Summary
Summary The Ear
- Course
- Life Sciences
- Institution
- 12th Grade
Summary and notes needed for grade 12, Relative to both IEB and NSC
[Show more]
Seller
Follow
Content preview
STRUCTURE: --
Middle ear is connected to pharynx by Eustachian tube.
FUNCTIONS:
Pinna
Tympanic membrane transmits sound waves to ossicles
Ossicles transmit vibrations from tympanic membrane to inner
ear
Eustachian tube maintains equal pressure on either side of ear
Auditory nerve drum.
Oval window transmits vibrations of ossicles to inner ear.
Round window absorbs pressure set up in inner ear.
INNER EAR
- Fluid-filled cavity made up of bony labyrinth & membranous labyrinth.
- Bony labyrinth → filled with perilymph
- Membranous labyrinth → made of membranous sacs & tubes that float
around in the perilymph (semi-circular canals; sacculus; cochlea); filled
OUTER EAR with endolymph
- Cartilaginous pinna → directs sound waves through auditory canal - Membranous cochlea (within bony cochlea) has 3 canals:
towards tympanic membrane) o Upper canal (filled with perilymph)
- Auditory canal → conducts sound waves to tympanic membrane; cerumen o Middle canal (filled with endolymph)
/ wax & hairs found in it prevent entrance of small organisms; wax o Lower canal (filled with perilymph)
prevents drying out of ear drum. - FUNCTIONS:
Semi-circular canals, sacculus & utriculus → concerned with
MIDDLE EAR balance & equilibrium of the body.
- Air-filled cavity within the skull, separated from outer ear by tympanic Cochlea contains organ of Corti → converts stimulus of sound
membrane & separated from inner ear by oval window and round window. into an impulse.
- 3 bones (ossicles) → hammer (malleus); anvil (incus) & stirrup (stapes). Auditory nerve arising from cochlea transmits sound impulse to
- Hammer is attached to tympanic membrane; stirrup is attached to oval brain.
window & anvil lies between hammer & stirrup.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller moeadam. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R80,00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79976 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 14 years now