Term
| What is the technical term for the ear? |
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Definition
| -vestibule-cochlear apparatus |
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Term
| What are the responsibilities of the ear? |
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Definition
-balance and hearing
-it is an interesting amalgam of cutaneous, bony, and specialized sensory structures designed to detect sound and movement |
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Term
| What are the 3 main division to the ear? |
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Definition
-internal
-middle
-external |
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Term
| Describe the Internal Ear. |
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Definition
| -membranous labyrinth that is an epi-lined, multi-compartment, tubular structure derived from the otic vesicle |
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Term
| The ______ that surrounds the membranous labyrinth forms that cartilage model that eventually become the _______ of the temporal bone. |
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Definition
-mesenchyme
-petrous portion |
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Term
| Definition: Bony Labyrinth of the Ear |
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Definition
-comparable cavities that surround the membranous labyrinth
-represent a fluid-filled space not lined by epi |
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Term
| What are the bony labyrinth compartments of the internal ear? What are the 3 accompanied membranous labyrinth compartments? |
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Definition
-rostral cochlea, middle vestibule, and caudal semicircular canals
-cochlear duct in the cochlea, sacculus and utriculus in the vestibule and the membranous ampullated semicircular canals |
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Term
| What are the sensory portions of the membraneous structures of the internal ear? |
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Definition
-spiral organ (formerly organ of Corti) of the cochlear duct
-saccular and utricular maculae
-cristae ampullaris of the semicircular canal |
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Term
| True or False: All sensory organs of the ear contain hair cells. |
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Definition
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Term
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Definition
| -specialized hair cells with apical stereocilia (not hair) that depolarize or hyperpolarize relative to the direction of their deflection (in other words, hair cells are tiny cellular mechanoreceptors) transduce fluid sound waves into electrical impulses |
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Term
| Hair cells have afferent and efferent innervation provided by the _______ nerve (CN _____). The nerve enters the petrous portion of the temporal bone through the _____________, sending the _________ portion caudally to the vestibule and ampullae of the semicircular canals and the _________ br to the spiral organ through the center of the cochlea called the ________. |
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Definition
-vestibulocochlear nerve
-VIII
-internal acoustic meatus
-vestibular
-cochlear
-modiolus |
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Term
| Definition: Cochlea of the Ear |
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Definition
| -highly coiled tubular structure located rostrally in the petrous portion of the temporal bone |
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Term
| The cochlea comprises a triangular-shaped, otic vesicle-derived, central, closed-end tube called the ___________. The _______ separates this compartment from the _________ of the bony labyrinth and the _______ separates the cochlear duct from the ______. |
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Definition
-cochlear duct
-vestibular mem
-scala vestibule
-basilar mem
-scala tympani |
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Term
| The scala vestibule and scala tympani are a single tube that connect at a hairpin loop at the apex of the cochlea directly connected by the _______. |
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Definition
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Term
| Fluid in the membranous labyrinth is called _______ and is high in _____. |
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Definition
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Term
| The outer wall of the cochlear duct contains the _______, a specialized structure believed to be the primary source of _______. |
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Definition
-stria vascularis
-endolymph |
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Term
| What are the 3 layers of the outer wall of the cochlear duct? Describe the contents of each. |
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Definition
-Marginal cells: otic-vesicle-derived epi cells; mitochondria-rich; specialized apical K+ channels
-Intermediate cells: neural cret-derived melanocytes- critical though unknown function in recycling K+; interconnected with epi cells and mesenchymal cells by gap junctions
-Outer basal cells: tight junctions with surrounding cells |
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Term
| The hypotenuse of the cochlear duct triangle is the ______, a very thin membrane composed of an inner lining of ______. |
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Definition
-vestibular mem
-epi cells |
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Term
| The vase of the triangle of the cochlear duct is made of a combination of the _______, ______, and ______. The ________ sits atop the basilar mem. |
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Definition
-basilar mem, spiral lamina, and osseous lamina
-basilar mem |
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Term
| The third side of the triangle of the cochlear duct has the _______ which is anchored in place by the _______. |
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Definition
-stria vascularis
-spiral ligament |
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Term
| True or False: All cells lining the cochlear duct are interconnected by tight junctions. |
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Definition
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Term
| Describe the specialized hair cells atop the basilar mem of the Organ of Corti. |
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Definition
