Human vision and function/Part 1: Perception of objects/Bovine (cow) eye dissection activity
For this activity, you will be using your observations to make inferences from the audio-visual material and your own experimentation that will enable you to consider:
- Describing the orientation within the body and central nervous system (CNS)
- Anatomy of the eye
- The refractive surfaces of the eye, including density and curvature
- Sensitivity of sensory cells within the eye
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/79/Human_anatomy_planes.jpg/220px-Human_anatomy_planes.jpg)
Watch the video Cow's Eye Dissection. Once you have watched the dissection, answer the questions below.
Orientation of structures within the body and Central Nervous System
[edit | edit source]First question to consider: Why might a systematic language be necessary to describe orientation within the body and CNS? Consider this image of the human anatomy planes. The pre-reading from topic 1 will help you answer this.
Anatomy of the eye and the refractive surfaces of the eye (including their density and curvature)
[edit | edit source]The video “Cow's Eye Dissection” demonstrates the three-dimensional structure of the cow eye; highlighting similarities & differences with the human eye.
The external structures described include the:
- cornea
- sclera
- periorbital fat
- extraocular muscle attachment
- optic nerve
The internal structures described include the:
- posterior chamber (vitreous humour & tapetum)
- anterior chamber (aqueous humour, ciliary body & iris)
The functions of the lens are demonstrated:
- magnification of print
- accommodation (increasing curvature of the lens)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/43/Calf-Eye-Anterior-With-Vitrious-Humor-2005-Oct-13.jpg/400px-Calf-Eye-Anterior-With-Vitrious-Humor-2005-Oct-13.jpg)
Questions
[edit | edit source]Answer the following questions after watching the video:
- What are the horizontal & vertical dimensions of the cow eye and how do they differ from the human eye?
- Which structures are found at the front (ventral) surface of the eye?
- The sclera is opaque and the cornea and lens are transparent. Why is this the case?
- Describe the shape and anatomical position of the lens. What could happen if the lens is not transparent?
- How will the shape of the lens influence refraction of light through the eye and why is the print magnified through the lens??