Lab Report - Eye Disection

8/3/2019 Lab Report - Eye Disection

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Lab Report

EYE DISECTIONDate

By

Class

Teacher

Introduction:In this lab experience we performed an eye dissection in which we were able to identify almost every part of the eye,studying in a deeper manner its anatomy.

This was a very fulfilling experience for me in particular because I plan to study a medical career, most likely veterinary medicine.

Background Information:

1. Extra-ocular muscles: There are six: medial rectus (MR), lateral rectus (LR), superior rectus (SR), inferiorrectus (IR), superior oblique (SO), and inferior oblique (IO).

Músculos extra-oculares: Son seis. Recto interno o medio, recto externo o lateral, recto superior, recto inferior,

oblicuo superior o mayor y oblicuo inferior o menor.

2. Optic nerve: Nerve that carries electrical impulses from photoreceptor cells (rods and cones) in the retina to the

visual cortex in the brain.

N ervio óptico: conexión neural que trasmite información visual desde la retina al cerebro. El nervio óptico tiene 1.5

millones de axones, cuyos cuerpos celulares están en las células retinales ganglionares, localizadas en la capa

celular ganglionar de la retina interna del ojo 3. Sclera: "the white of the eye." It is the tough, opaque tissue that serves as the eye's protective outer coat.

Esclerótica: Es la capa que recubre el globo ocular, con excepción del frente. Es una membrana fibrosa, opaca y

resistente para protección del ojo (el blanco del ojo).

4. Cornea: One-sixth of the outer layer of the eye (called fibrous tunic) that bulges forward. The transparent dome

which serves as the outer window of the eye.C órnea: Prolongación de la esclerótica. Es un casquete de esfera transparente, mide aproximadamente 12,5 a 11,5

mm de diámetro, con un espesor central de 0,52 mm que periféricamente aumenta a 0,65 mm.

5. A queous humor: Clear fluid in the front of the eye, between the cornea and the iris (anterior chamber). H umor acuoso: líquido claro, llena la cámara frontal entre la córnea y el iris.

6. Lens: Nearly spherical body in the eye, located behind the iris.

C ristalino: Lente semirrígido de membranas claras situado detrás del iris. 7. Ciliary Body: Lies just behind the iris. A ttached to the ciliary body are tiny fibers called zonules. The lens is

suspended inside the eye by the zonular fibers.C uerpo ciliar: Desde la parte anterior de la retina (ora serrata) hasta la base del iris, detrás de la unión de la

esclerótica con la córnea. Se constituye por: Los procesos ciliares, pliegues en la parte anterior del cuerpo ciliar de

donde parten las fibras zonulares que lo unen al cristalino, y el músculo ciliar, banda circular de músculo liso.

8. Iris: Colored part of the eye surrounding the pupil. It lies between the cornea and the lens.

I ris: La parte anterior de la retina. Está perforado en su centro por el orificio pupilar.

9. Vitreous humor: clear gel which occupies the posterior compartment of the eye, located between the crystalline

lens and the retina and occupying about 80% of the volume of the eyeball.

H umor vítreo: Se encuentra posterior al cristalino, un gel transparente que le da volumen al globo ocular.

10. Choroid: between the retina and sclera. It is composed of layers of blood vessels.

C oroides: membrana delgada, aterciopelada, con células de pigmento negro que se encuentra en contacto con la

esclerótica.



11. Retina: multi-layered transparent sensory tissue that lines the back of the eye. Retina: Membrana transparente. Es la capa más interna de las tres membranas que constituyen el globo ocular. Se

extiende desde la ora serrata hasta la papila.

12. Macula: A lmost in the center of the retina, temporal to the optic nerve. It is a small and highly sensitive part of the retina.

Mácula: La mácula es la zona de la retina situada en el polo posterior, de mayor agudeza visual y que constituye la

región central del campo visual.

13. Conjunctiva: Mucous membrane that lines the visible part of the eye and the inner surface of the eyelids.C onjuntiva: mucosa transparente que cubre las superficies internas de los párpados.

Materials:

y Cow eye

y Scalpel

y Scissors

y Tweezers

y Dissecting tray

y

loves

y ¡

oggles

Procedure:

1. Place the cow eye on the dissecting tray. Carefully cut off the extra fat and the muscle using the tweezers and the

scissors.2. ¢

ently cut through the sclera around the middle of the eye so that one half will have the cornea, lens, iris, and

ciliary body, and the other half will contain the posterior features.

3. Cut the cornea from the eye along the edge where the cornea meets the sclera, careful not to cut the iris or thelens.

4. A fter examining both sides of the anterior half of the eye, cut around the lens, through the iris, and pull

the lens out.

5. Carefully place it on a paper with very small writing. Look through the lens.6. Use a pair of tweezers to gently lift the retina off the inside wall of the eye.

Observations:

1. First of all we were able to identify the extra-ocular muscles, the optic nerve, the sclera, and the cornea, simplyby observing the eye before beginning the actual dissection.

2. The eye had a covering of fat and muscle tissue all around. A s we got closer to the actual eyeball, we noticedsome muscles were attached directly to the sclera and along the optic nerve.

3. When we intended to cut through the sclera using the scalpel, it felt much resistant and strong than what we

expected. First, the membrane holding the aqueous humor broke, and the almost transparent liquid spilled.

Then the membranes holding the vitreous humor broke. Since the eye was a week old when we did theexperience, the vitreous was a rather black.

4. We noticed the cornea is also hard and strong, which explains how it protects the delicate parts inside the eye.

5. The iris was dark brown, almost black. We were able to distinguish the small fibers within it. It was well attachedto the lens.

6. We flipped the anterior half over and examined the back half, located the lens and ciliary body surrounding it.

7. A fter examining both sides, we took the lens out. It has quite hard. We placed it on a piece of paper with writingon it, and saw how it could magnify images.

8. We then identified the retina, the macula and the blind spot, the place where the optic nerve attaches to the eye.

We gently lifted the retina off the inside wall of the eye. It was very delicate, so we removed it bit by bit.9. Underneath the retina there was a very shiny and colorful tissue, the choroid coat.

Conclusions:

Practical activities definitely help us learn and understand better the anatomy of structures, because instead of just

learning it by repetition and picturing it in our minds, we have already seen it by ourselves, and we have the image

recorded in our minds. It also helps us understand the physiology of the organ, seeing the arrangement, shapes andphysical appearance of each tissue and structure that forms the whole organ.It was pretty amazing being able to feel how firm was the sclera and the iris. A lso the lens turned out to be much

tougher than what I expected.

The eye is a very complex organ despite its relatively small size. A s in any other organ, each part of the eye isnecessary for an optimum functioning.



Bibliography:

http://www.tedmontgomery.com/the_eye/index.html

http://www.hometrainingtools.com/eye-dissection-project/a/1379/

http://www.allaboutvision.com/resources/anatomy.htm

http://www.cuaad.udg.mx/~lprado/portal-psic/Sistema%20visual/ A natomia%20ojo.htm

http://sisbib.unmsm.edu.pe/bibvirtual/libros/medicina/cirugia/tomo_iv/anata_ocu.htm

http://www.oftalmologia.org/rco/index.php?option=com_content&view=article&id=18:anatomdel-nervio-

co&catid=21:glaucoma&Itemid=37

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Lab Report - Eye Disection