Middle ear, Biology

Assignment Help:

MIDDLE EAR -

  1. Protected by tympanic bone. It's cavity is tympanic cavity.
  2. It is lined by simple cilliated columnar epithelium. It is connected to naso pharynx by Eustachian canal.
  3. Here valve is present, generally closed, during shouting, yawning & swallowing it is opened.
  4. Due to it on both sides of tympanum, pressure of air is equalized. Inflamation of eustachian tube is eutachitis.
  5. Cold may block the eustachian tube & the pressure outside and inside the middle ear do not equalige. So divers and fliers do not work when they have cold. Outside preesure is increases in diving & decresed in flying.
  6. Middle ear is connected to internal ear by fenestra ovalis or oval window and fenestra rotundus or round window.
  7. By fenestra ovalis sound waves enter in to internal ear. By fenestra rotundus sound waves come out if strong.
  8. Between tympanum and fenestra ovalis there is a chain of 3 bones collectively called as ear ossicles.
  9. Three bones are malleus, inchus & stapes. Malleus is hammer shaped attached to tympanum.
  10. Inchus is anvil shaped. Stapes is stirrup shaped, smallest bone with bone marrow.
  11. All bone are articuluted by hinge joint & fixed in position due to their respective ligaments.
  12. These bones are modification of articular, quadrate and hyomendibular.
  13. In frog collumella auris present, which is modification of hyomendibular.
  14. Ear ossicles transmit the vibration from the tympanic membrane to internal ear and also amplify them about 20 times.
  15. Two small muscles tensor tympani and stapedius, joined to malleus and stapes respectively, contract to prevent damage to the dellicate internal ear at the time of loud sound.

Related Discussions:- Middle ear

Formation of gametes, In his experiments, Mendel noted that when two traits...

In his experiments, Mendel noted that when two traits are involved in a genetic cross, they are inherited independently of each other. The reason for this is that A. genes on the s

How are the female gametes of gymnosperms formed, Q. How are the female gam...

Q. How are the female gametes of gymnosperms formed? What is the relationship between this process and the concept of alternation of generations? In the female strobiles (cones

Define the clinical manifestations of underweight, Define the Clinical Mani...

Define the Clinical Manifestations of Underweight? Underweight may predispose to fatigue, lethargy and breathlessness. Iron-deficiency anaemia is usually seen because the diet

What happens to the dna molecule when the ends, Now try to pull the strands...

Now try to pull the strands apart at the "origin of replication." What happens to the DNA molecule when the ends are restricted

Importance of behaviour change communication, Importance of Behaviour Chang...

Importance of Behaviour Change Communication BCC is an in built part of a diabetes prevention, care and support program. Importance of BCC: · Increase knowledge. BCC can en

Explain risk evaluation, Explain Risk  evaluation Risk  evaluation: Th...

Explain Risk  evaluation Risk  evaluation: The  risk  evaluation involves: A) identification of a food safety problem B) Establishment of a risk profile C) Ranking of

Monosaccharide sugars, Monosaccharide Sugar - carbohydrate consisting o...

Monosaccharide Sugar - carbohydrate consisting of a single sugar unit Have an aldehyde or a ketone group and 2-5 alcohol groups depending of the # of carbons

Permanent wilting percentage (pwp), Permanent Wilting Percentage (PWP) ...

Permanent Wilting Percentage (PWP) It is the percentage of moisture in the soil at which a plant wilts and does not recover unless water is added to the soil. PWP for clay is

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd