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
Nystagmus is __________.
involuntary trailing of eyes in one direction, then rapid movement in the other
What type of fluid fills the membranous labyrinth?
endolymph
Sound waves pass through this canal on their way toward the eardrum.
external acoustic meatu
The bony labyrinth is part of the ________.
internal ear
The cochlear duct (scala media) contains ______
endolymph
The hair cells that detect sound vibrations lie on the ________ membrane.
basilar
Sound localization can be tested by ________.
listening for the tick of a watch as the watch is held in various locations around the head
Within the inner ear, this structure is involved in dynamic equilibrium.
the semicircular canals
Hair cells in the crista ampullaris are ________.
embedded in a gelatinous cap
The pharyngotympanic (auditory) tube connects the ________ to the nasopharynx.
middle ear
Which of the following might cause sensorineural deafness?
listening to very loud music on a daily basis
The auditory ossicles transmit and amplify sound waves in the middle ear. In sequence, sound waves pass from: ________.
malleus—incus—stapes.
Why is it difficult for “weightless” astronauts in space to know whether they are right side up or upside down?
Maculae that report head position depend upon the gravitational pull on the otoliths.
Which of the following structures in the inner ear is involved in dynamic equilibrium?
semicircular canals
Receptors for olfaction and taste are classified as chemoreceptors because they respond to dissolved chemicals.
True
Olfactory receptors are __________ sensory neurons whose olfactory cilia extend outward from the epithelium.
bipolar
Vallate papillae are arranged in a V formation on the __________ surface of the tongue.
posterior
Taste buds typically respond optimally to one of the five basic taste sensations.
True
You will use absorbent cotton and oil of wintergreen, peppermint, or cloves to test for olfactory _________
adaptation
Name the types of papillae that contain taste buds.
fungiform, foliate, and vallate
Olfactory receptor cells differ from all other receptors for special senses in that they ________.
are neurons
Nerve fibers from the olfactory bulb project directly to ________.
the olfactory cortex (uncus)
Taste receptor cells are found in structures called ________.
taste buds
Which structures form a V-shape on the posterior portion of the tongue?
vallate papillae
Acids primarily activate receptors that respond to ________ tastes.
sour
Salty taste seems to be due to ________.
Na+ ions
The axons of olfactory receptor cells constitute _______
CN I
Tastes associated with caffeine, quinine, or aspirin are detected primarily by ________ taste receptors.
bitter
Adaptation of the olfactory epithelium ________.
occurs readily in the presence of odorants
________ are precursor cells that give rise to new gustatory epithelial cells.
Basal epithelial cells
Taste buds on the tongue are often associated with epithelial projections called
lingual papillae
Pupillary muscle groups are controlled by the ANS. Parasympathetic activation causes pupillary ________, and sympathetic activation causes ________.
constriction; dilation
A type of farsightedness that results from a loss of lens elasticity with age is
presbyopia.
Visual pigments are derivatives of the compound
rhodopsin
An abnormal blind spot appearing in vision is called a(n)
scotoma
The gelatinous material that gives the eyeball its basic shape is the
vitreous humor.
A structure that is located at the medial angle and contains glands that contribute to a gritty deposit is the
lacrimal caruncle.
The hair cells of the utricle and saccule are clustered in
maculae
The abnormality that develops when a lens loses its transparency is known as
a cataract.
The primary cause of blindness in the United States is
diabetic retinopathy.
Between the bony and membranous labyrinth flows ________, while the membranous labyrinth contains ________.
perilymph; endolymph
Which of the following types of sensory information reaches the cerebral cortex directly?
olfactory
The ________ is a region of dense bone that surrounds and protects the membranous labyrinth.
bony labyrinth
The part of the eye that determines eye color is the
iris.
Olfactory glands
coat the olfactory epithelium with a pigmented mucus.
Jonathan received a strong blow to the eye. The eyeball remained intact but he suddenly could not see. This has likely caused
a detached retina.
Stimulation of receptors within the trigeminal nerve might produce a perception of
peppery hot.
A sound with a frequency of 12,000 hertz would
be high-pitched.
Each gustatory cell extends ________ (called taste hairs) into the surrounding fluids through a narrow taste pore.
microvilli
The sensory receptors of the semicircular canals are located in the
ampullary crest.