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

Minerals and trace elements, Minerals and Trace Elements Oxygen, carbo...

Minerals and Trace Elements Oxygen, carbon, hydrogen and nitrogen are the most common elements that make up 96% of the total weight of a mammal. The next most abundant element

In which phase of the cell cycle does the dna duplicate, Q How are the conc...

Q How are the concepts of chromosome, chromatids and chromatin related? In which phase of the cell cycle does the DNA duplicate? Chromatin is a set of filamentous the DNA molec

Name three characteristics of mitochondria, Name three characteristics of m...

Name three characteristics of mitochondria and chloroplasts that support the endosymbiotic hypothesis of eukaryotic evolution. Both organelles replicate independently of the ce

What is the phenomenon of apical dominance in plants, What is the phenomeno...

What is the phenomenon of apical dominance in plants? How can it be artificially eliminated? Apical dominance is the phenomenon by which high (over the positive range limit) au

Cytokinins - plant growth substances, Cytokinins - Plant Growth Substances ...

Cytokinins - Plant Growth Substances Folke Skoog observed that the cell division or differentiation is affected by AMP and other purines. A nucleic acid from yeast was also fo

Anatomy in relation to taxonomy, Q. Anatomy in relation to taxonomy? Th...

Q. Anatomy in relation to taxonomy? The use of anatomical* characters in taxonomy began with the development of the microscope which provided the biologist a new tool to observ

Explain treatment options for ailing and failing implants, Treatment option...

Treatment options for ailing and failing implants are varied. The clinician should start conservatively and progress to more aggressive therapy. The overall goal of therapy is

Explain adverse effects of atazanavir, Explain Adverse effects of Atazanavi...

Explain Adverse effects of Atazanavir  Atazanavir causes indirect hyperbilirubinemia. It has had no adverse effects on lipid profiles, but the drug's long-term effects are unkn

Principle of echocardiography, Echocardiography Utilizes principle of ultra...

Echocardiography Utilizes principle of ultrasound for visualization of heart and great vessels. It uses sound in the frequency of 1-10 MHz. As the frequency of probe increase

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