NROS 418 EXAM 3 ACTUAL QUESTIONS WITH

NROS 418 EXAM 3 (ACTUAL / ) QUESTIONS WITH

VERIFIED CORRECT ANSWERS

Describe the anatomy of a taste bud and its relationship to papillae on the tongue. Include the taste cell/gustatory receptor plan for a taste bud. Taste cells are not neurons, but they synapse onto what neurons and project to where? - --- Answes-----Taste receptors are clustered in taste buds, multiple taste buds on one papillae. Taste bud has a small opening, taste pore, at the epithelial surface. Each taste bud has ~100 taste receptor cells. Each taste cell extends microvilli into taste pore which is where it receives tastants. Taste cells contacts afferent fibers of gustatory sensory neurons and project to sensory ganglion which relay information through the brain stem and thalamus to the gustatory cortex

Bitter taste is encoded by a 30-or-so-member family of gustatory receptors (T2R family). They have high affinity for bitter tastants and a single taste cell can express more than one T2R family member, which makes it hard to discriminate among bitter tastants. Why is this not considered a problem? - ---Answes-----Bitter taste is typically considered important for preventing ingestion of toxic molecules. If the person detects something is bitter they don't need to necessarily discriminate it because the body assumes it is toxic and shouldn't be ingested

Taste receptors, esp for bitter and sweet, are found in the gut.What is their purpose? Suppose that because of a mutation sweet receptors were not expressed in the gut. What might be the consequence(s) for the individual? Think about purpose 1 / 3

and go from there. - ---Answes-----The gut can release hormones according to what the receptors are detecting, such as sugar/saccharides/polyols. Regulate insulin release The gut would not be able to detect sugar levels so it could not release insulin. Unable to regulate high blood glucose levels

Give an example of an observation or experiment that shows a role for taste receptors in immunity. Explain the observation or example. - ---Answes-----The number of tuft cells in the gut increases with infections with protozoans Taste receptors are necessary for tuft cell increase Experiement shows that with Gustducin, in infected gut, no tuft cells When transduction of taste receptors is inhibited (remove Trpm5), the amount of tuft cells, white blood cells, goblet cells is the same as wild type without infection. This shows that you need taste receptors to increase the immune response

Carefully review the anatomical organization of the outer,

middle and inner ear. - ---Answes-----Outer ear: Auricle to

ear canal

Middle ear: Ear drum with ossicles

Inner ear: Cochlea - 3 fluid filled section, Organ of Corti sits

atop the basilar membrane, tectoral membrane rests above hair cells on Organ of Corti

Explain what the tympanum does and how it contributes to the characteristics of sound that we perceive. - ---Answes----- 2 / 3

"Ear drum" sound waves vibrate it at certain amplitude, causing it to send vibrations to ossicles

Explain what the ossicles do and how they contribute to the characteristics of sound that we perceive - ---Answes----- Most of sound bounces off of liquid, going from 2 air filled compartments you need the bones to increase the force going from a big area to small area in order to move fluid and maintain the amplitude or reduce a loud sound

Explain what the oval and round windows do and how they contribute to the characteristics of sound that we perceive - -- -Answes-----The stapes pushes on oval window which pushes the inner ear fluid which is not compressible. Need round window to allow fluid movement and a pressure change

Explain what the basilar membrane does and how it contributes to the characteristics of sound that we perceive - - --Answes-----The base of the Organ of Corti, vibrates in response to a sound which allows the Organ of Corti and Tectoral membrane to move and bend hair cells, detects frequency of sound

Explain what the Organ of Corti does and how it contributes to the characteristics of sound that we perceive - ---Answes---- -Contains hair cells innervated by afferent nerve fibers that carry info to the brain

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