WARM UP 4/29 1. Write the 12 cranial nerves in order 2. What does each do? a. Medulla a. Medulla b. Pons b. Pons c. Pituitary c. Pituitary d. Corpus collosum d. Corpus collosum 3. 4 ways to test the brain’s function.

NOTES Ch 11 4/29 The eye

EYE ANATOMY 3 layers: 1. Sclera 1. Sclera * outer layer * outer layer * white * white * protects and maintains shape * protects and maintains shape

2. CHLOROID * middle layer * middle layer * many blood vessels * many blood vessels 3. RETINA * inner layer * inner layer * where image is focused * where image is focused

CORNEA - Clear front of the eye PUPIL – circular dark opening of the eye * close or bright light – constricts * close or bright light – constricts * far or dim light – dilates * far or dim light – dilates

IRIS - colored part of the eye (muscle) - Due to the amount of melanin - low melanin = blue - low melanin = blue - high melanin = brown - high melanin = brown - no melanin = pink (albinism) - no melanin = pink (albinism) Muscles – sphincter and dilator papillae

LENS * Behind iris and pupil * Behind iris and pupil * elastic, disc-shaped, curved * elastic, disc-shaped, curved * ciliary body – muscle that holds or * ciliary body – muscle that holds or stretches lens stretches lens * bends light rays so you can focus * bends light rays so you can focus

VITREOUS HUMOR * clear jelly-like substance in the center of the eye * clear jelly-like substance in the center of the eye

RETINA * Layer in the eye where image is focused on * Layer in the eye where image is focused on Contains RODS and CONES RODS – sense black and whites CONES – sense colors

After image

BLIND SPOT * Where the optic nerve meets the eye on the retina there are no rods and cones so cannot see an image there * Where the optic nerve meets the eye on the retina there are no rods and cones so cannot see an image there BLIND SPOT TEST

CONJUCTIVA – thin membrane that lines eyelids and eye; secrete mucous for lubrication

LACRIMAL GLAND – secret tears and lubricating fluid into the eye - located in the upper and outer corner - located in the upper and outer corner LACRIMAL DUCT – tube that tear drain into. Empties into the nasal cavity.

LABELING THE EYE 1. Cornea 2. Iris 3. Pupil 4. Lens 5. Conjunctiva 6. Ciliary body 7. Vitreous humor 8. Retina 9. Blind spot 10. Optic nerve 11. Choriod 12. Sclera

EYE PHYSIOLOGY Image Enters eye through pupil cornealensRetina rods/ cones stimulated Message through optic nerve Interpreted at the occipital lobe

The eye forms a reversed image on the retina. Right at the beginning of your development as a baby, your brain learned to turn the reversed image right-side up and to interpret it. The eye forms a reversed image on the retina. Right at the beginning of your development as a baby, your brain learned to turn the reversed image right-side up and to interpret it.

Your brain adds to, removes from, reorganizes, and interprets the sensory clues it receives. And your senses can trick you. This is what we call an optical illusion. Your brain adds to, removes from, reorganizes, and interprets the sensory clues it receives. And your senses can trick you. This is what we call an optical illusion.

Look at the gray part. Which side (right or left) do you think is darker...?

Are the horizontal lines parallel, or do they slope?

How many legs does this elephant have?

Man playing a horn? Or woman's face?

A rabbit, looking right? Or a duck, looking left?

A skull? Or a woman looking into a vanity mirror?

A Native American profile? Or an Eskimo entering a cave?

One face? Or two profiles facing each other?

Young woman or old woman?

Which inner circle is bigger?

Up or down?

Which is your dominant eye? Point your finger at an object in the room far away. Try to line your finger up with it. Now close your left eye, then open it and close your right eye. What eye has the object lined up? That is your dominant eye

Test – Hole through your hand Roll a sheet of paper into a tube (longways) Hold it up to your right eye Hold your left hand in front of your left eye and move it out along the tube What happens?

Why 2 eyes? Each eye has a slightly different view, when put together things looks 3D – DEPTH PERCEPTION

LAB DEPTH PERCEPTION – ability to tell distances with the eyes