Eye lens, Biology

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.
Posted Date: 10/3/2012 4:20:14 AM | Location : United States







Related Discussions:- Eye lens, Assignment Help, Ask Question on Eye lens, Get Answer, Expert's Help, Eye lens Discussions

Write discussion on Eye lens
Your posts are moderated
Related Questions
Coronal Disassembly - If the existing restoration with marginal defect: - The crown was sectioned through the bucco-occlusaly , Christensen crown remover elevate and remove

Menstrual cycle in human beings: 1) The cycle of changes in the female reproductive system that leads to formation of Ovum is called 'menstrual cycle'. It occurs once in 28 to

Q. What is the difference between vital and natural amino acids? Essential amino acids are those that the organism is not capable to synthesize and that need to be ingested by

ELECTRON TRANSPORT CHAIN All processes require energy. In living cells, we constantly use energy for a number of biochemical reactions e.g. muscular movements, synthesis  of ne


Phytochrome - Floral Induction Phytochrome a pigment that exists in two different inter convertible forms was discovered by Hendricks and Borthwrick et. al. and was chemically

explain the digestive system with slides because i want to prepare this topic for CSS examination

Define observation or inference for picric acid test? 1. A mahogany red colour will be seen. The mahogany red colour indicates the presence of reducing sugar. All monosaccharid

Define Drug Effects on Food Intake - gastro intestinal tract? Affect the gastro intestinal tract: Gastrointestinal irritation and ulceration are serious problems with many drug

What is Manifest Squint (Heterotropia) Manifest squint is a deviation of one eye from the normal position when the fusion reflex is present. The subcategories of manifest squin