Senses: Vision (Cow's Eye)

                The visual system consists of the eyes, accessory structures and sensory neurons. We obtain much of our information about many things through the visual system. Each parts of the eye has its functions.

                There are also functions of the eye like the light refraction and focusing Images on the retina. The important characteristic of light is that it can be bended or refracted. Light that passes through a concave surface diverges while light passing through a convex surface surges. The converging light rays cross at the focal point and are said to be focused.

                The activity that we did in vision is the dissection of the cow’s eye. The cow’s eye is somehow similar to the human eye. In dissecting the eye, we saw the different parts of it like the optic nerve, pupil, lens, cornea and many more. We also used the lens of the cow’s eye and placed it on a paper with letters. When we placed it, the letters or the text became big and the lens of the cow looks like a magnifying lens.

Here are some pictures from the activity:

Senses

                Sensation is the conscious awareness of stimuli received by sensory receptors. Sense is the ability to perceive stimuli. Senses is divided into two groups, the general and special senses.

General senses have receptors distributed over a large part of the body. They are also divided into two groups, somatic and visceral senses. The somatic senses provide information about the body and environment while the visceral senses provide information about the internal organs, pain and pressure.

Special Senses are localized to specific parts of the body. The special senses are smell, sight, hearing, and balance.

We also did an activity to test for the different special senses. First is the color blindness test, color blindness is the absence of perception of one or more colors. Color perception may be decreased or completely lost. We used the Ishihara test which consists of mosaic figures where numbers or objects are hidden. Fortunately, all of us passed this test.

Next is the Visual Acuity Test, it is a test used to determine if you could read the big and small letters from a specific distance. It could determine if you have a normal vision.  We used the Snellen chart in this test. Some of our group mates find it hard to read some small letters in the Snellen chart.

Next is the Test for hearing. We did the Weber Test and Rinne Test using the tuning fork. Weber test is a test using a vibrating tuning fork which is held various points along the midline of the skull and face while Rinne Test is a test for evaluating loss of hearing in one ear.

The last test is the knee-jerk reflex test. It is for determining the reflex of the person. We used a hammer and tap it on the patellar tendon.