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In the inner ear, stereocilia are the mechanosensing organelles of hair cells, which respond to fluid motion in numerous types of animals for various functions, including hearing and balance. They are about 10–50 micrometers in length and share some similar features of microvilli . [ 1 ]
Alphagan P uses a purite preservative, which is better tolerated by those who have allergic reactions than the older BAK preservative in other eye drops. [13] Furthermore, less selective alpha agonists such as epinephrine may decrease the production of aqueous humor through vasoconstriction of the ciliary body (only for open-angle glaucoma).
The vestibulo-ocular reflex is a reflex eye movement that stabilizes images on the retina during head movement by producing an eye movement in the direction opposite to head movement in response to neural input from the vestibular system of the inner ear, thus maintaining the image in the centre of the visual field. For example, when the head ...
Mammals also have motile cilia or secondary cilia that are usually present on a cell's surface in large numbers (multiciliate), and beat in coordinated metachronal waves. [40] Multiciliated cells are found lining the respiratory tract where they function in mucociliary clearance sweeping mucus containing debris away from the lungs . [ 13 ]
Persons with dry eye conditions can be fitted with punctal plugs that seal the ducts to limit the amount of fluid drainage and retain moisture. During an ear infection, excess mucus may drain through the nasolacrimal duct in the opposite way tears drain. [citation needed] In humans, the tear ducts in males tend to be larger than the ones in ...
The uvea (/ ˈ j uː v i ə /; [1] derived from Latin: uva meaning "grape"), also called the uveal layer, uveal coat, uveal tract, vascular tunic or vascular layer, is the pigmented middle layer of the three concentric layers that make up an eye, precisely between the inner retina and the outer fibrous layer composed of the sclera and cornea.
They are arranged in a circle, and form a sort of frill behind the iris, around the margin of the lens.. They vary from sixty to eighty in number, lie side by side, and may be divided into large and small; the former are about 2.5 mm. in length, and the latter, consisting of about one-third of the entire number, are situated in spaces between them, but without regular arrangement.
It is not always well-defined for nonlinear, nonpassive sensory organs, since they can't function without input energy. For example, a cochlea is not a passive organ, but actively vibrates its own sensory hairs to improve its sensitivity. This manifests as otoacoustic emissions in healthy ears, and tinnitus in pathological ears. [26]