Explain the dark adaptation of vitamin a, Biology

Assignment Help:

Explain the Dark Adaptation of Vitamin A?

In the early stages of VAD, the individual cannot see objects in dim light. This' phenomenon is used as a criterion for assessment in the dark adaptation test. The subject is either kept in a dark room for some time and asked to identify an object which is dimly illuminated, the intensity of light being increased till the subject is able to see the object (or) he is exposed to bright light for some time, by which the visual purple is bleached. The time required for the rhodopsin to be regenerated is measured by the ability to see a dimly illuminated object. Longer time taken to identify the objects is indicative of variable stages of vitamin A deficiency.


Related Discussions:- Explain the dark adaptation of vitamin a

What do you mean by ventricular arrhythmias, Q. What do you mean by Ventric...

Q. What do you mean by Ventricular Arrhythmias? Considerable disagreement exists regarding the significance of resting ventricular ectopic beats. In study comparing the coronar

Name an artificial fertiliser which farmers can use, Name an artificial fer...

Name an artificial fertiliser or fertilisers which farmers can use to increase the supply of nitrate, phosphate and potassium to their crops.   NPK compound fertiliser havin

What are the main symptoms of the pulmonary, What are the main symptoms of ...

What are the main symptoms of the pulmonary and of the intestinal phases of the ascaris infestation? In the pulmonary stage the ascaris infestation causes cough, hemoptysis, dy

Which keel is characteristic of the flowers, Keel is characteristic of the...

Keel is characteristic of the flowers of : 1. Gulmohur 2. Cassia 3. Calotropis 4.  Bean Bean

Describe different animal groups, Describe different animal groups a) C...

Describe different animal groups a) Could  comprehensively  compare  and  contrast  the  behaviours  exhibited  by  social animals rather than describe different animal groups

What were coopers views on nature, What were coopers views on nature (parti...

What were coopers views on nature (particularly in regard to human progress and resource use)? And Is there any thought about rights of nature or conservation of resources in her w

What is population density, What is population density? Population dens...

What is population density? Population density is the relation among the number of individuals of a population and the area or volume they occupy. For instance, in 2001 the hum

Factors responsible for food spoilage, Q. Can you explain Factors responsib...

Q. Can you explain Factors responsible for food spoilage? Spoilage, as you would realize, is quite a natural phenomenon. All foods undergo varying degrees of deterioration or s

Differences among nematodes and annelids, What are the morphological simila...

What are the morphological similarities and differences among nematodes and annelids? Nematodes, like annelids, have a cylindrical elongated body. Annelids differentiate from

What are the destinations of those oxygen atoms, Photosynthesis is the most...

Photosynthesis is the most significant producer of molecular oxygen (O2) on our planet. From which molecule do oxygen atoms liberated by photosynthesis come? From which other molec

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