The Eye and Vision: Anatomy 1. Several accessory eye structures contribute to the formation of tears and/or help lubricate the eyeball. Match the described accessory structures with their secretion by choosing answers from the key. Key: conjunctivae CONJUNCTIVAE TARSAL GLANDS LACRIMAL GLANDS 2. lacrimal glands tarsal glands 1. mucus 2. oil 3. lysozyme The eyeball is wrapped in adipose tissue within the orbit. What is the function of the adipose tissue? Cushioning and protection. It acts like a shock absorber, cushioning the eyeball from impact and injury. It provides a source of energy for the muscles that control eye movement. 3. Why may it be necessary to blow your nose after having a good cry? There are two main reasons why your nose might run after a good cry, and blowing your nose can help clear things up: a. Tears drain through your nose your eyes don't just overflow they have a drainage system! Tears travel through tiny tubes called tear ducts that empty into your nose. When you cry a lot, this system can get overwhelmed, and tears mix with mucus in your nasal cavity, leading to a runny nose. Blowing your nose helps expel this excess fluid. b. Crying can irritate your nose the emotional response that leads to crying can also trigger a general increase in mucus production in your nose. This can be your body's way of trying to flush out any irritants or allergens that might have contributed to the emotional response. Blowing your nose helps remove this extra mucus. 4. What is a sty? A sty is a small, painful bump that forms on the edge of your eyelid. It often looks similar to a pimple and is caused by a bacterial infection in one of the tiny oil glands near your eyelashes. . A sty usually goes away on its own after a few days, but you can help it heal faster by applying warm compresses to your eye several times a day. Conjunctivitis? Conjunctivitis, also known as pink eye, is an inflammation of the conjunctiva – the thin layer that covers the white part of your eye and lines your eyelids. It can be caused by bacteria, viruses, allergies or irritants like dust or smoke. Symptoms include redness, itching, swelling and discharge from one or both eyes. Conjunctivitis usually clears up within a week or two without treatment, but in some cases, antibiotics may be needed to treat bacterial infections. 5. What seven bones form the bony orbit? (Think! If you can’t remember, check a skull or your textbook.) 1. 2. MAXILLA ZYGOMATIC BONE 3. 4. 5. LACRIMAL BONE PALATINE BONE FRONTAL BONE 6. 7. ETHMOID BONE SPHENOID BONE 6. M O S I E F D Identify the lettered structures on the diagram by matching each letter with one of the terms to the right. anterior chamber anterior segment bipolar cells Choroid ciliary muscle ciliary process ciliary zonule A K Q T C B R Cornea dura mater fovea centralis ganglion cells Iris Lens optic disc L U P J H D G Optic nerve photoreceptors posterior chamber retina sclera sclera venous sinus vitreous body in posterior segment Notice the arrows drawn close to the left side of the iris in the diagram above. What do they indicate? Production and drainage of the aqueous humor into the canal of Schlemm. 7. Match the key responses with the descriptive statements that follow. Key: aqueous humor choroid ciliary zonule CILIARY ZONULE AQUEAOUS HUMOR OPTIC DISC cornea fovea centralis iris lens optic disc retina 1. attaches the lens to the ciliary body 2. fluid filling the anterior segment of the eye 3. the blind spot sclera scleral venous sinus vitreous humor IRIS SCLERA VENUS SINUS RETINA VITREOUS HUMOR CHOROID FOVEA CENTRALIS LENS CORNEA SCLERA 8. 4. contains muscle that controls the size of the pupil 5. drains the aqueous humor from the eye 6. layer containing the rods and cones 7. substance occupying the posterior segment of the eyeball 8. forms most of the pigmented vascular tunic 9. tiny pit in the macula lutea; contains only cones 10. important light-bending structure of the eye; shape can be modified 11. anterior transparent part of the fibrous tunic 12. composed of tough, white, opaque, fibrous connective tissue The intrinsic eye muscles are under the control of which of the following? (Circle the correct response.) autonomic nervous system somatic nervous system Dissection of the Cow (Sheep) Eye 9. What modification of the choroid that is not present in humans is found in the cow eye? TAPETUM LUCIDUM What is its function? Provide the light-sensitive retinal cells with a second opportunity for photo-photoreceptor stimulation, thereby enhancing visual sensitivity at low light levels. 10. Describe the appearance of the retina (Cow). • Located at the back of the eye at a specific spot called the blind spot. • Responsible for detecting and converting light into electrical signals that the brain interprets. • Have tapetum lucidum behind it. A blue reflective layer responsible for enhancing night vision by reflecting light back through the retina, increasing the chances of capturing available light. 