Q. Which cranial nerves are purely sensory?
Solution:
Those nerves arise from the brain are called cranial nerves and they are 12 in number. They pass-through various foramina in the bones of the cranium. It divides into three parts on the basis of the function i.e. sensory, motor, and mixed nerves. The name of the twelve nerves are mentioned below:
1.Olfactory nerve (I) 2.Optic nerve (II) 3.Occumulator nerve(III) 4.Trochlear nerve (IV) 5.Trigeminal nerve (V) 6.Abducens nerve (VI) 7.Facial nerve (VII) 8.Vestibulocochlear nerve (VIII) 9.Glossopharyngeal nerve (IX) 10.Vagus nerve (X) 11. Acessory nerve (XI) 12.The hypoglossal nerve (XII)
III, IV, V, VI, X, XI, XII are motor nerves. VII, IX are mixed nerves
I, II, V, and VIII are cranial nerves in which the olfactory nerve(I) contains axons that conduct impulses for olfaction, the sense of smell. The origin of the olfactory nerve is olfactory receptor nerve cells and opens in the cribriform plate of the ethmoid.
Optic nerve(II) contains axons that conduct nerve impulses for vision. The origin of the optic nerve in the back of the eyeball and opens into the optic canal. The vestibulocochlear nerve is VIII sensory nerve that has two branches i.e. vestibular branches and cochlear branches. The origin of the vestibulocochlear nerve is medulla oblongata and it opens into the internal acoustic meatus. It is an auditory nerve. The vestibular branch carries impulses for equilibrium and the cochlear branch carries impulses for hearing.
1.Olfactory nerve (I) 2.Optic nerve (II) 3.Occumulator nerve(III) 4.Trochlear nerve (IV) 5.Trigeminal nerve (V) 6.Abducens nerve (VI) 7.Facial nerve (VII) 8.Vestibulocochlear nerve (VIII) 9.Glossopharyngeal nerve (IX) 10.Vagus nerve (X) 11. Acessory nerve (XI) 12.The hypoglossal nerve (XII)
III, IV, V, VI, X, XI, XII are motor nerves. VII, IX are mixed nerves
I, II, V, and VIII are cranial nerves in which the olfactory nerve(I) contains axons that conduct impulses for olfaction, the sense of smell. The origin of the olfactory nerve is olfactory receptor nerve cells and opens in the cribriform plate of the ethmoid.