| Question | Answer |
| ___, or taste, is the sensation and perception of chemicals dissolved in saliva. | Gustation |
| ___, or smell, is the sensation and perception of chemicals dissolved in the fluids of the nasal membranes. | Olfaction |
| The five classes of chemoreceptor for gustation are ___, ___, ___, ___, and ___. | salty; sweet; sour; bitter; umami |
| Chemoreceptors in the mouth are located on ___, a specialized structure found on gustatory cells. | gustatory hairs |
| The small visible bumps on the tongue are ___. | mucosal papillae |
| Taste buds are ___ within some types of mucosal papillae, not the mucosal papillae themselves. | microscopic groups of cells |
| Cells which comprise taste buds die after roughly ___, and are replaced by division of ___. | one week; basal cells |
| The nerves which send axons to meet the chemoreceptor cells involved in gustation are cranial nerves #'s ___, ___, or ___. | 7; 9; 10 |
| The ___ is a patch of olfactory epithelium slightly larger than the top surface of the tongue. | olfactory organ |
| The olfactory organ in located in the ___. | roof of the nasal cavity |
| 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) |
| The axons of olfactory cells form the filaments of ___. | cranial nerve 1 (olfactory nerve) |
| 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 |
| Eyelids protect the yee when closed, and also ___ and ___ by blinking. | spread lubricants; remove debris |
| Eyelashes on each lid serve as extremely sensitive ___, triggering reflex eyelid closure when sensation is unexpected. | touch receptors |
| Glands with ducts at the edges of each lid produce ___. | oily secretions that lubricate the lids |
| ___ 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 |
| The lacrimal apparatus includes the ___, which produces tears, and the ducts that drain excess liquid into the ___. | lacrimal gland; nasal passages |
| Tears enter the eye ___ and leave via cuts at the medial corner of the eye (the ___). | superiolaterally; medial canthus |
| Tears contain mucus, ___ and ___, an enzyme, both of which protect the eye from bacteria. | antibodies; lysozyme |
| 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 |
| The eye itself has an outer wall composed of three layers, or "___". | tunics |
| 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 |
| In the back of the eye, the fibrous tunic extends to cover the optic nerve, and is continuous with the ___, | dura mater |
| The ___ (or ___) is the middle layer of the eyeball's wall. | vascular tunic; uvea |
| In the front of the eye, the vascular tunic (or uvea) forms the ___. | iris |
| 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 |
| Posterior to the cillary body is the ___, a dark brown membrane that contains ___. | choroid; the blood vessels that supply the eye tunics |
| The uvea is also known as the ____. | vascular tunic |
| The ___ (or ___) is the innermost layer of the eye. | sensory tunic; retina |
| 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 |
| 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 |
| The inner layer of the retina is a(n) ___ which contains the ___. | transparent neural layer; photoreceptor cells |
| 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 |
| 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 |
| 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 |
| Unlike most proteins, crystallins are never ___. | degraded |
| 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 |
| The anterior cavity of the eye is filled with ___, a clear fluid similar to blood plasma. | aqueous humor |
| The anterior and posterior cavities of the eye are separated by the ___. | lens |
| The anterior and posterior chambers of the anterior cavity of the eye are separated by the ___. | iris |
| 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 |
| The posterior cavity of the eye is filled with ___, a jelly-like substance which is produced ___ and is not ___. | vitreous humor; before birth; replaced |
| Vitreous humor functions to ___ retina and helps to maintain ___ against the pressure of extrinsic muscles. | support; the shape of the eye |
| The axons of the retinal ganglion cells run along the surface of the retina before leaving the eye as the ___. | optic nerve |
| 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 |
| 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 |
| 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 |
| In a relaxed eye, the lens is ___ by the ligaments of the eye. | stretched |
| Contracting the ciliary body of an eye results in ___ tension on the lens, so that it becomes ___. | less; rounder |