11. Use terms from the key to complete the statements concerning near and distance vision. (Some terms may be used more than once.) Key: contracted decreased increased loose relaxed taut During distance vision: The ciliary muscle is RELAXED, ciliary zonule is TAUT, convexity of the lens is DECREASED, and light refraction is DECREASED. During close vision: The ciliary muscle is CONTRACTED, the ciliary zonule is RELAXED, lens convexity is INCREASED, and light refraction is INCREASED. 12. Explain why the part of the image hitting the blind spot is not seen. There are no light-sensitive cells present in that specific area of the retina. Photoreceptors, namely rods and cones, are responsible for detecting light and transmitting visual signals to the brain. The lack of photoreceptors in the blind spot causes any image that falls on that area of the retina cannot be detected or seen. 13. Match the terms in column B with the descriptions in column A: Column A REFRACTION ACCOMODATION EMMTROPIA HPEROPIA 1. 2. 3. 4. light bending ability to focus for close (under 20 ft) vision normal vision inability to focus well on close objects (farsightedness) MYOPIA 5. nearsightedness Column B accommodation astigmatism convergence emmetropia hyperopia ASTIGMATISM 6. CONVERGENCE 7. blurred vision due to unequal curvatures of the lens or cornea medial movement of the eyes during focusing on close objects 14. Record your Snellen eye test results below: (SKIP) Left eye (without glasses) myopia refraction (with glasses) Right eye (without glasses) (with glasses) Is your visual acuity normal, less than normal, or better than normal? Explain. Explain why the examiner tests each eye separately when using the Snellen eye chart. The given text is about eye tests and vision. It asks the reader to record their results from a Snellen eye test, which measures visual acuity (how well someone can see). The reader must record their results for each eye with and without glasses, and then determine if their visual acuity Is normal, less than normal, or better than normal. The examiner tests each eye separately when using the Snellen eye chart because it allows them to identify any differences in vision between the two eyes. This helps diagnose conditions such as amblyopia (lazy eye) or strabismus (crossed eyes). Explain 20/40 vision. 20/40 vision means that someone can see at 20 feet what a person with normal vision can see at 40 feet. This indicates that their visual acuity is less than normal. Explain 20/10 vision. 20/10 vision means that someone can see at 20 feet what a person with normal vision can only see at 10 feet. This indicates that their visual acuity is better than normal. 15. Define astigmatism: Astigmatism is an imperfection in the curvature of the cornea or lens of the eye, causing blurred or distorted vision at any distance. It is a common vision problem that occurs when the front surface of the eye (cornea) or the lens inside the eye has irregular curves, resulting in a refractive error. The irregular shape of the cornea or lens prevents light rays from focusing properly on the retina, leading to blurry vision. 16. Record the distance of your near point of accommodation as tested in the laboratory: (SKIP) 17. How can you explain the fact that we see a great range of colors even though only three cone types exist? The trichromatic theory of color vision explains this phenomenon. According to this theory, our three types of cone cells are sensitive to different wavelengths of light - short (blue), medium (green), and long (red) wavelengths. These three cone types provide the basic building blocks for color vision. Even though we only have three cone types, the brain can combine the signals from these cones in different ratios to perceive a vast array of colors. The relative activation of the three cone types determines the specific color we perceive. 18. In the experiment on the convergence reflex, what happened to the position of the eyeballs as the object was moved closer to the subject’s eyes? According to the information gathered from the search results, in the experiment on the convergence reflex, the position of the eyeballs moved medially (inward) as the object was moved closer to the subject's eyes. Which extrinsic eye muscles control the movement of the eyes during this reflex? MEDIAL RECTI MUSCLES What is the value of this reflex? It allows the eyes to focus on nearby objects by coordinating the movement of the eyes, the accommodation of the lens, and the constriction of the pupils. This reflex is part of the accommodationconvergence reflex, which is essential for binocular vision and depth perception. If these muscles were unable to function, what would be the visual result? If the medial recti muscles were unable to function, the visual result would be an inability to converge the eyes on nearby objects. This would lead to difficulties with binocular vision, depth perception, and focusing on close-up tasks. 