Welcome to Zoology World

balindrakumar033@gmail.com   25/11/2017,Saturday


The science or study of animal life. Together with botany, the study of plant life, it forms the science of biology. Zoology is such a vast subject that most zoologists specialize or focus on the study of particular organisms or taxonomic groups. tion of animals.

Eye movement

 6 extrinsic muscles are found in 
human being

In eye orbit eyeball remain attached with 6 extrinsic muscles. out of six,first four are rectus and last two are oblique muscles.

1.Anterior rectus or Internal rectus.

2.Posterior rectus or External rectus.

3.Inferior rectus.

4.Superior rectus.

5.Inferior oblique muscle.

6.Superior oblique muscle.

Defects of eye

1. Myopia(Short or Near-sightedness)

In myopia near object is clear

a. Near object is clear .Far object is not clear.

b. Eyeball become longer.

c. Image is formed before retina.Can be removed by concave lens.

Hypermetropia (Long or Far sightedness)

p>a. Far object is clear . Near object is not clear.

b. Eyeball become short.

c. Image is formed behind the retina.

d.Can be removed by convex lens.

3. Astigmatism

Curvature of cornea 
become irregular and image is not clearly form.

a. Curvature of cornea become irregular and image is not clearly form.

b. Can be removed by clindrical lens.


It is due to defective
protein metabolism.

a. It is due to defective protein metabolism .

b. During this lens or cornea sometime both become opaque.

c. Operation is needed.


Glaucoma is caused by blockage of schlemm

It is due to increase in intraocular pressure in aqueous chamber.

Operation is needed at early stage due to blockage of schlemm's canal.

6. Trachoma

It is increased in

a. It is increased in redness of eye and more secretion of watery fluid.

b. It is due to infection of bacteria ,chlamydia trachomatis.

c. Due to this follicles may form in conjunctiva.

7. Xerophthalmia

It is due to deficiency of vitamin A(A2). During this conjunctiva or cornea becomes keratinized. It may lead to blindness.