Special Senses

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Question

Answer

___, or taste, is the sensation and perception of chemicals dissolved in saliva.

Gustation

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___, or smell, is the sensation and perception of chemicals dissolved in the fluids of the nasal membranes.

Olfaction

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The five classes of chemoreceptor for gustation are ___, ___, ___, ___, and ___.

salty; sweet; sour; bitter; umami

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Chemoreceptors in the mouth are located on ___, a specialized structure found on gustatory cells.

gustatory hairs

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The small visible bumps on the tongue are ___.

mucosal papillae

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Taste buds are ___ within some types of mucosal papillae, not the mucosal papillae themselves.

microscopic groups of cells

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Cells which comprise taste buds die after roughly ___, and are replaced by division of ___.

one week; basal cells

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The nerves which send axons to meet the chemoreceptor cells involved in gustation are cranial nerves #'s ___, ___, or ___.

7; 9; 10

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The ___ is a patch of olfactory epithelium slightly larger than the top surface of the tongue.

olfactory organ

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The olfactory organ in located in the ___.

roof of the nasal cavity

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As air in inhaled, chemicals carried by it dissolve in the ___ of the olfactory organ, allowing them to bind the chemoreceptors of the olfactory cells found there.

liquid coating the mucosa (or mucus)

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The axons of olfactory cells form the filaments of ___.

cranial nerve 1 (olfactory nerve)

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Eyelids are thick, skin covered folds supported internally by the ___, which also anchor the __ and __, the muscles which control the motion of the eyelids.

tarsal plates; orbicularis oculi; levator palpebrae superioris

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Eyelids protect the yee when closed, and also ___ and ___ by blinking.

spread lubricants; remove debris

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Eyelashes on each lid serve as extremely sensitive ___, triggering reflex eyelid closure when sensation is unexpected.

touch receptors

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Glands with ducts at the edges of each lid produce ___.

oily secretions that lubricate the lids

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___ are transparent mucous membranes that line the eyelids and the anterior surface of the eyeball (except for ___). Their major function is to produce a lubricating mucus that prevents the eye from drying.

Conjunctiva; the cornea

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The lacrimal apparatus includes the ___, which produces tears, and the ducts that drain excess liquid into the ___.

lacrimal gland; nasal passages

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Tears enter the eye ___ and leave via cuts at the medial corner of the eye (the ___).

superiolaterally; medial canthus

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Tears contain mucus, ___ and ___, an enzyme, both of which protect the eye from bacteria.

antibodies; lysozyme

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The extrinsic eye muscles include four ___ which direct the eye's gaze up, down, left, or right. In addition, there are two ___ (superior and inferior) which keep the eye from spinning or twisting.

rectus muscles; oblique muscles

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The eye itself has an outer wall composed of three layers, or "___".

tunics

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The ___ is the outermost layer of the eyeball; in the front it is clear, forming the ___. The surrounding areas are white, and form the ___.

fibrous tunic; cornea; sclera

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In the back of the eye, the fibrous tunic extends to cover the optic nerve, and is continuous with the ___,

dura mater

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The ___ (or ___) is the middle layer of the eyeball's wall.

vascular tunic; uvea

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In the front of the eye, the vascular tunic (or uvea) forms the ___.

iris

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The iris lies between the ___ and the ___ and is continuous with the next region, the cillary body, which is ___.

cornea; lens; smooth muscular tissue that controls the shape of the lens

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Posterior to the cillary body is the ___, a dark brown membrane that contains ___.

choroid; the blood vessels that supply the eye tunics

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The uvea is also known as the ____.

vascular tunic

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The ___ (or ___) is the innermost layer of the eye.

sensory tunic; retina

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The cells of the outer layer of the retina (in relation to the center of the eye) store ___ and act as ___. Both of these functions support the outer layer.

vitamin A; phagocytes

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The retina has two sub-layers; the outer layer of the retina (in relation to the enter of the eye) is pigmented to ___.