19. Many college students struggling through mountainous reading assignments are told that they need glasses for “eyestrain.” Why is looking at close objects more of a strain on the extrinsic and intrinsic eye muscles than looking at far objects? When focusing on a close object, the ciliary muscle (intrinsic eye muscle) contracts, causing the lens to become more curved and increase its refractive power. This allows the eye to focus the light from the close object onto the retina. Maintaining this lens curvature for an extended period can lead to fatigue and strain in the ciliary muscle. Also, the medial rectus muscles (extrinsic eye muscles) contract, causing the eyes to turn inward and converge on the close object. Maintaining this convergence for a long time can lead to strain in the extrinsic eye muscles. In contrast, when looking at distant objects, the eye muscles are more relaxed, as the lens is flatter and the eyes are parallel, requiring less active accommodation and convergence. The Ear and Hearing and Balance: Anatomy 20. Select the terms from column B that apply to the column A descriptions. (Some terms are not used, and others are used more than once.) Column A Column B MALLEUS, INCUS, STAPES 1. collectively called the auditory ossicles auricle cochlea SEMICIRCULAR CANALS, 2. ear structures involved with balance endolymph VESTIBULE external acoustic TYMPANIC MEMBRANE 3. transmits sound vibrations to the auditory meatus ossicles incus SEMICIRCULAR CANALS 4. three circular passages, each in a different malleus plane of space oval window OVAL WINDOW 5. transmits the vibratory motion of the stapes to perilymph the fluid in the ear pharyngotympanic PHARYNGOTYMPANIC 6. passage between the throat and the tympanic (auditory) tube (AUDITORY) TUBE cavity round window ENDOLYMPH 7. fluid contained within the membranous semicircular canals labyrinth stapes tympanic membrane vestibule 21. Identify all indicated structures and ear regions that are provided with leader lines or brackets in the following diagram. PINNA INTERNAL EAR MIDDLE EAR TYMPANIC MEMBRANE SEMICIRCULAR CANAL VESTIBULE VESTIBULOCOCHLEAR NERVE OVAL WINDOW COCHLEA ROUND WINDOW STAPES LOBULE EXTERNAL AUDITORY CANAL INCUS MALLEUS EXTERNAL EAR PHARYNGOTYMPANIC (AUDITORY) TUBE AUDITORY OSSICLES 22. Match the membranous labyrinth structures listed in column B with the descriptive statements in column A. (Some terms are used more than once.) Column A Column B COCHLEAR DUCT 1. contains the spiral organ Ampulla ampullary cupula UTRICLE AND SACCULE 2. sites of the maculae BASILAR MEMBRANE 3. hair cells of the spiral organ rest on this basilar membrane cochlear duct membrane TECTORIAL MEMBRANE 4. gel-like membrane overlying the hair cells of cochlear nerve otoliths the spiral organ saccule AMPULLA 5. contains the cristae ampullaris semicircular ducts VESTIBULAR NERVE 6. carries equilibrium information to the brain tectorial membrane SEMICIRCULAR DUCTS 7. three internal ear structures oriented in the utricle three planes of space vestibular nerve COCHLEAR NERVE 8. carries auditory information to the brain AMPULLARY CUPULA 9. gelatinous cap overlying hair cells of the crista vestibular sacs OTOLITHS ampullaris 10. grains of calcium carbonate in the maculae 23. Describe how sounds of different frequency (pitch) are differentiated in the cochlea. The frequency is differentiated by the length of the basilar membrane fibers. High pitch sounds make it close to oval window, low pitch is further up basilar membrane near apex of cochlea. It depends a lot on the strength of the vibration of the fluid stimulating the hair cells. 24. Explain the role of the endolymph of the semicircular canals in activating the receptors during angular motion. The endolymph pushes scapula in direction opposite to that of angular motion. This movement depolarizes hair cells, resulting in impulse transmission up vestibular division of the cranial nerve VIII to the brain. 25. Explain the role of the otoliths in perception of static equilibrium (head position). When the head moves, otoliths move in response to variation in gravitational pull as they deflect different hair cells, they hyperpolarize or depolarize the hair cells and modify the rate of impulse transmission along vestibular nerve. Hearing and Balance Tests NOTE: (26 – 28, NO EXPERIMENT WAS CONDUCTED. AN ALTERNATIVE RESEARCH WAS MADE.) 26. Was the hearing acuity measurement made during the experiment (page 205) the same or different for both ears? REPHRASED TO: What is the usual result of hearing acuity measurement on both ears? Are they the same or different? What factors might account for a difference in the acuity of the two ears? Based on the collective research that we have gathered; the results of hearing acuity measurement can vary. The audiogram is commonly used to graphically represent the results of a hearing test. It displays a person’s hearing sensitivity across different sound intensities (loudness) and frequencies (pitches) for both ears. Results may fall into different categories based on the degree of hearing loss: 1. Normal hearing: audiogram will show that they can hear sounds within the typical range of intensities and frequency on both ears. 2. Mild, moderate, severe, or profound hearing loss: if there’s a hearing loss present, the degree of hearing loss can be categorized based on the thresholds measured on the audiogram. The thresholds