-Outer hair cells: 3 continuous rows, running length of the cochlea
-Inner hair cells: 1 continuous row |
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Term
| What is the purpose of the apical stereocilia/basilar connections of the inner and outer hair cells on the spiral organ? |
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Definition
| -connect to phalangeal cells (Deiter's cells) that directly connect ot the basilar mem |
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Term
| What is the function of the inner and outer pillar cells in the organ of Corti? |
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Definition
| -form a stiff triangular tunnel that acts as a fulcrum for the deflection of the basilar mem and about which hair cells are oriented |
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Term
| Having over the hair cells in the spiral organ is the _________, a gelatinous appendage within which ______ of the outer hair cells embed. |
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Definition
-tectorial mem
-stereocilia |
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Term
| Describe the basilar mem of the organ of Corti. What is its functional significance? |
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Definition
-fibrous mem that varies in thickness and width within the cochlea, being shorter and thicker towards the basal end of the cochlea an dlonger and thinner towards the apical portion of the cochlea
-correlates to high frequency sound detection in the basal hair cells and low frequency sound detected in the apical hair clls |
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Term
| What is the functional significance of the location of hair cells in the Organ of Corti? |
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Definition
| -the locations of the hair cells in the cochlea reflex a specific defined frequency renge that is also correlated with a specific sensory region in the auditory cortex of the brain |
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Term
| True or False: In the spiral organ, most of the efferent nerve connections are the outer har cells whereas most of the afferent nerve connections connect with the inner hair cells. |
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Definition
| FALSE; most efferent nerve connections are to the inner hair cells whereas most of the afferent nerve connections connect with the outer har cells. |
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Term
| The middle portion of the inner ear houses two dilated membranous labyrinthine sacs knows as the _______ and _______. Similar to the cochlear duct, they are connected and filled with ______. |
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Definition
-Sacculus
-Utriculus
-endolymph |
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Term
| The sacculus and utriculus are lined with _______ epi except for the sensor region, the ______. |
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Definition
-simple cuboidal epi
-macula |
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Term
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Definition
| -a region that contains specialized hair cells with apical cilia that are embedded in a gelatinous material on which are small otoliths |
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Term
| What are the major difference between the sacculus and utriculus of the vestibule? |
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Definition
| -saccular macula is oriented in the ventrical plane whereas the utrical macula is oriented in the horizontal plane |
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Term
| What is the function of the vestibule of the ear? |
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Definition
| -detection of static position of the head, especially in the dark or under water. |
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Term
| The semicircular canals are buried within the petrous portion of the temporal cone and are oriented _______ to each other. Both ends of these tubes are in direct communication with the ________. |
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Definition
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Term
| At one end of the semicircular canals, each possesses a dilated region known as the _____. In this area, there is a conical appendage called the __________. |
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Definition
-ampulla
-crista ampullaris |
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Term
| On the surface of the crista are sensory hair cells that are embedded in a gelatinous glycoprotein struction known as the ______. As in other regions, distortion of the apical stereocilia translate into ________ and ______. |
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Definition
-cupula
-APs
-detection of motion |
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Term
| What are the functions of the semicircular canals in the ears? |
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Definition
| -sudden movements result in movement of the cupula due to inertia of the semicircular endolymph. the crista are mainly concerned with change in direction and rate of movement but once in a state of constant motion, the crista regain a state of homeostasis. |
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Term
| The _________ and _________ (or branchial arches) are primitive mesenchymal aggregates each containing vascular, neural, and CT mesenchyme. |
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Definition
| -first and second pharyngeal arches |
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Term
| Bilateral outpouchings of the developing endodermal tube develop between the first and second arches, the ___________, that is the ________ and __________. |
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Definition
-first pharyngeal pouch
-auditory tube
-middle ear |
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Term
| The first pharyngeal groove develops as an invagination from the ______ between the two pharyngeal arches. This groove becomes the ___________. |
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Definition
-ectoderm
-external acoustic meatus |
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Term
| Where the inner pouch and out groove contact is the _______- and _______- derive tympanic membrane. |
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Definition
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Term
| What structures are derived from the first pharyngeal arch? |
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Definition
