3.1_ Vision and the Eye_ Essential Human Anatomy and Physiology II with Lab- Burtt.pdf

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2/15/20203.1: Vision and the Eye: Essential Human Anatomy and Physiology II with Lab- Burtt1/73.1: Vision and the EyeThe Special SensesThe five special senses vision, smell, taste, hearing, and equilibrium (balance) are the senses thathave specialized organs containing specialized receptor cells, which carry their impulses by way ofspecialized somatic and visceral afferents. The other sense, touch, is a somatic sense that does nothave a specialized sense organ. Instead, touch uses general receptors composed of modifieddendrites of sensory neurons. Touch includes pressure, vibration, pain, heat, and the combinedinformation is carried in general somatic afferents and general visceral afferents.Vision and the EyeThe organ responsible for sight is the eye, and it consists of three layers. The outer fibrous layerincludes the sclera and cornea. The posterior portion is known as thesclera(Figure 3.1), also11:03
2/15/20203.1: Vision and the Eye: Essential Human Anatomy and Physiology II with Lab- Burttknown as the “white of the eye. The anterior portion is known as thecornea(Figure 3.1). Thecornea is the transparent part of the eye where light enters.Aqueous humorfills the spacesbetween the cornea and the lens.Figure 3.1Lateral view of the cornea and sclera of the eye. (Both are highlighted in blue.)The middle layer of the eye includes choroid, the ciliary muscle, and the iris. The darkly-coloredposteriorchoroid(Figure 3.2) prevents light from dispersing throughout the eye. The choroid ishighly vascular and supplies blood to the other layers of the eye. The anteriorciliary body(Figure3.2) changes the shape of the lens, allowing it to focus. Theiris(Figure 3.2) is anterior to the ciliarybody and contains the circular colored portion of the eye. The iris controls the amount of light let intothepupil
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Term
Fall
Professor
Dr.Drouin
Tags
optic nerve, Essential Human Anatomy and Physiology

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