indicate the softest sounds a person can hear at different frequencies. Severity of hearing loss can vary between the ears. Note that specific results can vary based on the individual, the testing method used, and the interpretation guidelines. According to the available research and literature that was collectively gathered, there are several factors that can account for a difference in hearing acuity between the two ears. These factors can be broadly categorized into the following: Conductive Hearing Loss One of the primary factors that can lead to a difference in hearing acuity between the two ears is conductive hearing loss. Conductive hearing loss occurs when there is an issue with the outer or middle ear, such as a blockage, infection, or damage to the eardrum or middle ear bones. Conditions like ear wax buildup, fluid in the middle ear, or perforations in the eardrum can affect the transmission of sound waves, resulting in a discrepancy in hearing abilities between the two ears (Healthline, 2021). Sensorineural Hearing Loss Another significant factor is sensorineural hearing loss, which is caused by damage to the inner ear or the auditory nerve. According to the Cleveland Clinic (2023), this type of hearing loss can be attributed to various factors, including aging, exposure to loud noises, genetic predisposition, or certain medical conditions. Sensorineural hearing loss can affect both ears, but the severity and configuration of the loss may differ between them, leading to a difference in acuity. Ear Infections Ear infections, particularly chronic or recurrent ones, can also contribute to differences in hearing acuity. When the middle ear is affected by inflammation or the presence of fluid, it can impede the transmission of sound, leading to a disparity in hearing abilities between the two ears (Audiologists.org, 2023). Anatomical Variations Anatomical variations in the structure of the outer or middle ear can also play a role in the differences in hearing acuity. As mentioned in the Healthline article (2021), factors such as the size, shape, or positioning of the ear canal, eardrum, or middle ear bones can affect the way sound waves are conducted, resulting in unequal hearing abilities. Noise Exposure Exposure to loud noises, whether in the workplace or through recreational activities, can also contribute to differences in hearing acuity between the ears. If one ear is subjected to more intense or prolonged noise exposure, it may experience greater damage to the inner ear's hair cells, leading to a more pronounced hearing loss in that ear (Verywell Health, 2022). Medical Conditions and Medications Lastly, certain medical conditions or the use of ototoxic medications can impact hearing acuity and may affect one ear more than the other. As mentioned in the NCBI article (2018), conditions like Ménière's disease, autoimmune disorders, or the use of certain medications that can damage the inner ear can result in differences in hearing acuity between the two ears. In conclusion, the factors that can account for a difference in hearing acuity between the two ears include conductive hearing loss, sensorineural hearing loss, ear infections, anatomical variations, noise exposure, and medical conditions or medications. Understanding these factors is crucial in identifying the underlying causes and providing appropriate interventions to address the disparity in hearing abilities. 27. During the sound localization experiment (page 205), in which position(s) was the sound least easily located? How can you explain this observation? REPHRASED TO: During a sound localization experiment, in which usual position(s) was the sound least easily located? How do experts explain this observation? According to the gathered research literature, during sound localization experiments, the positions where sounds are typically the least easily located are in the front and rear of the listener. In a study published in the Proceedings of the National Academy of Sciences, researchers found that "sound localization is most accurate in the lateral (left/right) dimension and least accurate in the front-back dimension" (Middlebrooks & Green, 1991). The experts explain this observation as follows: 1. Front-back confusion: According to the article "Sound Localization of Listeners With Normal Hearing, Impaired Hearing" published in the American Journal of Audiology, "the auditory system relies on subtle differences in the timing and intensity of sounds reaching the two ears to determine the lateral position of a sound source. However, these binaural cues are less reliable for determining the front-back position of a sound source" (Cameron et al., 2022). This front-back confusion is a well-documented phenomenon in sound localization. 2. Lack of spectral cues: The Healthline article "How to Read an Audiogram: Graph, Symbols, and Results Explained" explains that "the shape of the outer ear, or pinna, provides important spectral cues that help the brain determine the elevation and front-back position of a sound source. When a sound comes from the front or rear, these spectral cues are less distinct, making it harder to localize the sound" (Healthline, 2021). 