organs are type C fibers which are non- myelinated.
Intraocular part of the Optic nerve is also non-myelinated. Myelination is seen in optic nerve after it exits from lamina cribrosa.
4. Peripheral information reaches cortex via LGN ( Lateral Geneculate Nucleus ) in the thalamus is true for visual pathway. But somatosensory fibers relay in posterolateral ventral nucleus of the thalamus.