Human Anatomy: The Ear
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Questions and Answers

Which artery supplies the outer surface of the tympanic membrane and the anterior portion of the tympanic cavity?

  • Deep auricular artery
  • Anterior tympanic artery (correct)
  • Superficial temporal artery
  • Posterior auricular artery

    • Which artery supplies the tensor tympani and its bony canal?

  • Superior tympanic artery (correct)
  • Caroticotympanic branch of the internal carotid artery
  • Anterior tympanic artery
  • Inferior tympanic artery

    • Which artery supplies the cochlear and vestibular structures?

  • Posterior auricular artery
  • Anterior tympanic artery
  • Caroticotympanic branch of the internal carotid artery
  • Labyrinthine artery (correct)

    • Which artery supplies the inner surface of the tympanic membrane?

    <p>Posterior auricular artery</p> Signup and view all the answers

    Which artery supplies the medial walls of the tympanic cavity?

    <p>Inferior tympanic artery</p> Signup and view all the answers

    Which artery supplies the external acoustic meatus and the auricle?

    <p>Superficial temporal artery</p> Signup and view all the answers

    What is the main function of the external ear?

    <p>To collect air vibrations</p> Signup and view all the answers

    Which part of the auricle has a characteristic shape and collects air vibrations?

    <p>Auricle as a whole</p> Signup and view all the answers

    What is the length of the external auditory meatus?

    <p>2.5 cm</p> Signup and view all the answers

    What is the function of the tympanic membrane?

    <p>To separate the external ear from the middle ear</p> Signup and view all the answers

    Which nerve supplies the sensory nerve supply of the skin of the external auditory meatus?

    <p>Auricular branch of the vagus nerve</p> Signup and view all the answers

    What is the composition of the middle layer of the tympanic membrane?

    <p>Fibrous with fibers attaching to the malleus</p> Signup and view all the answers

    What is the name of the depressed area between the helix and antihelix?

    <p>Scaphoid fossa</p> Signup and view all the answers

    What is the structure that extends from the face into the concha?

    <p>Tragus</p> Signup and view all the answers

    Which part of the external auditory meatus is formed by the tympanic, squamous, and petrous portion of the temporal bone?

    <p>Inner two-thirds</p> Signup and view all the answers

    What is the characteristic of the tympanic membrane?

    <p>It is a thin, semitransparent membrane</p> Signup and view all the answers

    What is the name of the structure that connects the anterior wall of the tympanic cavity to the nasal pharynx?

    <p>Eustachian tube</p> Signup and view all the answers

    What is the function of the eustachian tube?

    <p>To facilitate the exchange of air between the tympanic cavity and the nasal pharynx</p> Signup and view all the answers

    What is the name of the structure that lies behind the middle ear in the petrous part of the temporal bone?

    <p>Mastoid antrum</p> Signup and view all the answers

    What is the posterior wall of the mastoid antrum related to?

    <p>Sigmoid venous sinus and cerebellum</p> Signup and view all the answers

    What is the name of the largest ossicle?

    <p>Malleus</p> Signup and view all the answers

    What is the name of the structure that articulates with the head of the malleus?

    <p>Incus</p> Signup and view all the answers

    What is the name of the structure that separates the cochlear duct from the Scala vestibuli?

    <p>Vestibular membrane</p> Signup and view all the answers

    What is the name of the structure that is located within the cochlea and contains endolymph?

    <p>Cochlear duct</p> Signup and view all the answers

    What is the name of the structure that is responsible for maintaining the ionic composition of endolymph?

    <p>Stria vascularis</p> Signup and view all the answers

    What is the name of the sensory receptors located in the ampullae of the semicircular ducts?