3. Ambiguous binaural cues: The NCBI resource "Sound Localization in Noise by Normal-Hearing Listeners and Cochlear Implant Users" states that "when a sound source is located directly in front of or behind the listener, the binaural cues (interaural time and level differences) that the auditory system uses to localize sounds become ambiguous, leading to front-back confusions" (Goupell et al., 2013). In summary, the positions where sounds are the least easily located during sound localization experiments are typically in the front and rear of the listener. Experts explain this observation as a result of front-back confusion, lack of distinct spectral cues, and ambiguous binaural cues, which make it more challenging for the auditory system to accurately determine the location of the sound source in these directions. 28. When the tuning fork handle was pressed to your forehead during the Weber test, where did the sound seem to originate? Where did it seem to originate when one ear was plugged with cotton? How do sound waves reach the cochlea when conduction deafness is present? REPHRASED TO: When the tuning fork handle was pressed to the subject’s forehead during the Weber test, where did the sound seem to originate? Where did it seem to originate when one ear was plugged with cotton? How do sound waves reach the cochlea when conduction deafness is present? According to multiple research sources gathered, the results of the Weber test can provide insights into the type and location of hearing loss. When the tuning fork handle is pressed to the subject's forehead during the Weber test, the sound should be perceived as originating in the center of the head or be equally loud in both ears if the hearing is normal. As explained in the StatPearls article, "The Weber test is a useful, quick, and simple screening test for evaluating hearing loss. The test can detect unilateral conductive and sensorineural hearing loss" (StatPearls, 2023). However, when one ear is plugged with cotton during the Weber test, the sound will typically seem to originate in the plugged ear. According to the research paper "Comparing the diagnostic accuracy of audiometric Weber test and tuning fork Weber test in patients with conductive hearing loss," this is because "in conductive hearing loss, the vibrations from the tuning fork are more easily conducted through the bones of the skull to the cochlea of the plugged ear, making the sound appear to come from that side" (Agarwal et al., 2022). When conduction deafness is present, the sound waves reach the cochlea through an alternative pathway, known as bone conduction. As described in the StatPearls article, "In normal hearing, sound waves travel through the external auditory canal, causing the eardrum to vibrate, which then transmits the vibrations through the middle ear bones (ossicles) to the oval window of the cochlea. However, in conduction deafness, this normal sound transmission pathway is disrupted, and the sound waves must reach the cochlea through bone conduction" (StatPearls, 2023). Bone conduction refers to the transmission of sound waves through the bones of the skull, bypassing the outer and middle ear. This allows the vibrations to directly stimulate the inner ear and reach the cochlea, enabling the person to perceive the sound, albeit with reduced volume and clarity compared to normal hearing (StatPearls, 2023). In summary, according to multiple research sources, during the Weber test, the sound should seem to originate in the center of the head in normal hearing, but when one ear is plugged, the sound will appear to come from the plugged ear. In conduction deafness, sound waves reach the cochlea through bone conduction, bypassing the impaired outer or middle ear structures. 29. The Rinne test evaluates an individual’s ability to hear sounds conducted by air or bone. Which is typical of normal hearing? In normal hearing, people should be able to hear sounds better when they’re conducted by air than by bone. During Rinne test, if someone can hear sounds better in their ear with an air-conducted sound than in their ear with bone-conducted sound, then that means they have typical or normal hearing. 30. Define nystagmus: Nystagmus is a condition characterized by rapid, repetitive, and involuntary movements of the eyes. These eye movements can occur in different directions, including side to side (horizontal nystagmus), up and down (vertical nystagmus), or in a circular motion (rotary or torsional nystagmus). 31. What is the usual reason for conducting the Romberg test? (Use your textbook if necessary.) Was the degree of sway greater with the eyes open or closed? Why? Romberg test is conducted to assess an individual's ability to maintain balance. It is often performed when a person experiences dizziness or has a history of falling. The test involves standing with the feet close together and arms at the sides, first with the eyes open and then with the eyes closed. The healthcare provider observes any swaying or loss of balance during the test. The degree of sway is usually greater when the eyes are closed during the Romberg test. This is because visual input plays a significant role in maintaining balance. When the eyes are closed, the reliance on visual cues is reduced, and the body must rely more on proprioception (sensory information from muscles and joints) and the vestibular system (inner ear balance organs) to maintain balance. 