It is a good day to end the post on the cranial nerves but this isn't going to be the last post on this series. Neurology is a difficult one you will say, well it is fun to a reasonable extent. With the cranial nerve, you can understand why certain things happen. For instance, what is responsible for tasting, why does the eyeball move, what is responsible for the movement of the papillae, what is responsible for identifying speech in the brain, and what nucleus in the brain is accountable for giving interpretations to words heard? These, and a lot more is the reason why the cranial nerve is very important. Let me do a quick wrap-up of the entire cranial nerve, from the 1st to the 11th cranial nerve, which was the last I did before this.
I will start with the first cranial nerve which is the Olfactory Nerve, found in the root of the nasal cavity, supplying the nasal cavity (nose) through the olfactory foramina of the ethmoid bone to the olfactory bulb where it is taken to brain and allowing for smell cautiousness. The olfactory nerve is made of special visceral afferent fibres which help in olfaction (identifying smell). This nerve takes only sensory information, making it a sensory nerve. You can read more about the Olfactory nerve from the post Neurology Explained - The Olfactory nerve (Cranial Nerve 1) .
The Optic Nerve is the second cranial nerve. It has its origin in the Retina, and its picks information from the photoreceptors (Rods and Cones) in the retina, taking visual information through the optic canal to the optic chiasma, then to the ocipital lobe. They utilize the Special Sensory Afferent nerve fibers (SSA), which allows for vision. The Optic Nerve is a sensory nerve, and you can read more on the nerve in the post Neurology Explained - The Optic nerve (Cranial Nerve 2).
The Oculomotor Nerve is the third cranial nerve, and it has its origin located in the mid brain, at the level of the superior coniculus, and moves through the orbital fissure to its innervated tissues. The nerve supplies the superior rectus, the lavitor palpebra superiors, the inferior rectus, the Inferior Oblique, the sphincter pupillae, the ciliaris, and the medial rectus. The oculomotor nerve utilize the General Somatic Efferent, and the General Viscerla Efferent nerve fibers. The Oculomotor nerve is responsible for eye lid movement, eye movement, light accommodation in the lens, and pupil size. The Oculomotor nerve is a motor nerve. You can read about the Oculomotor nerve from the post Neurology Explained - The Oculomotor nerve (The Cranial Nerve 3).
The Trochlear Nerve, is the fourth cranial nerve, and it has its origin in the midbrain and it supplies the superior oblique. It utilizes the general somatic efferent nerve fiber and it controls the eye depression via the superior oblique. The Throchlear nerve is a motor nerve. You can read more on this from the post Neurology Explained - The Trochlear Nerve (The Fourth Cranial Nerve).
The Trigeminal nerve is the fifth cranial nerve, and its origin is located in the Pons, midbrain, and it has ganglion. The Trigeminal nerve nucleus includes the Principal pontine nucleus, the Mesencephalic nucleus, and the spinal nucleus, and the trigeminal motor nucleus. It supplies the palpebral, the skin of the scalp, the conjustiva, the skin of the ear, skin of the jaw, chin, nose, the oral cavity, the tensor tympani, the tongue, the muscle of masticulation, and the tensor of veli palatini. It utilizes the Special viseral Efferent fibers, and the General Somatic Afferent fibers. It helps for sensations of touch, pain, pressure and in the mouth mastication muscles innervation. You can read more about this in the post Neurology Explained - The Trigeminal Nerve (The Fifth Cranial Nerve)
The Abducens Nerve which is the sixth cranial nerve, is found in the inferior of the pons. It supplies the lateral rectus, and it utilizes the General Somatic Efferent fibers. It is responsible for the lateral rotation of the eye (Eye movement). The Abducens nerve is a motor nerve and it runs through the superior orbital fissure to the muscle it supplies. You can continue reading this from the post Neurology Explained - The Abducens Nerve (The Sixth Cranial Nerve)
It is important to know that the muscles of the eyes are innevated by the sixth, the fourth, and the third cranial nerve. The sixth cranial nerve innervates the Lateral Rectus, the fourth cranial nerve supplies the Superior Oblique, and the Third Cranial nerve innervates all other muscles of the eyes which includes the inferior rectus, superior rectus, lavator palpebral superiors, medial rectus, and the inferior oblique.
