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Special Senses IUSM – 2016 Lab 20 – Special Senses IUSM – 2016 I. Introduction Special Senses II. Keywords III. Slides A. Eye 1. General structure 2. Lens 3. Layers a. Fibrous tunic i. Cornea ii. Sclera b. Vascular tunic i. Iris ii. Ciliary body iii. Choroid c. Neural tunic (Retina) 4. Optic Nerve B. Eyelid C. Ear 1. General structure 2. Parts a. External ear b. Inner ear IV. Summary Fig 23-1, Junqueira, 13th ed. Lab 20 – Special Senses IUSM – 2016 I. Introduction Keywords II. Keywords III. Slides Anterior chamber Nucleated fibers A. Eye Bowman’s membrane Optic disc 1. General structure Canal of Schlemm Optic nerve 2. Lens Choroid Outer plexiform layer 3. Layers Ciliary body Pigmented epithelium a. Fibrous tunic Ciliary processes Posterior chamber i. Cornea Cochlea Retina ii. Sclera Cochlear duct Rods b. Vascular tunic Cones Scala media i. Iris Conjunctiva Scala tympani Cornea Scala vestibuli ii. Ciliary body Descement’s membrane Scleral venous sinus iii. Choroid Dilator pupillae m. Sphincter pupillae m. c. Neural tunic (Retina) Fovea Spiral ganglion 4. Optic Nerve Hair cells Spiral organ of Corti B. Eyelid Inner limiting membrane Stria vascularis C. Ear Inner plexiform layer Substantia propria 1. General structure Iris Suspensory ligament 2. Parts Lens Tarsal plate a. External ear Limbus Tectorial membrane b. Inner ear Meibomian glands Vestibular membrane IV. Summary Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction Slide Overview II. Keywords III. Slides A. Eye 1. General structure 2. Lens anterior 3. Layers cavity a. Fibrous tunic i. Cornea lens optic nerve ii. Sclera posterior cavity (CN II) b. Vascular tunic cornea (vitreous chamber) i. Iris ii. Ciliary body iii. Choroid c. Neural tunic (Retina) iris 4. Optic Nerve w/ pupil B. Eyelid C. Ear 1. General structure 2. Parts a. External ear b. Inner ear neural tunic sclera IV. Summary vascular tunic fibrous tunic Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords III. Slides A. Eye 1. General structure 2. Lens 3. Layers a. Fibrous tunic i. Cornea ii. Sclera b. Vascular tunic lens i. Iris ii. Ciliary body posterior anterior iii. Choroid cavity c. Neural tunic (Retina) chamber (vitreous chamber) between cornea and iris 4. Optic Nerve anterior B. Eyelid posterior cavity chamber C. Ear between iris and lens 1. General structure 2. Parts a. External ear the eye is divided into two cavities based upon the lens: posterior to the lens is the posterior cavity containing b. Inner ear the vitreous body (humor) which is a large gelatinous mass of transparent connective tissue composed mainly IV. Summary of water; anterior to the lens is the anterior cavity which is subdivided into the anterior and posterior chambers based upon the iris; the anterior cavity is filled with aqueous humor which is produced by the ciliary processes in the posterior chamber and flows through the pupil into the anterior chamber Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords III. Slides A. Eye 1. General structure non-nucleated 2. Lens fibers (contain crystallin proteins) 3. Layers a. Fibrous tunic i. Cornea ii. Sclera differentiation b. Vascular tunic i. Iris ii. Ciliary body nucleated fibers iii. Choroid c. Neural tunic (Retina) subcapsular epithelium 4. Optic Nerve capsule B. Eyelid (basal lamina) C. Ear 1. General structure 2. Parts a. External ear the lens is an avascular, biconvex, transparent disc derived from epithelium and attached to the ciliary body by b. Inner ear the suspensory ligament; the flexibility of the lens allows it to change shape to affect light refraction upon the IV. Summary retina; its transparency is principally due to the loss of light-scattering organelles (such as the nucleus), the presence of crystallin proteins, and the precise shape and organized packing of its non-nucleated fibers Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords the fibrous tunic is the outermost layer III. Slides of the eye; it consists of two major regions: A. Eye th cornea 1. General structure 1. sclera - posterior 5/6 ; the “white” 2. Lens of the eye; consists of dense CT that 3. Layers protects the eye and serves as site for extraocular muscle attachment a. Fibrous tunic th i. Cornea 2. cornea - anterior 1/6 ; transparent ii. Sclera and avascular; serves as primary b. Vascular tunic site of light refraction; density of pain receptors is >100x greater than i. Iris in skin and >10x than in dental pulp ii. Ciliary body iii. Choroid c. Neural tunic (Retina) 4. Optic Nerve sclera B. Eyelid C. Ear 1. General structure the sclera and cornea are joined at the limbus (Lt. “edge”) 2. Parts which encircles the cornea and serves as its source of limbus a. External ear cornea