32. Normal balance, or equilibrium, depends on input from a number of sensory receptors. Name them. • Visual system (eyes) • Proprioceptive system (muscle and joints) • Vestibular system (inner ear) • Somatosensory system (skin, muscles, tendons) All of these systems work together to provide us with information about our position and movement in space so we can maintain our balance while standing or walking. Chemical Senses: Localization and Anatomy of Olfactory and Taste Receptors 33. Describe the cellular makeup and the location of the olfactory epithelium. The olfactory epithelium is a thin, cellular tissue that is located in the nasal cavity (at the upper part of the nasal cavity, above the cribriform plate of the ethmoid bone, which separates the nasal cavity from the brain). It includes several types of cells, namely the olfactory receptor sensory neuron, supporting cells, and basal cells. The olfactory sensory neuron are the ones responsible for converting the chemical stimuli from the environment into electrical signals that can be interpreted by the brain. The supporting cells provide physical and metabolic support to the sensory neurons. The basal cells are stem cells capable of dividing and differentiating into new olfactory sensory neurons. 34. Name five sites where receptors for taste are found, and circle the predominant site: TONGUE EPIGLOTTIS CHEEK SOFT PALATE PHARYNX 35. Describe the cellular makeup and arrangement of a taste bud. (Use a diagram, if helpful.) Taste bud is composed of taste receptor cells, supporting cells, and basal cells. The receptor cells are responsible for detecting tastes and sending signals to the brain. The supporting cells provide structural support and nourishment to the taste receptor cells. The basal cells are stem cells that can divide and differentiate into taste receptor cells. 36. Taste and smell receptors are both classified as CHEMORECEPTORS because they both respond to CHEMICAL STIMULI. 37. Why is it impossible to taste substances if your tongue is dry? The presence of saliva helps dissolve chemicals in the food that stimulate taste receptors. Without enough saliva, the substances cannot reach your taste buds properly and therefore cannot be tasted accurately or at all. This is why it’s important to keep hydrated and maintain a healthy amount of saliva in your mouth if you want to fully experience different tastes. 38. Explain why a cold, greasy hamburger is unappetizing to most people. 1. Taste – the basic sensation we perceive on our taste buds. E.g., The BSED Science 2B students were given different samples of fruit juices with varying levels of sweetness as an experiment. The juice with the balanced level of sweetness is likely to be more appreciated than those that have overly or lacking sweetness. 2. Texture – the physical characteristics of the food, such as crunchiness, smoothness, or chewiness. E.g., The BSED Science 2B students was given samples of chocolate with varying textures, such as creamy, crunchy, or grainy. The chocolate with the smooth texture is likely to be more appreciated. 3. Aroma - closely linked to our sense of smell and greatly influences our overall flavor experience. E.g., The BSED Science 2B students were presented samples of coffee, each having a distinct aroma profile. The coffee with a rich, aromatic profile is likely to be more appreciated. With the information presented above about taste, texture, and aroma. Let us now explain why a cold, greasy hamburger is unappetizing to most people. 1. 2. 3. Taste – when the hamburger is cold, the taste sensations may be muted or the chemicals that stimulate the taste receptors cannot be dissolved easily. Texture – when the hamburger is cold, its texture becomes greasy. The fat in the hamburger solidifies which create the greasy and heavy texture. Aroma – when the hamburger is cold, its aroma diminishes because the molecules responsible for its aroma is less energized (not enough heat to get energy from). 39. How palatable is food when you have a cold? Explain. Less palatable. When we have a cold, our senses become less active, particularly our sense of smell and taste for these two are linked with each other. A decrease in the sense of smell alters our perception of taste because the brain is being deprived of the necessary compounds that the olfactory receptor detects which in turn releases signals that the brain interprets. These interpreted signals are combined with the signals that the taste buds acquire. With our power to perceive smell and taste being weakened, we can only perceive basic tastes of sweet, sour, salty, bitter, and umami (or the perception of meaty flavors). The complex and subtle flavors cannot be applied.
