Eyeball - choroid, Biology

CHOROID -

  • Thin, net like made up of connective tissue, rich in blood vessels.
  • Pigment present, red in rabbit, brown or black in man. It reduces internal reflection.
  • Except cornea this layer is attached to sclerotic.
  • In front of cornea this layer froms a thin coloured partition i.e. iris. IRIS -
  • It is perforated in the middle by an aperture pupil. Iris is highly muscular
  • Circular and radial muscles are present. Circular muscles are sphincter type. Radial muscles are dilator type.
  • On contraction of circular muscles diameter of pupil is reduced it is myosis, it takes place in sharp light.
  • On contraction of radial muscles diameter of pupil is increased, it is mydriosis, it occurs in dimlight.
  • Atropine is used to dialate pupil.

2037_choroid.png

  • Basal part of iris is highly muscular having circular, radial and obligue muscles. It is known as cilliary body.
  • On its free surface 70 - 80 cilliary processes present secretes aquous humour in aquous chamber.
  • Cilliary body also affects convexity of lens.

1261_choroid1.png

Posted Date: 10/3/2012 4:13:10 AM | Location : United States







Related Discussions:- Eyeball - choroid, Assignment Help, Ask Question on Eyeball - choroid, Get Answer, Expert's Help, Eyeball - choroid Discussions

Write discussion on Eyeball - choroid
Your posts are moderated
Related Questions
A mother has brought her 2-week-old infant to the emergency department due to the baby's persistent and increasing jaundice. Blood testing reveals that the infant's unconjugated bi

How do the availability of water and light and the climate affect the growth of a population? The availability of water and light and the climate are abiotic factors that limi

What happens when auxin concentration in some structures of the plant is over the action range of the hormone? In some of parts of the plant (roots, stem, lateral buds) there a

Q. Can you explain Likar System with Electrodes? The 12 lead Mason - Likar system with electrodes is used. The plastic adhesive electrodes has self contained electrode jelly in

Properties of Cardiac Cells Automatically: ability of the heart to initiate impulses regularly and spontaneously. Excitability: ability of cardiac cells to respond to

Physical Stress - Temperature We are most familiar with the plants and other organisms that live at temperatures close to the temperature range in which we are adapted to live

Characteristics of the Five-Kingdom classification At present, as you know, the trend is to follow the five-kingdom classification. However, while accepting the Five-Kingdom C

Define Sit and Reach Flexibility component in the humans? The subject sits on a mat with legs extended straight ahead. Legs should be at right angles to a taped the r box, with

What are the precautions to be taken when harvesting autogenous bone grafts from mandibular symphysis and ramus? When harvesting grafts from the mandibular symphysis region, fo

Explain amino acid composition In terms of amino acid composition, high radiation doses such as those required for sterilization (e.g. 25-27Kgy), do not change the content of c