| The light sensitive portion of the photoreceptor cells is ___ to maximize surface area, and contains many ___ which absorb light. | wrinkled; photopigment molecules |
| When a photopigment is hit by an appropriate light, it breaks apart into two parts; a vitamin A derivative, ___, and a gylcoprotein, ___. | retinal; opsin |
| 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 |
| Opsin activates a second messenger system which ___ sodium channels in the photoreceptor cells. | closes |
| 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 |
| 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 |
| How many types of retinal exist? How many types of opsin? | one; four |
| There are three sub-types of cones, each of which has its own type of ___ and responds to a different ___. | opsin; color |
| We integrate signals from the three types of cone in order to recognize ___. | many different colors |
| The photopigment in rods is called ___; in bright light, it is present only as ___ and ___. | rhodopsin; retinal; opsin |
| Cones are about ____ sensitive than rods. | 100-fold less |
| The acuity of vision with rods is lower than of vision with cones because ___. | several rods signal each ganglion cell |
| High acuity vision is provided by ___. | cones |
| 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 |
| 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 |
| ___ is a problem is which the cornea is unevenly shaped, so that objects appear wavy. | Astigmatism |
| ___ is nearsightedness; the eye is ___, resulting in a very close field of vision. | Myopia; elongated |
| ___ is farsightedness; the eye is ___, and the lens cannot be ___ enough to focus on near objects. | Hyperopia; shortened; round |
| A cataract refers to ___. | clouding of the lens |
| Two common agents that increase the risk of cataract are ___ and ___. | smoking; UV light |
| 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 |
| Color blindness is due to the genetic absence of one type of ___. | cone |
| Color blindness is due to a defect on the ____ chromosome. | X |
| 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 |
| An immediate adaptation that helps us to see ina dim area is that the ___. | pupil dialates |
| A slow but complete adaptation to a lack of light is made possible by synthesis of ___ in rods. | rhodopsin |
| 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 |
| At the optic chiasma, fibers from the ___ of each retinal field cross over to the opposite side. | medial half |
| The left hemisphere of the brain receives information from the ___. | right half of the visual field |
| Axons from retinal neurons meet to form the ___, and then travel to three areas; the __, __, and __. | optic nerve; thalamus; midbrain; hypothalamus |
| Signals from fibers of the optic nerve which travel to the thalamus ultimately are conveyed to the ___. | optic cerebral cortex |
| Some fibers from the optic nerve travel to the midbrain, which controls ____ and ___. | eye movement; pupil dilation |
| Some fibers from the optic nerve travel to the hypothalamus, which interprets ___ and sets ___. | time of day; circadian rhythm |
| The combination of inhibitory and excitatory processing in the retina in signal processing which emphasizes ___. | edges |
| 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 |
| 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 |
| The outer ear is composed of the visible portion of the ear, as well as the ___ and ___. | external auditory canal; eardrum (OR tympanic membrane) |
| The ___ is the boundary between the outer and middle ear. | tympanic membrane |
| The small, air-filled, mucosa-lined cavity medial to the eardrum is the ___. | middle ear |
| The pharyngotympanic tube connects the ___ to the ____. | middle ear; nasal pharynx |
| Sound is vibration of gas or liquid. Our ability to detect it begins as vibrating air molecules push and pull on the ___. | eardrum |
| The three small bones of the middle ear transmit vibratory motion from the eardrum to the ___. | oval window |
| Excessive motion of the three bones of the middle ear is prevented by the ___ muscle and ___ muscle. | tensor tympani; stapidius |
| The small bones of the middle ear are the ___, ___, and ___. | malleus; incus; stapes |
| The vestibule is a compartment of the inner ear which is the major system involved in ___. | equilibrium |
| The semicircular canals are compartments of the inner ear which sense ___. | rotation of the head |
| The cochlea is a snail shaped organ in the inner ear which is responsible for ___> | hearing |
| The actual organ within the cochlea which is responsible for hearing is the ___. | Organ of Corti |
| As vibrations in the ear cause the eardrum to vibrate, the eardrum pushes against the ___. | ossicles |
