Ch 17 The special senses Flashcards
Identify the fluid filled space between the cornea and iris.
Anterior chamber
Identify the structure that regulates the amount of light entering the posterior segment of the eye.
Iris
The iris is a muscular structure composed of both circular and radially arranged smooth muscle cells. It is capable of changing the shape of the pupil, thereby adjusting the amount of light passing through the lens.
Identify the areas that are filled with aqueous humor.
The anterior and posterior chambers
The iris divides the eye into the anterior and posterior segment
False
The lens divides the eye into the anterior segment, located in front of the lens, and the posterior segment, located behind the lens.
The pupil can adjust its size independent of the iris.
false
The iris changes the diameter of the opening at its center, which is known as the pupil.
The wall of the eye has three layers. The outermost fibrous layer is made up of the opaque white sclera and the transparent __________.
cornea
At the optic chiasma, the fibers from the medial side of each eye cross over to the opposite side.
True
Identify the type of neuronal cell that detects bright light and provides high-resolution color vision.
The cone cells are photoreceptor cells that require brighter light, By differentiating input from three different types of cones, the brain can differentiate color and high resolution.
The ________ carry tears into the nasal cavity
nasolacrimal ducts
Of the glands listed here, which one produces the oily substance that covers the conjunctiva?
tarsal glands
The photoreceptors in the retina that detect light are _____
rods and cones
The visual pathway terminates in this cortical area.
visual cortex
This extrinsic eye muscle elevates the eye and turns it medially.
superior rectus
The ________ is a blind spot on the retina, while the ________ contains only cones and is the retinal area of greatest visual acuity.
optic disc, fovea centralis
The anterior segment of the eye contains a fluid called ________
aqueous humor
The retinal cells that are closest to the vascular layer are the ________.
rods and cones
Axons of ganglion cells form the optic tract. These fibers synapse with neurons in the ________
thalamus
Contraction of muscles within this structure leads to alteration in the shape of the lens.
ciliary body
Photoreceptors are distributed over the entire neural retina, except where the optic nerve leaves the eyeball. This site is called the _________
optic disc
People with difficulty seeing objects at a distance are said to have myopia.
True
__________ eye muscles are controlled by the autonomic nervous system.
Intrinsic
What term refers to the eye’s moving medially to track items close at hand?
convergence
Convergence is the medial rotation of the eyeballs by the medial rectus muscles so that we can fixate on a close object.
The image formed on the retina as light passes through the eye is reversed left to right, inverted, and smaller than the object. It is called a ________ image.
real
The normal, or ________, eye accommodates properly.
emmetropic
Astigmatism ________.
results from irregular curvatures of the lens or cornea
The results of a test of visual acuity are 20/15. This individual ________.
has better than normal vision
Binocular vision ________.
provides depth perception (three-dimensional vision)
This type of examination allows one to study the interior of the eyeball.
an ophthalmoscopic examination
The ear is divided into __________ major areas.
3
Sound waves that enter the external acoustic meatus eventually encounter the __________, which then vibrates at the same frequency as the sound waves hitting it.
tympanic membrane
The snail-like __________, found in the internal ear, contains sensory receptors for hearing.
cochlea
The equilibrium apparatus of the ear, the vestibular apparatus, is found in the __________.
internal ear