Ear Anatomy Quiz: Outer and Middle Ear Structures

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Questions and Answers

What type of cartilage is the pinna made of?

Elastic cartilage (correct)

Fibrocartilage

Ciliginous cartilage

Hyaline cartilage

What is the function of the stapedius muscle in the middle ear?

To amplify sound waves

To transmit sound vibrations to the inner ear

To relieve tension on ossicles during loud noises (correct)

To regulate the flow of perilymph in the inner ear

What is the name of the tube that connects the middle ear to the nasopharynx?

Eustachian tube (correct)

Tympanic tube

Nasopharyngeal tube

Auditory tube

What is the name of the structure that separates the outer ear from the middle ear?

Tympanic membrane (A) Signup and view all the answers

What are the three middle ear ossicles joined together?

Malleus, Incus, and Stapes (B) Signup and view all the answers

What is the fluid that fills the membranous labyrinth in the inner ear?

Endolymph (C) Signup and view all the answers

Which part of the cochlea is filled with perilymph and abuts the oval window?

Scala vestibuli (D) Signup and view all the answers

What is the function of the maculae in the utricle and saccule?

To respond to static equilibrium and linear acceleration (A) Signup and view all the answers

Which structure houses the saccule and utricle?

Vestibule (A) Signup and view all the answers

What is the name of the structure that contains the receptor cells for angular rotation?

Crista ampullaris (A) Signup and view all the answers

Which nerve is responsible for transmitting signals from the cochlea to the CNS for hearing?

CN-VIII (B) Signup and view all the answers

What is the name of the structure that connects the scala vestibuli and scala tympani at the apex of the cochlea?

Heliocotrema (A) Signup and view all the answers

What is the main function of the semicircular ducts and Crista Ampullaris?

Detect angular rotation and dynamic equilibrium (D) Signup and view all the answers

Which of the following is NOT an accessory structure of the eye?

Extrinsic eye muscles (D) Signup and view all the answers

What percentage of the cerebral cortex is involved in processing visual perception?

40% (D) Signup and view all the answers

What is the function of the tarsal glands in the eyelids?

Secrete oily substance to keep eyes moist (A) Signup and view all the answers

What is the main function of the levator palpebrae muscle?

Raises and lowers eye lids (C) Signup and view all the answers

What do the eyelashes help to prevent?

Substances from entering the eye (D) Signup and view all the answers

Study Notes

Outer Ear Anatomy

Pinna (auricle) is covered with skin and made of elastic cartilage, consisting of the helix and lobule
External auditory meatus (ear canal) is lined with skin and ceruminous glands and passes through the temporal bone

Tympanic Membrane

Separates the outer ear from the middle ear
Innervated with sensory fibers from the trigeminal and vagus nerves
Responds to air vibrations or sound waves and transfers energy to the middle ear ossicles

Middle Ear Anatomy

Consists of three middle ear ossicles: malleus, incus, and stapes
Malleus (hammer) attaches to the tympanic membrane and is connected to the incus
Incus (anvil) is connected to the stapes
Stapes (stirrup) footplate attaches to the oval window of the inner ear, creating ossiculations in the scala vestibuli
Middle ear muscles: stapedius inserts on the stapes, and tensor tympani inserts on the malleus
Eustachian tube connects the middle ear to the nasopharynx

Inner Ear Anatomy

Housed in a maze of temporal bone passages called the bony labyrinth
Bony labyrinth is filled with perilymph and is lined with periosteum
Bony labyrinth consists of:
- Vestibule
- Cochlea
- Semicircular canals
Membranous labyrinth lines inside the bony labyrinth
Lined with epithelium and is filled with endolymph (high in Na+, K+)

Structures of Hearing

Cochlea: a spiraling chamber of the bony labyrinth, lined with a membranous labyrinth with 3 separate chambers
- Scala vestibuli (filled with perilymph) abuts the oval window
- Cochlear duct (filled with endolymph) contains the organ of Corti
- Scala tympani (filled with perilymph) abuts the round window
Organ of Corti: innervated by CN-VIII, the cochlear portion of the VIII pathway to the CNS for hearing

Structures of Equilibrium

Vestibule houses the saccule and utricle, which each contain a macula that are receptor cells for:
- Static equilibrium (head position when still)
- Linear acceleration (head movements in a straight line)
Semicircular canals are lined with a membranous semicircular duct, with an ampulla at each end containing a crista ampullaris
Receptors detect:
- Angular rotation (head rotation)
- Dynamic equilibrium

The Eye and Vision

Visual receptors account for ~ 70% of all sensory input in the body
40% of the cerebral cortex is involved in processing visual perception
Eye balls are the sense organs for vision

Accessory Structures of the Eye

Eyebrows
Eyelids with tarsal and ciliary glands
Eyelashes
Lateral and medial canthus (angles at the corner of the eye)
Conjunctiva
Lacrimal apparatus
Extrinsic eye muscles (6)

Eye Accessory Structures

Eyelids (palpebrae) protect the eyes from foreign objects and bright light
Conjunctiva: a transparent mucous membrane covering the inner surface of the eyelids and anterior surface of the eye, but not the cornea

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Description

Test your knowledge on the anatomy of the outer and middle ear. Learn about the structures like Pinna, External Auditory Meatus, and Tympanic Membrane. Explore how these components function in hearing and equilibrium.