FUNCTIONS OF PARTS OF MAMMALIAN EYE

Parts of the eyes, Medicinenet.com photo credit.

1 – Optic papilla (Blind Optic/optic disc): Optic papilla is where the axon of the retina ganglion converges to form the optic nerve head.  This part of the eye has no photo receptors and their fore function as a shock absorber.

 

2 - Optic nerve: Optic nerve, this is an extension of the fore brain, it conveys afferent fibers from the ganglion cells of the retina, it pass out of the orbit through the optic canal to the chiasm,  It detect light ray and transmit visual information from the retina to the brain.

3 – Choroid: Choroid is the layer between the Sclera and the retina, It has protective tissue and supplies the outer layer of the retina with oxygen and nutrients; It contains Melanin, a pigment which absorb light ray thereby preventing internal reflection. 

4- Vitreous humor (Vitreous body): This is the fluid filled cavity between the lens and the retina; it helps to keep the eyes in position by pressing it against the choroid. It contains phagocytes which remove unwanted dirt particles from the virtual field of view. It is also concerned with hyaluronic acid production.

5 – Iris: This is the anterior division of the vascular tunic of the eyes, a diaphragm perforated in the centre (pupil) attached peripherally to the scleral spur, and it is made up of stroma and a double pigmented layer of retinal epithelium, from which the sphincter and dilator muscle are derived. 

6 – Sclera: The sclera is the outer fibrous layer enclosing the eyes, this part of the eyes maintains it shape ad help and also protect it from the external injury.

7 – Pupil: it is the opening in front of the eyes; it regulates the amount of light entering the eyes.

8 – Retina: The retina is a photo receptor found in the inner surface of the eyes, it receive light from object and transmit it to the brain for interpretation.

9 – Cilliary muscle: This keeps the lens in position.

10 – Fovea: This is the part of the eyes that is important in centra vision (Fovea visions) where it plays a crucial role in activities that requires details such as reading, driving and watching etc.  It is found in the muscular region of the retina.

11 – Lens: This is crystalline, transparent bicarbonate, structure that focuses far and distance objects.

Cornea: This part of eyes also control and focuses incoming light ray, it is transparent and non muscular and covers the iris, pupil and the anterior parts of the eyes, it is the continuation of the sclera.  Cornea protects the eyes from dust and other harmful foreign matters but combines this protective function with the eye lid, eye socket and tears.