In this video we will look at the cranial nerves one by one and we'll look at a general overview. So let's begin by saying that we have 12 cranial nerves. In this video the nerve I will draw in blue will stand for sensory nerves and the red will represent motor nerves. So here is the inferior view of the brain. Let's begin with cranial nerve number one. So cranial nerve number one is an olfactory nerve which is a sensory nerve. It travels through the ethmoid bone and lays upon the cribriform plate and here the olfactory nerve actually it's sensory nerve and it will receive smelling senses from the nasal cavity and will send this information to the brain essentially. Cranial nerve number two is the optic nerve. These are also sensory nerves which receive signals from the retina and brings this vision info to the brain. Cranial nerve number three, known as the oculomotor nerve, arises from the midbrain and it is a motor nerve. It supplies most of the muscles of the eyeballs. These muscles are the inferior oblique, superior rectus, inferior rectus and medial rectus. The next nerve is the cranial nerve number four which is known as the trochlear nerve which arises from the midbrain. The trochlear nerve supplies one of these muscles as well, the eyeball muscles, the superior oblique that is. Then there is another cranial nerve which is 6, so we skipped 5, we're looking at 6, cranial nerve number 6, which arises from the pons. This cranial nerve number 6 is called the abducens nerve. It abduces as in. it abducts to take away. So the abducens nerve is a motor nerve for the lateral rectus muscle of the eye. So the cranial nerves, again, responsible for the movement of the eyeball are the cranial nerves 3, oculomotor nerve, cranial nerves 4, trochlear nerve, and cranial nerve number 6, which is the abducens nerve. And these are motor nerves. Before going on to the next cranial nerve, cranial nerve number three, the oculomotor nerve, has another important function in that it innervates the ciliary muscles of the eye. And thus, the oculomotor nerve has an important role in accommodation. The sensory nerve responsible for most of the face sensation is the next cranial nerve, which is cranial nerve number five, also known as a trigeminal nerve. It is a very big nerve and originates from the pons and the midbrain. The trigeminal nerve, it has three big branches which are sensory and these are known as V1 for ophthalmic nerve which senses this area of the face, V2 the maxillary nerve responsible for sensory in the maxilla area and V3 which is the mandibular nerve responsible for senses in the mandibular area. the jaw. The trigeminal nerve is a big nerve because it also does motor, so it does sensory and motor. It has motor nerves for the muscles of mastication, which are your temporal muscles, masseter, and the lateral and medial pterygoid muscles. These muscles of mastication are supplied by the V3 of the trigeminal nerve, which is the mandibular nerve branch. So we already talked about cranial nerve number six which was the abducens nerve and remember it abducts it supplies the lateral rectus muscle. The one after the abducens nerve is the facial nerve, cranial nerve number seven. It originates from the pons. The facial nerve as the name suggests supplies the face. It is an important nerve for the muscles of facial expression such as for your frontalis, your orbicularis oculi, your orbicularis oris, etc. The facial nerve also has special functions in that it supplies all the secretory glands in your face such as your sublingual and your submandibular glands as well as your tear glands, the lacrimal glands. The facial nerve however does not supply your parotid glands. It is supplied, the parotid glands, it is supplied by another cranial nerve which we'll talk about. The facial nerve however does pass through the parotid glands and so you have to be careful of the facial nerve when you're removing the parotid glands for some surgical reason. The facial nerve does taste of the anterior two-thirds of the tongue. So over all the facial nerve. The facial nerve does taste of the anterior two-thirds of the tongue. So overall, the facial nerve is a pretty big player with some mostly motor function. Cranial nerve number eight is the vestibulocochlear nerve which essentially is for hearing and it is made up of two nerves, the vestibular nerve which comes from the vestibule of the inner ear and the cochlear nerve which comes off the cochlea. They join and form the vestibulocochlear nerve which travels to the pons area of the brain. Cranial nerve number nine is the glossopharyngeal nerve. It originates from the medulla and it is motor for the parotid glands. It is also special sensory taste and normal sensory for pain and stuff for the posterior one third of the tongue. It is also sensory for the pharynx initiating the gag reflex. The glossopharyngeal nerve is also a motor for the gag reflex together with the next cranial nerve which is cranial nerve number 10. Cranial nerve number 10, which is your vagus nerve, is motor and sensory to many organs in your body, specifically the digestive organs. It originates from the medulla and it is responsible for stimulating the rest and digest response. So rest and digest response is the opposite of the fight or flight response, which is basically a sympathetic. So again, your cranial nerve, which is your vagus nerve, innervates smotor and it's sensory for most organs in your body. This includes the heart, the lungs, and your digestive system. It stimulates the rest and digest response. and not the sympathetic. So it opposes the sympathetic. The spinal accessory nerve is your cranial nerve number 11, and it originates from the medulla. It is a motor nerve for two important muscles, the SCM muscle and the trapezius. The last cranial nerve is the hypoglossal nerve, cranial nerve number 12, which originates from the medulla. And it is motor for the tongue, basically, the movement of the tongue. So that was an overall picture of the functions of the cranial nerves. Each of these cranial nerves, they do more than what I just said, but what I presented in the video was an overall picture. So hopefully that helped. Thank you for watching.