External ear, Biology

Assignment Help:

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 meatus & 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


Related Discussions:- External ear

Plants - rapidly flowing waters, Plants - Rapidly Flowing Waters Among...

Plants - Rapidly Flowing Waters Among the plants only small, well attached forms, such as sessile algae can survive here. Thus, due to the presence of only a few plants, the n

Determine the chain in the dna molecule, Which type of chemical bond mainta...

Which type of chemical bond maintains the pairing of each chain in the DNA molecule? To produce the DNA molecule, purine bases bind to pyrimidine bases by intermolecular bonds

How different is growth according to the biotic potential, How different is...

How different is the growth according to the biotic potential of a viral population from the growth according to the biotic potential of a bacterial population? The growth cur

Energy transformation, ENERG Y TRANSFORMATION - During photosynthes...

ENERG Y TRANSFORMATION - During photosynthesis radiant energy is converted into chemical energy by green plants. In biluminiscent organisms .e.g glow worm, noctilluca &

Basic physical concepts of plant water relation, Basic Physical Concepts of...

Basic Physical Concepts of Plant Water Relation The main idea of this section is to explain the concept of chemical potential of water or water potential and the effect of var

Determine about the visual axes of eyes, Determine about the visual axes of...

Determine about the visual axes of eyes In normal eyes, the visual axes are parallel to each other in the primary position of gaze. This position is usually maintained but in t

Responding variable, what is the responding variable in catalyst to change ...

what is the responding variable in catalyst to change oil molecules

Results of monohybrid crosses, Results of Monohybrid Crosses Mendel got...

Results of Monohybrid Crosses Mendel got the following results from his monohybrid crosses :- 1.         F 1  plants produced by a cross between two plants pure for the cont

Why the vitamin niacin is a necessary component of nad, The vitamin niacin ...

The vitamin niacin is a necessary component of NAD. Niacin can be consumed in food or manufactured in the body from tryptophan, an amino acid. How would a person's ability to break

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