Ear Flashcards
Outer Ear
- receives sound waves
What are the structures of the outer ear ?
- Auricle or pinna
- External auditory Meatus
- Tympanic Membrane or Eardrum
Middle Ear
transmits sound waves from tympanic membrane to inner ear
What are the structures of the middle ear ?
- Tympanic Cavity
- Auditory or Eustachian Tube
- Auditory Ossicles
Oval and round windows
What does the auditory ossicles consist of ?
- malleus, incus, and stapes
Inner Ear
contains the sensorineural organs
What are the structures of the inner ear bony labyrinth ?
- vestibule, semicircular canals, and cochlea
What are the structures of the inner ear membranous labyrinth ?
- its utricle, saccule, semicircular ducts, cochlear duct, maculae, cristae ampullares, and organ of corti
What is the auricle of the outer ear covered by ?
elastic cartilage
What does the external auditory meatus contain?
ceruminous glands
Tympanic Cavity
- air-filled space surrounded by temporal bone
What is the tympanic cavity lined with ?
endoderm derived simple squamous epithelium
Auditory or Eustachian Tube
- connects tympanic cavity to nasopharynx
What is the auditory or eustachain tube lined with ?
- ciliated pseudostratified columnar epithelium
Middle and Inner Ear Separated by two small thin membranes “
- oval and round windows
What are the two small muscles that the middle ear consists of ?
- stapedius and tensor
Bony Labyrinth
- space within temporal bone, contains perilymph fluid divided into vestibule, 3 semicircular canals, and cochlea
Membranous Labyrinth
- suspended within bony labyrinth, filled with endolymph fluid
- divided into saccule and utricle semicircular ducts, cochlear ducts
What is the receptor of the inner ear ?
- specialized receptor cells with stereocilia called hair cells
What is the difference between stereocilia and cilia ?
- long microfilaments
- long microvilli
- don’t move
- actin/myosin
What do all three receptors organs have in the inner ear ?
- sensorineural transduction system
Organ of Corti
- has a basilar membrane
- longitudinally tuned to different frequencies
Internal Ear Fluid Movement
- from vibration of the oval window causes a vibrational wave in the basilar membrane leading stimulation of the hair cells and thus a nerve impulse
Crista ampullaris
- sensor of angular motion
- hair cells project into the cupula
What stimulates the hair cells in the crista ampullaris ?
- movement of the endolymph displaces the cupula
Where is the maculae located
- saccule and utricle
What is the role of the maculae ?
- for gravity and linear acceleration
What happens in the channels when their movement toward the Kinocilium ?
- opens channels
What happens in the channels when their movement away the Kinocilium ?
- closes channels