| -malleus and incus as well as the tensor tympani m are all derived from the first branchial arch as well as the trigeminal nerve, which serves as innervation for this m |
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Term
| What structures are derived from the second pharyngeal arch? |
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Definition
| -stapes, stapedius m, and the facial nerve |
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Term
| What structures contribute to the external ear formation? |
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Definition
-both first and second pharyngeal arch
-in form of 6 primordial auricular hillocks |
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Term
| What structures comprise the middle ear? Functions? |
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Definition
-auditory ossicles, auditory mm, nn, tympanic cavity, and tympanic bullae
-functions mechanically to transmit sound waves to internal ear as well as stabilize the middle ear P with ambient P |
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Term
| All surfaces of bone of the auditory ossicles are lined by _______ cells. In birds, there is a single bony ossicle that connects the tympanic mem with the oval window, known as ______. |
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Definition
-low cuboidal to squamous epi cells
-columella |
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Term
| What are the three bones that comprise the auditory ossicles? |
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Definition
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Term
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Definition
-the manubrium of the malleus is incorporated into the tympanic mem
-dorsally articulates with the incus to form the incudomallearis articular joint, both the incus and malleus are anchored in the dorsal epitympanic recess by ligamentous attachmens |
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Term
| Of the malleus, the rostrally facing, muscular process is the attachment point for the _________. |
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Definition
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Term
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Definition
-this ossicle bone is roughly the shape of a molar with two appendages
-the shorter appendage or short crus becomes anchored in the epitympanic recess
-longer crus has the lenticular process at its extremity which articulates with the stapes for form the inudostapedium joint |
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Term
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Definition
-ossicle bone
-ventrolaterally the head of the stapes articulates with the incus and caudodorsally has a muscular process to which the tendon of the stapedius muschle attaches
-mediodorsally, the base of the stapes is anchored in oval window by a syndesmosis connection with the petrous portion of the temporal bone |
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Term
| What is the smallest muscle in the body? |
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Definition
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Term
| What nerve innervates the stapedius m? |
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Definition
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Term
| The tendon of the staedius m extends to attach to the head of the stapes through the ______. |
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Definition
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Term
| Rostrally, the tympanic cavity communicates with the nasal cavity by the __________. |
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Definition
| -Auditory tube (aka Eustachian tube) |
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Term
| Describe the lining of the auditory tube, nasal cavity, and portion of the tympanic cavity |
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Definition
-ciliated columnar epi cells mixed with goblet cells
-low cuboidal to squamous epi cells line portions of the tympanic cavity |
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Term
| The large anatomic size differential b/n the tympanic mem and head of the stapes approximates __:__. |
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Definition
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Term
| When do tympanic mem deflections occur? Internal ear sound waves? |
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Definition
-occur in air
-occur in fluid |
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Term
| True or False: The resistance or impedance of air is MUCH higher than the impedance of perilymph. |
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Definition
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Term
| True or False: The middle ear ossicular chain is a impedance matching whereby sound waves in air become matching sound waves in fluid. |
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Definition
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Term
| Due to ________, if the tympanic cavity is small, sound waves vibrating the tympanic mem will be deflected away because the tympanic mem cannot deflect properly. Thus larger bullae help to minimize this and _______ at the mem allowing for proper tympanic mem deflection. |
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Definition
-resistance
-sound dampening |
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Term
| Definition: Tympanic bullae |
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Definition
| -prominent, ventral bony outpouching of the tympanic cavity |
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Term
| In what species is the tympanic cavity divided into multiple compartments by bony septa? Describe the epi found here. |
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Definition
-cattle, goats, camelids, and pigs
-low cuboidal to squamous |
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Term
| Which animal has the longest auditory tube? What else is structurally unique about this animal's ear? |
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Definition
-horses
-guttural pouches: highly modified rostral and ventral outpouching of the auditory tube |
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Term
| the external portion of the ear is the _______ and functions to do what? |
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Definition
-auricle/pinna
-functions to receive and direct sound towards the detection system |
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