Sense Of Vision

Question 1

Sense of vision work for eye and the brain

At least a third of the cerebral cortex is involved in processing visual information.

Answer 1

Eye anatomy and physiology and made of three layers:
• sclera = outer layer, white and fibrous
cornea= transparent region infront of the pupil.
conjunctiva = membrane that covers the scaler.
• choroid = middle layer, darkly pigmented and vascular, absorbs stray light rays.
• retina = inner layer, located in the posterior compartment.

Question 2

The choroid

Answer 2

At the front becomes the iris, iris controls the size of pupil and behind the iris, the choroid thickens into the muscular ( ciliary body). This ciliary controls the shape of the lens. This lens divides the eye into two compartments:
• anterior is infront of lens filled with (aqueous humor).
• posterior is behind the lens filled with (vitreous humor). Clear galatinoues fluid.

Question 3

The Retina/ contains photoreceptore called rods and cones

A special region, the fovea centralis that contains densely packages cone cells.

Answer 3

Function of photoreceptore:
• rods are sensitive to light but not color, important for night vision.
• cones are sensitive to different wavelengths of light and allow color vision and fine detail, active only bright light, three kinds of cells B, G, R.
The optic nerve, take visual information to the brain, leaves retina at the back of the eye( occipital).

Question 4

Function of the lens

Answer 4

• Focusing atrats with cornea and continues as light rays pass through the lens and both humors.
• Visual accommodation = focusing on near or far objects. Is made possible by the lens. For example:
When the viewing close objects lens shape controlled by ciliary body. Ciliary contracts and lens becomes very round. Lens brings the image into focus on retina, the elasticity of the lens decrease with age.

Question 5

The blind spot

Answer 5

No rods and cones are found where optic nerve exists the retina, no vision is possible

Question 6

Visual pathway to the brain

Answer 6

• The optic nerve from each eye traveling to the optic chiasma
• some axons cross over at the optic chiasma
• optic tracts traveling to the thalamus
• axons from thalamus carry impulses to the visual area within occipital lobe.