ZOOL 2403 Boros Exam 3 TTU Study Guide Questions and Answers Graded A

5 cranial senses - olfaction, taste, vision, hearing and equilibrium Olfactory pathway - odor-olfactory receptors-olfactory nerves-olfactory bulbs-olfactory tracts-olfactory cortex Gustatory Pathway - Taste buds are on the dorsal surface of the tongue taste-receptors- cranial nerves-medulla-gustatory cortex 6 primary taste sensations - sweet salty bitter sour umami water Cranial Nerves - Facial nerve(CN VII)- anterior 2/3s on tongue Glossopharyngeal (CN IX)- posterior 1/3 on tongue 3 Layers of the eyeball - Outer layer Middle Layer Inner Layer Outer Layer of the Eye - Dense connective tissue 1. The Sclera- White sheath protecting eyeball. 2. The Cornea- Transparent anterior continuation of the sclera that protects the lens. The cornea is avascular and can be transplanted. Middle Layer of the Eye - Loose connective tissue 1. Choroid- Contains blood vessels that supply oxygenated nutrients to the tissue of the eye. 2. Ciliary Body- Anterior continuation of the choroid, contains smooth muscle called ciliary muscles to control the shape of the lens for focusing on an object 3. Iris- Gives the eye color, it is composed of smooth muscle which change the size of the pupil to regulate the amount of light entering the eye. Inner Layer - Nervous tissue layer 1. Retina- contains photoreceptors associated with optic nerve(CN II) Rods and Cones are here Rods - Receptors activated by dim light Used for night vision Black and White vision Used for peripheral vision Cones - Receipts activated by bright light Used for daylight vision Color Vision Used for central vision Posterior Cavity - Transparent Gel(99% Water) Fills 80% of the eyeball Helps keep the retina in place Not produced until you are 4-5 Yrs old Only 1/2 full by the time you're 70 Yrs old It is not replaced. Visual Pathways - Light-Optic Receptors-Optic Nerves- Optic Chiasm-Thalamus-Visual Cortex Inferior Rectus - Eye looking down- Oculomotor nerve(III) Medial Rectus - Eye looking medially- Oculomotor nerve (III) Superior Rectus - Eyes looking Up- Oculomotor nerve (III) Lateral Rectus - Eye Looking laterally- abducens nerve (VI) Inferior Oblique - Eye rolls, looking up, and laterally out-oculomotor nerve(III)