Chapter 8 study guide A&P

CH 8 STUDY GUIDE DEFINITIONS What are the four traditional senses ( smell, taste, sight, and hearing) called? special senses Term for Either large complex sensory organs or localized clusters of receptors special sense receptors Includes the extrinsic eye muscles , eyelids, conjunctiva, and lacrimal apparatus accessory structures Skin that protects the eyes and meet at the medial and lateral corners of the eye canthus The space between the medial and lateral corners of the eye plpebral fissure Hairs projecting from the border of each eyelid eyelashes Modified sebaceous glands associated with the eyelid edges tarsal glands Membrane that lines the eyelids and covers part of the surface of the eyeball conjunctiva Consists of the lacrimal gland and a number of ducts that drain the lacrimal secretions into the nasal cavity lacrimal apparatus Located above the lateral end of each eye lacrimal glands Where tears flush across the eyeball into lacrimal canaliculi Where the tears flush into after the Lacrimal Canaliculi lacrimal sac What empties into the nasal cavity nasolacrimal duct The enzyme that destroys bacteria and protects the eye surface as it moistens it lysozyme Muscles that are attached to the outer surface of each eye and produce movements that make it possible to follow a moving object external eye muscles A hollow sphere , the eye itself eyeball The outermost layer fibrous layer thick, glistening white connective tissue "white of the eye" that makes up the fibrous layer sclera Crystal clear "window" , which light enters the eye that makes up the fibrous layer cornea The middle layer of the eyeball, has three distinguishable regions vascular layer Most posterior, a blood-rich nutritive tunic that contains a dark pigment choroid What's the lens is attached to the ciliary zonule by ciliary body A suspensory ligament ciliary zonule The pigmented second smooth muscle structure iris A rounded opening , through which light passes pupil The innermost layer that is the delicate two-layered sensory layer Extends anteriorly only to the ciliary body retina This layer is composed of pigmented cells that, like those of the choroid, absorb light and prevent light from scatering inside the eye pigmented layer Contains millions of receptor cells neutral layer Cells that are called Photorecetors because they respond to light rods and cons Two-neutron chain that electrical signals pass from the photoreceptors through bipolar cells and then ganglion cells DEFINITIONS Electrical signals pass here before leaving the retina rods and cons Composed of ganglion cell axons , leaves the eye ball optic disc The site where the the optic nerve leaves the eye ball ganglion cells Anything that interferes with rod fuction hinders our ability to see at night night blindness A tiny pit that contains only cones fovea centralis The point of sharpest vision , and anything we wish to view critically is focused on the fovea centrails visual acuity Happens due to lack of all three cone types color blindness Result of the lens being perfectly transparent ans having the consistency of hardened jelly cataracts Anterior to the lens, contains a clear watery fluid aqueous humor Posterior to the lens, filled with a gel-like substance vitreous humor or body Located at the junction of the sclera and cornea scleral venous sinus or canal of Schlemm Compress the delicate retina and optic nerve glaucoma Posterior wall of the eye to be viewed and examined fundus The bending of the rays after speed changes refracted Ability of eye to focus specifically for close objects accommodation Where the fibers from the medial side of each eye cross over to the opposite side of the brain optic chiasma What results from the fiber tracts optic tracts The optic tract fibers synapse with neutrons in the thalamus optic radiation The loss of the same side of the visual field of both eyes hemianopia The reflexive movement of the eyes medially when we view close objects convergence