Eye lens, Biology

Assignment Help:

LENS - 

  1. In lumen of eye ball, a large colourless, transparent, more convex on back side, lens present covered by lens capsule.
  2. When white tissues are formed in it, it becomes less transparent. So catarect is caused.
  3. Refrective index of lens is 1.42. In lens yellow pigment present to check harmful sun rays.
  4. Lens is fixed in position.
  5. From cilliary body suspensory ligaments or zonulla of zinn are given out to keep lens in fixed position.
  6. On relaxing of suspensory ligaments, focal length of lens is reduced.
  7. Lens divides lumen into 2 unequal chambers.
  8. Anterior small aquous chamber & posterior large vitrous chamber.
  9. Aqueous chamber is filled by aquous humour (watery fluid).
  10. Vitrous chamber is filled by vitrous wharton's jelly humour (formed during development in embryo only once).
  11. Vitreous humour is dense contains 99% H O, remaining 1% vitrein protein, hyalorunic acid & collagen fibres.
  12. Vitrous humour maintains shape of eye ball by turger pressure. Around vitrous humour hyloid layer present.
  13. In retina a blind spot present where no rods & cones are present.
  14. In vitrous humour upto blind spot a hyloid canal is present.
  15. Intralocular pressure (pressure of aquous + vitrous humour) is about 20 - 25 mmHg. optical axis touches retina to a point or area i.e
  16. area centralis or yellow spot or macula lutea. Here xanthophill pigment is present.
  17. Its central part is fovea centralis.
  18. Here only cones are obliquely placed so enlarged image is formed.

Related Discussions:- Eye lens

Fragmentation and regeneration, Fragmentation and Regeneration Both t...

Fragmentation and Regeneration Both the situations mentioned above that is whether occurring naturally or accidentally, can in general, be categorized like fragmentation. Of

Categories of air pollutants, Categories of Air Pollutants From the ab...

Categories of Air Pollutants From the above list you can see that the air pollutants can be broadly classified into the following two categories: Primary Pollutants

What do you understand by metanephridia, What do you understand by Metaneph...

What do you understand by Metanephridia? An excretory-osmoregulatory organ comprising a ciliated funnel, nephrostome, connected to tubules that lead to the external nephridiopo

Write short note on ames test, Question 1 Describe any two possible mec...

Question 1 Describe any two possible mechanisms of mutagenesis 2 Explain any five functions of Endoplasmic reticulum 3 Write short note on Ames test 4 Describe the structure an

Cultural and religious values, Wildlife has influenced language, art, relig...

Wildlife has influenced language, art, religion and social customs of many societies worldwide, and wild animals figure prominently in many cultures even today. In all cultures of

Gas transportation systems in animals, Q. Oxygen comes from the environment...

Q. Oxygen comes from the environment and carbon dioxide in the end returns to the environment. How do small animals solve the problem of taking away and bringing these molecules fr

Define hydroxybenzoic acid and hydroxycinnamic acid, Define Hydroxybenzoic ...

Define Hydroxybenzoic acid and Hydroxycinnamic acid? Hydroxybenzoic acid: e.g. ellagic and gallic acids, which are hydrolyzable tannins, present in berries and nuts. Hydroxy

Synapse - nervous system, Synapse   Nervous System Structural feature ...

Synapse   Nervous System Structural feature of unique importance in the nervous tissue is the synapse. A synapse is the anatomical site at which axon terminal processes of one

Enumerate about the wisconsin card sorting test, Enumerate about the Wiscon...

Enumerate about the Wisconsin Card Sorting Test Verbal memory, non verbal memory etc. are tested through the presentation of stimuli such as verbal learning test, selective rem

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