    <p>Crista</p> Signup and view all the answers

    Study Notes

    The Ear

    • Maintains the balance of the body (vestibular) and perceives sound (auditory)
    • Consists of the external ear, middle ear (tympanic cavity), and internal ear (labyrinth)

    External Ear

    • Comprised of the auricle and external auditory meatus
    • Auricle:
      • Has a characteristic shape and collects air vibrations
      • Consists of a thin plate of elastic cartilage covered by skin
      • Possesses both extrinsic and intrinsic muscles supplied by the facial nerve
      • Divided into helix, antihelix, scaphoid fossa, concha, tragus, and antitragus
    • External auditory meatus:
      • Curved tube that leads from the auricle to the tympanic membrane
      • About 2.5 cm in length and conducts sound waves to the tympanic membrane
      • Lined by skin and its outer third is provided with hairs, sebaceous and ceruminous glands

    Tympanic Membrane

    • Most medial portion of the external ear that separates it from the middle ear
    • A connective tissue structure that is covered with skin on the outside and mucous membrane on the inside
    • Composed of three layers: external layer (derived from skin), middle layer (fibrous), and inner layer (continuous with the mucous membrane of the middle ear cavity)
    • Translucent and allows the structure within the middle ear to be observed during otoscopy
    • Has a handle/manubrium of malleus and anterior and posterior malleolar folds
    • Pars tensa is the tense portion of the tympanic membrane, and pars flaccida (Shrapnell's membrane) is the flaccid portion

    Middle Ear

    • Transmits sound vibrations from the tympanic membrane to the inner ear via the ear ossicles (malleus, incus, and stapes)
    • Located mainly within the petrous portion of the temporal bone
    • Resembles a biconcave lens in shape
    • Composed of the tympanic cavity that connects anteriorly with the nasopharynx via the auditory tube (eustachian tube) and mastoid air cells posteriorly
    • Contents:
      • Ear ossicles
      • Muscles: tensor tympani and stapedius
      • Nerves: chorda tympani, tympanic branch of CN IX, lesser petrosal nerve
      • Tympanic plexus: parasympathetic (CN IX), sympathetics (superior cervical ganglion via carotid plexus)

    Ear Ossicles

    • Malleus:
      • Largest ossicle that possesses a head, neck, long process/handle, anterior process, and lateral process
    • Incus:
      • Possesses a large body and two processes (long and short)
    • Stapes:
      • Smallest ossicle that possesses a head, neck, and two limbs that attach to the oval base

    Muscles of the Ossicles

    • Tensor tympani and stapedius muscles

    Auditory Tube (Eustachian Tube)

    • Connects the anterior wall of the tympanic cavity to the nasal pharynx
    • Its posterior third is bony, and its anterior two-thirds is cartilaginous
    • Serves to equalize air pressures in the tympanic cavity and the nasal pharynx

    Mastoid Antrum

    • Lies behind the middle ear in the petrous part of the temporal bone
    • Communicates with the middle ear by the aditus
    • Relations:
      • Anterior wall: related to the middle ear; contains the aditus
      • Posterior wall: separates the antrum from sigmoid venous sinus and cerebellum
      • Lateral wall: forms the floor of the suprameatal triangle
      • Medial wall: related to the posterior semicircular canal

    Inner Ear

    • Also known as the labyrinth
    • Situated in the petrous part of the temporal bone, medial to the middle ear
    • Consists of the bony labyrinth and the membranous labyrinth

    Bony (Osseous) Labyrinth

    • Located in the petrous portion of the temporal bone
    • Surrounds the membranous labyrinth
    • Contains perilymph
    • Connects to the middle ear via the fenestra vestibuli and the fenestra cochlea
    • 3 parts: vestibule, cochlea, and semicircular canals

    Membranous Labyrinth

    • Located within the osseous labyrinth
    • Contains endolymph
    • Divided into 4 parts: cochlear duct, saccule, utricle, and semicircular ducts

    Cochlear Duct

    • Spiral structure located within the cochlea
    • Triangular in shape, with a base created by the endosteum of the canal known as the spiral ligament and the stria vascularis
    • Contains sensory receptors (hair cells) and the organ of Corti

    Saccule and Utricle

    • Small structures located within the vestibule of the osseous labyrinth
    • Connected to the utricle via the utriculosaccular duct and the endolymphatic duct
    • Contain sensory receptors (maculae) that are sensitive to vertical and horizontal acceleration

    Semicircular Ducts

    • Correspond to the semicircular canals of the osseous labyrinth (anterior, posterior, and lateral)
    • Open into the utricle via 5 openings
    • Contain sensory receptors (crista) that are located in its ampullae

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    The Ear PDF

    Description

    This quiz covers the structure and functions of the human ear, including maintaining balance and perceiving sound.

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