Lecture Human anatomy and physiology - Chapter 15: The special senses (part a)

Chapter 15 (part a) provides knowledge of the eye and vision. In this chapter, you will learn to: Describe the structure and function of accessory eye structures, eye layers, the lens, and humors of the eye; outline the causes and consequences of cataracts and glaucoma; trace the pathway of light through the eye to the retina, and explain how light is focused for distant and close vision; outline the causes and consequences of astigmatism, myopia, hyperopia, and presbyopia.
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Lecture Human anatomy and physiology - Chapter 15: The special senses (part a) PowerPoint® Lecture Slides prepared by Janice Meeking, Mount Royal College CHAPTER 15 The Special Senses: Part ACopyright © 2010 Pearson Education, Inc. The Eye and Vision • 70% of all sensory receptors are in the eye • Nearly half of the cerebral cortex is involved in processing visual information! • Most of the eye is protected by a cushion of fat and the bony orbitCopyright © 2010 Pearson Education, Inc. Accessory Structures of the Eye • Protect the eye and aid eye function • Eyebrows • Eyelids (palpebrae) • Conjunctiva • Lacrimal apparatus • Extrinsic eye musclesCopyright © 2010 Pearson Education, Inc. Eyebrow Eyelid Eyelashes Site where conjunctiva merges with cornea Palpebral fissure Lateral commissure Iris Eyelid Pupil Sclera Lacrimal Medial (covered by caruncle commissure conjunctiva) (a) Surface anatomy of the right eyeCopyright © 2010 Pearson Education, Inc. Figure 15.1a Eyebrows • Overlie the supraorbital margins • Function in • Shading the eye • Preventing perspiration from reaching the eyeCopyright © 2010 Pearson Education, Inc. Eyelids • Protect the eye anteriorly • Palpebral fissure—separates eyelids • Lacrimal caruncle—elevation at medial commissure; contains oil and sweat glands • Tarsal plates—internal supporting connective tissue sheet • Levator palpebrae superioris—gives the upper eyelid mobilityCopyright © 2010 Pearson Education, Inc. Eyelids • Eyelashes • Nerve endings of follicles initiate reflex blinking • Lubricating glands associated with the eyelids • Tarsal (Meibomian) glands • Sebaceous glands associated with follicles • Ciliary glands between the hair folliclesCopyright © 2010 Pearson Education, Inc. Levator palpebrae superioris muscle Orbicularis oculi muscle Eyebrow Tarsal plate Palpebral conjunctiva Tarsal glands Cornea Palpebral fissure Eyelashes Bulbar conjunctiva Conjunctival sac Orbicularis oculi muscle (b) Lateral view; some structures shown in sagittal sectionCopyright © 2010 Pearson Education, Inc. Figure 15.1b Conjunctiva • Transparent membrane • Palpebral conjunctiva lines the eyelids • Bulbar conjunctiva covers the white of the eyes • Produces a lubricating mucous secretionCopyright © 2010 Pearson Education, Inc. Lacrimal Apparatus • Lacrimal gland and ducts that connect to nasal cavity • Lacrimal secretion (tears) • Dilute saline solution containing mucus, antibodies, and lysozyme • Blinking spreads the tears toward the medial commissure • Tears enter paired lacrimal canaliculi via the lacrimal puncta • Drain into the nasolacrimal ductCopyright © 2010 Pearson Education, Inc. Lacrimal sac Lacrimal gland Excretory ducts ...