stem cells; it becomes more stratified at the conjunctiva b. Inner ear which is the stratified columnar mucous membrane with IV. Summary numerous goblet cells that covers the exposed portion of the sclera (not the cornea) and the inside of the eyelid conjunctiva Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords III. Slides A. Eye 1. General structure 2. Lens 3. Layers a. Fibrous tunic i. Cornea ii. Sclera corneal corneal b. Vascular tunic epithelium endothelium lamellae of collagen bundles with i. Iris stratified interspersed keratocytes simple ii. Ciliary body squamous squamous iii. Choroid c. Neural tunic (Retina) 4. Optic Nerve B. Eyelid C. Ear 1. General structure 2. Parts a. External ear Bowman’s membrane Descemet’s membrane (des-suh-mays) b. Inner ear (anterior limiting membrane) (posterior limiting membrane) IV. Summary Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords III. Slides A. Eye 1. General structure 2. Lens 3. Layers a. Fibrous tunic i. Cornea ii. Sclera corneal b. Vascular tunic epithelium i. Iris ii. Ciliary body iii. Choroid c. Neural tunic (Retina) Bowman’s 4. Optic Nerve membrane B. Eyelid C. Ear 1. General structure 2. Parts a. External ear b. Inner ear the corneal epithelium is nonkeratinized stratified squamous epithelium generally with 5-7 cell layers; cell IV. Summary turnover is about 7 days from stem cells located in the limbus; unlike the overlying epithelium, Bowman’s membrane is relatively static and does not regenerate after injury; the uniform orientation of the CT fibers within the substantia propria contributes to corneal transparency Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords III. Slides A. Eye 1. General structure 2. Lens Descemet’s membrane 3. Layers (des-suh-mays) a. Fibrous tunic i. Cornea corneal endothelium ii. Sclera keratocyte b. Vascular tunic i. Iris ii. Ciliary body iii. Choroid c. Neural tunic (Retina) 4. Optic Nerve B. Eyelid C. Ear 1. General structure 2. Parts a. External ear the cornea is avascular, so most metabolic exchange occurs across the corneal endothelium with the aqueous b. Inner ear humor in the anterior chamber; additionally the endothelium keeps the cornea dehydrated by actively pumping Na+ into the chamber (water follows); Descemet’s membrane separates the endothelium from the substantia IV. Summary propria, but unlike Bowman’s membrane it is readily regenerated after injury if the endothelium is intact; unlike the corneal epithelium, the endothelium has limited regenerative potential Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords III. Slides retina A. Eye 1. General structure 2. Lens 3. Layers choroid a. Fibrous tunic i. Cornea ii. Sclera b. Vascular tunic i. Iris ii. Ciliary body sclera iii. Choroid c. Neural tunic (Retina) 4. Optic Nerve B. Eyelid C. Ear 1. General structure 2. Parts a. External ear th b. Inner ear the sclera (Gr. “hard”) is the opaque layer of dense CT constituting the posterior 5/6 of the fibrous tunic; it IV. Summary serves to maintain the rigidity of the eye and as the site of attachment for the tendons of the extraocular muscles Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords the vascular tunic (uvea) is the middle layer of the III. Slides eye; it consists of three parts: A. Eye 1. General structure 1. iris: most anterior portion of vascular tunic; contains many melanocytes that provide the ciliary choroid 2. Lens color of the eye and prevent the passage of body 3. Layers light, leaving only the central pupil (opening) a. Fibrous tunic for light to pass through; contains: iris i. Cornea a. dilator pupillae m. ii. Sclera b. Vascular tunic b. sphincter pupillae m. i. Iris p 2. ciliary body: expansion of the vascular tunic, ii. Ciliary body u encircling the lens; consists of: p iii. Choroid a. ciliary muscle i c. Neural tunic (Retina) l 4. Optic Nerve b. ciliary processes B. Eyelid 3. choroid: located in posterior 2/3rd of eye; C. Ear contains: 1. General structure a. loose CT 2. Parts b. lots of vasculature a. External ear b. Inner ear c. melanocytes IV. Summary Lab 20 – Special Senses IUSM – 2016 Slide 78: Eye, H&E I. Introduction II. Keywords III. Slides A. Eye 1. General structure 2. Lens 3. Layers stroma a. Fibrous tunic i. Cornea dilator pupillae m. ii. Sclera b. Vascular tunic i. Iris anterior ii. Ciliary body chamber iii. Choroid sphincter pupillae m. c. Neural tunic (Retina) 4. Optic Nerve pigmented epithelium B. Eyelid C. Ear 1. General structure 2. Parts a. External ear the iris consists of a CT stroma with an uncovered anterior surface, not lined by an epithelium bordering the anterior chamber; the posterior blocks light entering the eye except through the pupil b.
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