prevent light reflection from the back of the eye

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The inner layer of the retina is a(n) ___ which contains the ___.

transparent neural layer; photoreceptor cells

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During youth, the lens is flexible, which allows us to ___. This process is called ___.

alter its shape to focus on nearby or distant objects; accommodation

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Visual acuity is measured by comparison with the average. If one has "20/20" vision, it means that one sees as clearly at 20 feet as ___.

an average person sees at 20 feet

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The lens is made of special proteins called ___. These in turn are made by special cells called ___, which contain no nuclei and few organgelles.

crystallins; lens fibers

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Unlike most proteins, crystallins are never ___.

degraded

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The lens of the eye gets less flexible as we age in part because crystallins are ___ by cells throughout life, and because these proteins are at to become ___ due to poor repair and lack of replacement.

produced; crosslinked

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The anterior cavity of the eye is filled with ___, a clear fluid similar to blood plasma.

aqueous humor

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The anterior and posterior cavities of the eye are separated by the ___.

lens

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The anterior and posterior chambers of the anterior cavity of the eye are separated by the ___.

iris

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The aqueous humor is formed in the ___ of the eye, and is reabsorbed in the ___.

posterior chamber of the anterior cavity; anterior chamber of the anterior cavity

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The posterior cavity of the eye is filled with ___, a jelly-like substance which is produced ___ and is not ___.

vitreous humor; before birth; replaced

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Vitreous humor functions to ___ retina and helps to maintain ___ against the pressure of extrinsic muscles.

support; the shape of the eye

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The axons of the retinal ganglion cells run along the surface of the retina before leaving the eye as the ___.

optic nerve

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The region of the retina where the axons of the retinal ganglion run along the surface of the retina before leaving the eye as the ___.

optic disk; blind spot; photoreceptor cells

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In order to interact with photoreceptors, light must actually pass through the ___; the light-sensitive portion of the photoreceptor cells from the posterior aspect of this layer.

retina

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Most of the light-bending which results in a n image forming on the retina is due to the ___. Many patients benefit from having it reshaped surgically to correct myopia, hyperopia, or astigmatism.

cornea

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In a relaxed eye, the lens is ___ by the ligaments of the eye.

stretched

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Contracting the ciliary body of an eye results in ___ tension on the lens, so that it becomes ___.

less; rounder

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The light sensitive portion of the photoreceptor cells is ___ to maximize surface area, and contains many ___ which absorb light.

wrinkled; photopigment molecules

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When a photopigment is hit by an appropriate light, it breaks apart into two parts; a vitamin A derivative, ___, and a gylcoprotein, ___.

retinal; opsin

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The membrane potential in photoreceptor cells is unusual; ___ is allowed to leak across the membrane. This flow of ions is called the ___.

sodium; dark current

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Opsin activates a second messenger system which ___ sodium channels in the photoreceptor cells.

closes

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When a photoreceptor cell membrane hyperpolarizes, the cell ___. This lets nearby bipolar neurons know that the photoreceptor has been exposed to light.

stops releasing neurotransmitters

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There are two types of photoreceptor cells: ___, which respond to as little as a single photon of light, regardless of color, and ___, which are less sensitive but respond color.

rods; cones

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How many types of retinal exist? How many types of opsin?

one; four

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There are three sub-types of cones, each of which has its own type of ___ and responds to a different ___.

opsin; color

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We integrate signals from the three types of cone in order to recognize ___.

many different colors

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The photopigment in rods is called ___; in bright light, it is present only as ___ and ___.

rhodopsin; retinal; opsin

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Cones are about ____ sensitive than rods.

