Common Word Roots for Sensory System (Part 1)

acoust/o, acous/o or audi/o is a combining form that refers to "sound" or "hearing". Hearing, or auditory perception, refers to the ability to perceive sounds through a sensory organ, such as the ear, by detecting periodic changes in pressure.

chori/o or choroid/o is a combining form that refers to "choroid". The choroid forms part of the uvea, the eye's vascular layer, containing connective tissues and lying between the retina and sclera. The choroid supplies nutrients and oxygen to the outer retina.

cochle/o is a combining form that refers to "cochlea". In the inner ear, the cochlea is a hollow snail-like bone that is crucial for auditory transduction and essential for hearing. Sound is picked up by the cochlea through vibrations, which cause the stereocilia to vibrate. Upon receiving these vibrations, the stereocilia convert them into nerve impulses that can be interpreted by the brain.

conjunctiv/o is a combining form that refers to "conjunctiva". A transparent, thin tissue covering the outer surface of the eye called the conjunctiva. By secreting mucus and tears, the conjunctiva of the eye lubricates and protects the eye. In addition to protecting against microbes from invading, it also plays a role in maintaining immunity.

corne/o or kerat/o is a combining form that refers to "cornea". The cornea is the transparent portion of the eye that protects the iris and the pupil, as well as allowing light to enter the inner chamber of the eye.

cycl/o is a combining form that refers to "ciliary body" or "ciliary muscle". A ciliary body is a circular structure that is attached to the iris, the colored part of the eye. Fluid called aqueous humor is produced by the ciliary body in the eye. In addition, it contains the ciliary muscle, which changes the shape of the lens when you focus on a close object. It is called accommodation when this happens.

dacryocyst/o is a combining form that refers to "lacrimal sac". A lacrimal sac, also known as a lachrymal sac, is the dilated upper end of the nasolacrimal duct. The lacrimal sac serves as a reservoir for tears overflowing, which are pumped inward and outward by the orbicularis muscle when blinking.

ir/o, irit/o or irid/o is a combining form that refers to "iris". The iris is the pigmented tissue at the eye's outer surface with a pupil in the center that is housed within it. The iris regulates the amount of light entering the eye by controlling the pupil diameter.

labyrinth/o is a combining form that refers to "labyrinth (inner ear)". Located inside the inner ear are organs that provide balance and hearing. The bony labyrinth consists of three specialized structures: the vestibule, the semicircular canal, and the cochlea. Its first function is to convert mechanical signals transmitted by the middle ear into electrical signals, which are then relayed on to the auditory pathway in the brain. A second function is to maintain balance by detecting motion and position.

lacrim/o or dacry/o is a combining form that refers to "tear or tear duct". The tear duct is a narrow tube that drains tears from the eyes. Located beneath the eyelids are glands that make tears. Eyes are kept clean and moisturized by tears. After that, they drain through the tear ducts.