The Facial Nerve which is the seventh cranial nerve is found in the pons primarily and it has several nuclei. The facial nerve is a sensory and motor nerve which moves through the internal acoustic meatus, and the stylomastoid foramen into the pons medulla junction which is lateral to the abducens nerve, and medial to the vestibulocochlear nerve. The facial nerve supplies the facial expression muscles, the stapidius, the digastric muscles, the stylohyloid, the lacrimal glands, the nasal gland, the palentine glands, taste to the anterior two-third of the tongue, and supplying the tympanic membrane. The fibers supplying these locations are the Superior Visceral Efferent, the General Visceral Efferent, the Special Visceral Afferent, and the General Somatic Afferenr fiberes. The facial nerve controls the muscles of facial expression, lacrimation, for taste, and for sensation on the tympanic membrane. You can read more on this in the Neurology Explained - The Facial Nerve (The Seventh Cranial Nerve).
The Vestibulocochlear Nerve which is the eight cranial nerve. has its origin in the Pons Medulla Junction. It is made up of the vestibular branch and the Cochlear branch. The Vestibular branch supplies the vestibule, the semicircular canal, and the Cochlear branch supplies the Cochlea (the cochlea duct). The vestibulocochlear nerve utilizes the Special somatic afferent fiber. The vestibulocochlear nerve is responsible for dynamic equilibrium and balance, and sound. Vestibulocochlear nerve is a sensory nerve as well as a motor nerve but primarily a sensory nerve. You can read more about it in the post Neurology Explained - The Vestibulocochlear nerve (Cranial Nerve VIII) || The Cochlear (Auditory) Pathway, and the Neurology Explained - The Vestibulocochlear nerve (Cranial Nerve VIII) || The Vestibular Pathway
The Glossopharyngeal nerve which is the ninth cranial nerve has its origin in the medulla oblongata. It has several nuclei, and it supplies stylopharyngeus, the oral cavity, the posterior one-third of the tongue, the pharynx, the soft pallet, tonsils, inner tympanic membrane, external ear, the parotid gland, the carotid sinus, and the carotid branch. It utilizes the Special viseral efferent fibers, General visceral afferent fiber, General Somatic Afferent fibers, and General Visceral Efferent fiber. It helps to identify touch, pain, temperature senses in the ear, the soft pallet, the tongue, and elevate the pharynx. It is a Sensory and motor nerve. YOu can read more in my post Neurology Explained - The Glossopharyngeal nerve (Cranial Nerve IX)
The Vagus nerve which is the tenth cranial nerve is found in the medulla. It has several nuclei and irt supplies the pharynx, the larynx, the soft palate the heart, lungs, and the abdominal visceral (stomach, liver, esophagus, the gall bladder, the pancreas), the epiglottis, and the external ear. It utilizes the General Visceral Efferent fiber, Special viseral afferent fiber, General Somatic Afferent fibers, the Special viseral efferent fibers, and the General visceral afferent fiber. The Vagus nerve is the major parasympathetic nerve, responsible for the actions of major organs in the body. You can read more about the vagus nerve in my post Neurology Explained - The Vagus nerve (Cranial Nerve X)
The Accessory nerve which is the eleventh cranial nerve has the cranial part origin primarily in the medulla, and the spinal part in the cervical spinal cord within the C1 to C5 of the spinal cord. It supplies the Trapezius muscle, and the sternocleidomastoid muscle. allowing for the flexion of the neck and the movement of the scapula. The fibers utilized are the General Somatic Efferent fibers, and the Special viseral efferent fibers. It is a motor nerve and you can read more about this in my post Neurology Explained - The Accessory nerve (Cranial Nerve XI).
Conclusion
After explaining the cranial nerves from the first to the eleventh, you will understand the locations the nerves innervates and the origin of the cranial nerves. In my next post, I will be writing the last cranial nerve, which is the 12th cranial nerve.
Image 1 || Wikimedia Commons || Brain human normal inferior view with labels