Sheep’s Eye Dissection

Inside & Out:Taking a Closer Look

Learning Target: Anatomy and Physiology of the Eye

I Can…Compare and contrast the structures of a sheep’s eye to that of a human eye and describe the structure and function of the components of an eye.

I Will…• Dissect a preserved sheep’s eye;• Identify the external structures of the eye• Describe the function(s) of each structure

• Identify the internal structures of the eye• Describe the function(s) of each structure

• Create a side view diagram of a human eye with appropriate labels

Materials:2-person lab group

22

Lab Instructions & PowerPoint Guide

Learning Target: Anatomy and Physiology of the Eye

External Anatomy:Sclera• Tough white outer

covering of eye that protects internal structures of eye

Cornea• Clear extension of

sclera in front of the eye that allows light to enter the eye

Learning Target: Anatomy and Physiology of the Eye

External Anatomy:

Eye muscles• Attach firmly to the

eye and pull on the eyeball causing it move

Fatty tissue• Surrounds the eye to

cushion and protect it from damage

Optic nerve• Carries information from

the eye (retina) to the brain (Occipital lobe)

Learning Target: Anatomy and Physiology of the Eye

Internal Anatomy:Vitreous humor• Clear jelly-like substance• Helps hold shape of the eye• Clear to let light through• Jelly not solid so wont crack

or breakRetina• Lines the back of the eye• Location of photoreceptors• Cones – detect color (RGB)• Rods – detect light/dark (greys)

Learning Target: Anatomy and Physiology of the Eye

Blind spot/Optic disk • Point where retina leaves to

become optic nerve• No photo receptors located

there.

Tapetum • Located behind retina • Shiny and reflective • Helps animals to see in low light• NOT found in human eyes

Internal Anatomy:

Learning Target: Anatomy and Physiology of the Eye

Lens• Round, biconcave clear disk• Focuses light onto retina• Held in place by suspensory

ligament

Internal Anatomy:

Ciliary muscles• Adjust shape of lens to focus

at different distances• Short & fat• Long and thin

Learning Target: Anatomy and Physiology of the Eye

Internal Anatomy: Iris• Colored area in front of the

lens

Pupil• Clear opening in iris that

allows light to enter eye• Size controlled by two sets of

muscles in iris• Constriction – smaller• Dilation – larger• Controls amount of light

Learning Target: Anatomy and Physiology of the Eye

Human Eye

ReferencesEye Dissection. (n.d.). Eye Dissection. Retrieved May 15, 2013, from http://science.jburroughs.org/resources/skeleton/eye/eyedissection.html

Learning Check: Anatomy and Physiology of the Eye

I Can…Compare and contrast the structures of a sheep’s eye to that of a human eye and describe the structure and function of the components of an eye.

I Will…• Dissect a preserved sheep’s eye;• Identify the external structures of the eye• Describe the function(s) of each structure

• Identify the internal structures of the eye• Describe the function(s) of each structure

• Create a side view diagram of a human eye with appropriate labels

Video Learning Check: Sheep’s Eye Dissection

Name: ________________ Per. _____ Date: _______

List and describe two differences between a sheep’s eye and a human’s eye that were mentioned in the video (E.C. if you can name three).