Sponge: Set up Cornell Notes on pg. 67 Topic: 12 Sponge: Set up Cornell Notes on pg. 67 Topic: 12.7: Structure of the Eye Essential Question: How does the shape of the lens change during accommodation? 12.7: Structure of the Eye 2.1 Atoms, Ions, and Molecules How does the shape of the lens change during accommodation? Turn in Lab 33 to printer

REVIEW: Special Senses Location of special senses? Sensory receptors are within large, complex sensory organs in the head Sight in eyes----->Rods and cones

Pg. 66 7m44s Human Body: Pushing the Limits: Sight 15 bullets

Structure of the Eye

Structure of the Eye Pg. 67 Structure of the Eye: Hollow Spherical (2.5 cm diameter) Wall has 3 layers Outer fibrous tunic Middle vascular tunic Inner nervous tunic

Structure of the Eye Directions: You will need 12 colors As we go through each part of the notes, please color-code, label AND describe the “diagram of the eye” Label small Leave room to write notes Continue on back if you run out of room

Layers of the Eye

Cornea

Outer Tunic Cornea aka “Window of the eye” Anterior 1/6 of outer eye Transparent No blood vessels Focuses incoming light rays Well supplied with nerves Many pain receptors Cornea

Extrinsic Eye Muscles Sclera

Outer Tunic Sclera Posterior 5/6 of outer eye White portion of eye Protects the eye Attachment for extrinsic muscles Optic nerve pierces the sclera in the back

Choroid Coat

Middle Tunic Choroid Coat Choroid coat Many blood vessels Provides blood supply Many melanocytes (pigments) that absorb extra light Keeps inside of eye dark Choroid Coat

+ suspensory ligaments Ciliary Body + suspensory ligaments

Middle Tunic Ciliary body Anterior portion of middle tunic Secretes aqueous humor Suspensory ligaments Hold lens in position and moves lens

Aqueous Humor (fluid)

Middle Tunic Aqueous humor (a-quee-us): fluid that circulates through the pupil and into the anterior chamber of the eye Provides nutrients Maintains the shape of the front of eye Removes waste If drainage is blocked—leads to glaucoma which can result in blindness

Lens

Middle Tunic Lens Lies behind iris and pupil Elastic Under constant tension Puts near/far objects into focus As we age, lens becomes larger and less elastic which leads to vision impairment

Accommodation P. 67 Accommodation: Changing of lens shape to view objects Suspensory ligaments Ciliary ligaments Close viewing: Relaxed Contracted Lens thick Far Viewing: Contracted Relaxed Lens thin

Pupil Iris

Middle Tunic Iris Colored portion of eye Lies between cornea and lens Smooth muscles that control the size of the pupils Pupils Controls light intensity Constricted: less light in Dilated: more light in

Retina Macula Lutea Fovea Centralis Optic Nerve (II) Optic Disc

Inner Tunic Retina Contains visual receptors (photoreceptors) rods/cones Continuous with optic nerve Macula lutea (mac-ula lu-tay-a) –spot in retina; absorbs extra light Fovea (fo-vea) centralis – center of macula lutea; region of retina that produces the sharpest vision; has largest concentration of cone cells Optic disc – Blind spot; contains no visual receptors Nerve fibers leave here and become part of the optic nerve

Posterior Cavity

Inner Tunic Posterior Cavity Largest compartment in eye Contains vitreous (vi-tree-us) humor – jelly-like substance that holds retina flat against choroid coat maintaining pressure Helps transmit light to retina

Aqueous Humor Extrinsic Eye Muscle Retina Macula Lutea Cornea Fovea Centralis Cornea Optic Nerve Posterior Cavity Pupil Optic Disc Choroid Coat Iris Sclera Lens Ciliary Body

Vision: Crash Course A+P 8m28s https://www.youtube.com/watch?v=o0DYP-u1rNM

Identifying Features/Other info Structure of the Eye Outer Tunic (pg. 470) 1. Cornea 2. Sclera Middle Tunic (pg. 470-474) 3. Choroid Coat 4. Ciliary Body 5. Lens & Accommodation 6. Aqueous Humor 7. Iris 8. Pupil Inner Tunic (pg. 474) 9. Retina & Optic Disc 10. Posterior Cavity Function Illustration Location Identifying Features/Other info

3-5 Bullets Each Video Notes: Split bottom pg. 66 into four sections Outer fibrous tunic Middle vascular tunic Inner nervous (sensory) tunic The Humors and the Lens 3-5 Bullets Each