Hi, welcome to class, in this lecture, will we begin our exploration of medical terminology as it relates to the sensory system and in particular the eye and the ear, let's get started. The function of the sensory system is to collect details about the surroundings and send that information onto the central nervous system. The branches of medicine that specialize in the vision and hearing portions of the sensory system are called ophthalmology and otolaryngology, respectively. Let's begin by looking at the eye. Wait, can one look at one's own I perhaps in a mirror. We'll just stick to its purpose and new word roots. But first, let's look at this adorable baby kitty cat. Whoa! That's a wild kitty cat. The major function of the eye is to provide sight. It is protected by the bones of the skull. Teenagers often forget the main purpose of the eye and instead choose to use them to express just how much they appreciate all the wisdom so lovingly imparted by their elders. Although I'm sure you never did that. Such angels, there are multiple word roots that all mean eye. They include ocul/o, ophthalm/o, opt/o and you can find them in words like ophthalmologist and optometrist, tears are designed to keep the eyes moist. They are produced by lacrim/o the gland located superior to the eye. As you can see in the name of the lacrim/o gland. Both lacrim/o and dacry/o mean tear the tears flow across the surface of the eye and are collected by the lacrim/o duct the tears are then drained into the nose. That's right, the tears are drained into the nose. That's why when you ugly cry, you also snot. Or if you're trying to pretend that you're an adult now and that Disney movies don't affect you anymore and attempt to suck up that tear in your eye. It just drips out your nose. If you don't let them come out of your eyes or nose and you try to sniff them back in, they go into your throat one way or another they're coming out. Everything's connected people. Blephar/o is the word root for eyelid, eyelids protect the eyes from dust and other floating particles in the air. And help to keep the eye moist and they help to keep that eyeball firmly in the socket when you sneeze. Thank goodness. The outermost layer of the eye is made up of sclera and the cornea, the sclera is the white of the eye sclerosis is the root for sclera. The cornea is clear and covers the front portion of the eye, corne/o and kerat/o both mean cornea. Fun fact the cornea contains no blood vessels, that's right. Zero zippo none. And you can have a cornea transplant. Perhaps consider donating yours when you're done with them to give someone else the gift of sight. You can have mine but not yet. The conjunctivitis lines the upper and lower eyelids and most of the surface of the eye. It is a loose connective tissue that covers the surface of the eyeball and then reflects back upon itself to form the inner layer of the eyelid. When you get of your conjunctivitis, it is called conjunctivitis or as it is more commonly known, Pinkeye. The highly contagious disease causes an inflammation of your conjunctivitis with the characteristic pink that develops over the sclera along with a yellow discharge. But don't worry, it's easily treated with antibacterial eyedrops. Unless your kids hate having eyedrops put in their eye then it might not be quite so easily treated. But don't give up your bigger, stronger and smarter than they are maybe. Although we have been looking at the root specific to the eye. There are also two suffixes unique to vision. -Opia and -opsia. Both meaning vision. They can be seen in words like hyper -opia or farsightedness and taking a -opsia or an inability to see a moving object. And now for a 10 second brain break. [MUSIC] That's better continuing our discussion of the sensory system. We will now move from the eye to the ear. Did you know that ears are completely individual just like fingerprints, they are. Some people have even explored technology that would unlock a cell phone when held to the ear just by recognizing its unique pattern, fun. The main purpose of the ear is hearing. What? Hearing. What I said. The main purpose of the ear is hearing. You heard me the first time the ears collect sound waves which in turn vibrate structures within the ear. The vibrations are changed into electrical signals within nerves. The acoustic nerve sends these electrical signals to the brain. The brain interprets these signals as sound. The air itself can be subdivided into the outer middle and inner ear. We will look at the main components of each of the subdivisions next. The outer ear includes the pinna and the ear canal. The pen is what most people think of when they think about the ear, the fleshy outside portion which sits on the mastoid bone of the skull. The pinna is shaped like a funnel which helps collect sounds from the air and send them down through the ear canal. Round and round they go into the middle ear. Speaking of cleaning your ears. Cerumin/o is the word root for earwax and cerumin as the medical term for earwax. Like this little treat that someone removed from an ear. >> [INAUDIBLE] >> The tympanic membrane or eardrum separates the outer ear from the middle ear. The word roots associated with the tympanic membrane are tympan/o and myring/o. Has anybody else ever seen or experienced a ruptured eardrum? I have, a perforated ear drum. May be caused by loud sounds, a foreign object in the ear, head trauma, a middle ear infection or rapid pressure changes such as from air travel. Symptoms include sharp ear pain that subsides quickly drainage ringing in the ear or hearing loss. The condition usually heals on its own within a few weeks. Mine did, the middle ear is a hollow space between the outer and inner ear. It contains three tiny bones known as the auditory ossicles that carry the vibration of the tympanic membrane to the inner ear. The malleus Incus and stapes are also called the hammer, anvil and stirrup because of their shape. It's a nickname. The inner ear begins with the entrance to the cochlea. The cochlea is a bony shell filled with fluid and hair. When sound waves are transferred to the fluid within the cochlea, the fluid moves and vibrates tiny hairs attached to a membrane. The tiny hairs vibrate, creating electrical signals that then traveled down the acoustic nerve to the brain. The cochlea is also called the snail because it looks like a door, just kidding, looks like a snail. The inner ear is also involved in the interpretation of balance and direction as part of the vestibular system, vestibular literally means a vestibular entryway. Here, the vestibule is a small area in front of the semicircular canals, which help regulate balance. These semicircular canals are filled with fluid and hair. Unlike in the cochlea, the hairs in the vestibular system are moved by movement and head angle rather than sound. This allows them to send information to the brain about the tilt rotation and motion of the head as well as your orientation in space. It also allows the brain to coordinate movement with the eyes. Because the hairs in your inner ear respond to gravitational pull, your vestibular system can also help orient you to gravity. This can become particularly important if you're ever caught in an avalanche. We get a lot of those here in hot, humid Houston theoretically though, if you remain calm when trapped beneath a mountain of snow. Your inner ear will help you determine which way is up so that you don't accidentally dig yourself into an even deeper hole. As with all good things, this lecture, too, must come to an end. Thanks for exploring introductory terms and rates related to the sensory system with me. See you next time.