100-fold less

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The acuity of vision with rods is lower than of vision with cones because ___.

several rods signal each ganglion cell

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High acuity vision is provided by ___.

cones

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The region of the eye which has the most cones (and thus has the highest acuity) ad has no rods at all consists of the ___ and ___.

macula lutea; fovea centralis

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The only region of the eye capable of high-acuity vision (such as that used to read fine print) consists of the ___ and ___.

macula lutea; fovea centralis

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___ is a problem is which the cornea is unevenly shaped, so that objects appear wavy.

Astigmatism

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___ is nearsightedness; the eye is ___, resulting in a very close field of vision.

Myopia; elongated

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___ is farsightedness; the eye is ___, and the lens cannot be ___ enough to focus on near objects.

Hyperopia; shortened; round

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A cataract refers to ___.

clouding of the lens

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Two common agents that increase the risk of cataract are ___ and ___.

smoking; UV light

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If the flow of the aqueous humor out of the eye is partially blocked, the result is ___ called glaucoma, which will eventually damage the retina and cause blindness.

an increase int he internal pressure of the eye; blindness

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Color blindness is due to the genetic absence of one type of ___.

cone

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Color blindness is due to a defect on the ____ chromosome.

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When we first enter a dim area, we are unable to see because ___ and ___.

all rhodopsin in rods is photobleached; the cones are not sensitive enough to detect dim light

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An immediate adaptation that helps us to see ina dim area is that the ___.

pupil dialates

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A slow but complete adaptation to a lack of light is made possible by synthesis of ___ in rods.

rhodopsin

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Since retinal is made from ___, dark adaptation due to rhodopsin synthesis from retinal and opsin is sensitive to a dietary deficiency in this substance.

vitamin A

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At the optic chiasma, fibers from the ___ of each retinal field cross over to the opposite side.

medial half

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The left hemisphere of the brain receives information from the ___.

right half of the visual field

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Axons from retinal neurons meet to form the ___, and then travel to three areas; the __, __, and __.

optic nerve; thalamus; midbrain; hypothalamus

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Signals from fibers of the optic nerve which travel to the thalamus ultimately are conveyed to the ___.

optic cerebral cortex

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Some fibers from the optic nerve travel to the midbrain, which controls ____ and ___.

eye movement; pupil dilation

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Some fibers from the optic nerve travel to the hypothalamus, which interprets ___ and sets ___.

time of day; circadian rhythm

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The combination of inhibitory and excitatory processing in the retina in signal processing which emphasizes ___.

edges

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Depth perception is made possible by processing in the ___, which separates signals form the two eyes before forwarding the signals to the visual cortex.

thalamus

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The ___ contains an exact map of the retina, so that a ganglion cell's action potential in the retina is matched by the excitation of a single neuron in this region.

visual cortex

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The outer ear is composed of the visible portion of the ear, as well as the ___ and ___.

external auditory canal; eardrum (OR tympanic membrane)

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The ___ is the boundary between the outer and middle ear.

tympanic membrane

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The small, air-filled, mucosa-lined cavity medial to the eardrum is the ___.

middle ear

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The pharyngotympanic tube connects the ___ to the ____.

middle ear; nasal pharynx

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Sound is vibration of gas or liquid. Our ability to detect it begins as vibrating air molecules push and pull on the ___.

eardrum

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The three small bones of the middle ear transmit vibratory motion from the eardrum to the ___.

oval window

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Excessive motion of the three bones of the middle ear is prevented by the ___ muscle and ___ muscle.

tensor tympani; stapidius

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The small bones of the middle ear are the ___, ___, and ___.

malleus; incus; stapes

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The vestibule is a compartment of the inner ear which is the major system involved in ___.

equilibrium

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The semicircular canals are compartments of the inner ear which sense ___.

rotation of the head

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The cochlea is a snail shaped organ in the inner ear which is responsible for ___>

hearing

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The actual organ within the cochlea which is responsible for hearing is the ___.

Organ of Corti

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As vibrations in the ear cause the eardrum to vibrate, the eardrum pushes against the ___.

ossicles

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Created by: stinsemi0043