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

Nutrition, list and explain the modes of nutrition

list and explain the modes of nutrition

Vasodilatation from the time of injury, The blood vessels surrounding an ac...

The blood vessels surrounding an acutely inflamed site usually represent progressive vasodilatation from the time of injury.

Define points to remember regarding to food processing, Define Points to Re...

Define Points to Remember regarding to Food Processing? 1. Conversion of raw materials and ingredients into acceptable consumer products is referred to food processing, which c

Types of polysaccharides on the basis of functionality, FUNCTIONAL L Y PO...

FUNCTIONAL L Y POLYSACCHARIDES ARE OF THREE TYPES - Storage, Structural, Mucopolysaccharides Storag e polysaccharides function as reserve food which can be hydrolyzed

Investigation of tricuspid regurgitation by echo doppler, Q. Investigation ...

Q. Investigation of Tricuspid regurgitation by Echo Doppler? Investigations ECG in secondary TR shows evidence of right atrial overload and right ventricular hypertrophy

Define role in protein metabolism and growth, Define Role in protein metabo...

Define Role in protein metabolism and growth? Severe vitamin A deficiency results in abnormal RNA metabolism and protein synthesis and hence interferes with growth. Hence vitam

Animal diversity, why obelia is of special interest in zoology

why obelia is of special interest in zoology

Define requirements of calcium during pregnancy period, Define requirements...

Define requirements of Calcium during pregnancy period? The foetus retains about 25-30 g of calcium, over the course of gestation, most of which is deposited in the last trimes

Describe the nature of the polymorphism, 1. DNA damage can occur spontaneou...

1. DNA damage can occur spontaneously or be induced by external factors. Describe the types of DNA damage caused by external factors and how they are repaired in prokaryotes and eu

Causes of apomixis, Causes of Apomixis Apomictic species are generall...

Causes of Apomixis Apomictic species are generally hybrids or polyploids, as a consequence, there is irregular meiosis. Apomixis appears to be controlled by a set of genes. T

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