Special Senses: the visual system Flashcards
• Lacrimal apparatus
o Lacrimal gland, lacrimal canaliculi, lacrimal sac, and nasolacrimal duct
• Lacrimal glands
o Situated superior to the lateral aspect of the eye
o Release a dilute salt solution (tears)
• Lacrimal puncta
o an opening through which fluid enters each lacrimal canaliculum.
• Lacrimal canaliculi
o form the first part of the nasolacrimal drainage apparatus that drains tears produced by the lacrimal gland.
• Nasolacrimal duct
o carries tears from the lacrimal sac into the nasal cavity.
• Lysozyme
o Antibacterial enzyme
o Contained in lacrimal secretion
• Eyelids/palpebrae
o Protect the anterior surface of each eye
• medial commissure (canthus)/lateral commissure (canthus)
o form the lateral and medial corners of the eyes.
• lateral caruncle
o fleshy raised area at the medial commissure
o produces whitish oily secretion
• conjunctiva
o mucous membrane
o lines the internal surface of the eyelids and continues over the anterior surface of the eyeball to its junction with the corneal epithelium
• ciliary glands
o modified sweat glands
o lie between the eyelash hair follicles and help lubricate the eyeball
• tarsal glands
o are a special kind of sebaceous gland at the rim of the eyelids inside the tarsal plate
• extrinsic eye muscles
o attached to the exterior surface of each eyeball
o control eye movement and make it possible for the eye to follow a moving object
o lateral rectus, medial rectus, superior rectus, inferior rectus, inferior oblique, superior oblique
• fibrous layer
o protective layer composed of dense avascular connective tissue
• cornea
o where light enters the eye
• vascular layer
o called uvea
o middle layer of internal eye
• choroid
o blood rich nutritive region containing a dark pigment that prevents light scattering within the eye
• ciliary muscles
o smooth muscles important in controlling lens shaoe and ciliary processes
• pupil
o a rounded open which lets light pass
• intrinsic muscles of the eye
o spincter pupillae of iris
o dilator pupillae of iris
o ciliary muscles
• retina
o innermost sensory layer of the eye
o three layer: photoreceptors, bipolar cells, and ganglion cells
• pigmented layer
o abuts the choroid and extends anteriorly to cover the ciliary body and the posterior side of the iris
• neural layer
o extends anteriorly only to the ciliary body
o contains the photoreceptors (cones and rods)
• optic disc/blind spot
o where the optic nerve leaves the eyeball
o located in a weak spot in the fundus(posterior wall)
