External ear, Biology

EXTERNAL EAR -

  1. It is an oval shaped, some what funnel like, skin covered flap of elastic cartilage and muscles.
  2. It's outer stiff ridge is called hellix. Lower flexible lobe is lobule. Cavity is known as auricle or Concha.
  3. It collects sound waves and direct them to canal i.e. external auditory meatus.
  4. It is trumpet shaped in rabbit. Situated on lateral side of head part.
  5. Immovable as oticularis muscles are vestigeal, movable in rabbit.
  6. External auditory meatus run up to tympanum. It is 'S' shaped tube to prevent hard objects hitting the tympanum directly, in rabbit tube is long & straight.
  7. Canal is supported by elastic cartilage in the outer portion & by temporal bone in the inner portion.
  8. Outer region of canal bears hair to cheek dust particle.
  9. Inner region consists of ceruminous gland or wax gland to secreate cerumen or ear wax to protect lining of meatusĀ & tympanum.
  10. Pinnae absent in platypus, whales seal, walrus & sea cow etc.
  11. Tympanum or tympanic membrane is thin, oval, tightly stretched on a cartilage i.e. Annular tympanicus.
  12. It is composed of connective tissue with fibres radiating from the central region called umbo.
  13. It's external part is ectodermal, middle part is mesodermal & inner part is endodermal in origin.

2348_man ear structure.png

Ear of Man

742_rabbit ear.png

Ear of Rabbit

Posted Date: 10/3/2012 2:42:33 AM | Location : United States







Related Discussions:- External ear, Assignment Help, Ask Question on External ear, Get Answer, Expert's Help, External ear Discussions

Write discussion on External ear
Your posts are moderated
Related Questions
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Chilling and Flower Induction Some plants flower only after passing a winter season. For example, winter wheat is sown in the autumn for harvest in the following summer. It ne

Determine some Food Sources of chromium? Chromium occurs in trivalent form in foods. Good sources of chromium include whole grains, spices and condiments, meats especially orga

Explain the life cycle of Water? The water cycle , or hydrologic cycle, is one of the most important processes to living organisms on Earth. Consider the following facts:

What is the structural difference between plasmalogen and other glycerophospholipids? What physiological advantage arises from this structural difference?

Pectin The word pectin is derived from a Greek word which means to "congeal or solidify". Pectin is an acidic structural polysaccharide, found in fruit and vegetables and mainl

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Which are the organs that are part of the musculoskeletal system? The main organs and tissues that are part of the musculoskeletal system in humans are the cartilages, the bone

Q. Explain about Long acting insulin? Long acting: Long acting insulin does not work until 4 Lo 8 hours after injecting. Its peak activity occurs 18 to 24 hours after injectio

Q. What are vitamins? What are the major vitamins needed by humans? Most vitamins are coenzymes fundamental substances for the enzyme functioning that are not produced by the o