Lecture 80 - Auditory System Flashcards
The bony ossicles of the Middle ear amplify sound by up to 200 times. Attached to the Malleus is the _____ _____ muscle, innervated by CN____. Attached to the Stapes is the ______ muscle, innervated by CN____. Both of these muscles help protect against damage from intense sounds.
Tensor Tympani muscle
CN V
Stapedeus muscle
CN VII
The ________ is the area at the tip of the cochlea that separates the Scala ______ from the Scala _______. Between these two lies the Scala media. In which of these parts of the Choclea is sound perceived?
Scala Vestibuli
Scala Tympani
Sound is perceived in the Scala Media
The Lymph in the Scala Vestibuli and Scala Tympani is high in ______, resembling plasma, while the Lymph in the Scala Media is high in ______. This ion difference lends itself to the generation and propagation of APs.
Na+
K+
Outer hair cells in the Organ of Corti ARE connected to the Tectorial Membrane, while the inner hair cells are NOT.
Which type of Stereocilia do each posses?
Which hair cells are detectors of sound quality and which are sound amplifiers?
Inner hair cells have straight stereocilia, while Outer hair cells have crescent stereocilia.
Inner –> sound quality
Outer –> amplify sound
Auditory impulses travel along the Cochlear nerve to the Cochlear nuclei located laterally at the boarder of the _____ and ______. The signal travels through the Lateral ______ to the Midbrain where it reaches the Inferior _______. From there, the signal travels to the ______ Geniculate Nucleus of the Thalamus and out to the Superior Temporal lobe.
Pons
Medulla
Lateral Lemniscus
Inferior Colliculus
Medial Genicaulate Nucleus
The Cochlear nuclei at the Pontomedullary junction are divided into Ventral and Doral.
Which is involved with detecting the Loudness of sound and helps to Localize sound along with the Olivary Nuclei?
Which is invovled with detecting frequencies?
Ventral detects loudness and helps localize
Keep in mind the Superior Olives in the Medulla help to Localize sound via their connections to each other and their connections to the Ventral Cochlear Nucleus on the ________ (ipsilater or contralateral?) side. These connections are collectively called the ______ body. Remember the ______ Cochlear Nuclei do NOT synapse with the Superior Olives.
Contralateral
Trapezoid body
Dorsal Cochlear nuclei
Keep in mind the tonotopy of the auditory pathway.
Which frequencies are projected to superficial areas of the Auditory cortex and which are projected deeper?
High frequency –> Superficial
Low frequency –> Deeper
The Superior Olive has a small number of fibers projecting to the ______ nucleus (CN ____), which allows for contraction of the Stapedius muscle and thus dampening of sound.
Facial Nucleus (CN VII)
Coduction hearing loss involves the _____ and _____ ear, while Sensorineural hearing loss involves the _____ ear.
Central hearing loss is extremely rare and involves lesions in the Auditory cortex located in _____ gyrus of the Superior Temporal Lobe.
Outer
Middle
Inner
Heschel’s gryus
With Weber’s test, which ear will hear better in the case of Conductive hearing loss? What about Sensorineural hearing loss?
Weber’s test in Conductive –> hear better in AFFECTED ear
Weber’s in Sensorineural –> Hear better in UNaffected ear
Rinne’s test for hearing is positive with ________ (normal or abnormal?) hearing and is documented as ____>____.
If it is negative, it is documented as _____>_____.
Normal
AC > BC
BC > AC
Patients with ______ (conductive or sensorineural?) hearing loss often experience Tinnitus in tandem with the hearing loss. Audiograms in these patients reveal loss of _____ recognition that is out of proportion to the associated tone deafness. These patients typically have difficulty with _____ (high or low?) pitched sounds and vowels.
Sensorineural
Speech recognition
High pitched
Vestibular _______ are typically Bilateral in patients with _________ type 2. They arise at the ______ angle and result in hearing loss, tinnitus, episodic vertigo, facial weakness, absent corneal reflex, and ataxia.
Vestibular Schwannomas
Neurofibromatosis Type 2 (NF 2)
Cerebellopontine angle
Lesions to the AUditory cortex typically result in impairment in the ability to ______ sound.
Localize
Conductive hearling loss will show intact _____ signals but abnormal _____ signals on audiogram.
Bone
Air
Keep in mind this means you’ll need greater decibels to hear via air conduction.
Sensorineural Hearing loss will show similar abnormal readings for both Bone and Air conduction, typically around ____- ____Hz (which is usually the frequency we hear best at).
1000 - 3000Hz
