Module 1 Lesson 2 - 9
Lesson 2 — Photoreception: The Eye
Self-Check
To ensure that you have mastered the concepts of this lesson, complete the following self-check questions.
Use the following information to answer the next question.
Visual Interpretation
The brain integrates visual information from both eyes. Some of the steps in the visual pathway are shown below.
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rods and/or cones change light energy into a nerve impulse
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nerve impulse travels to the temporal area of the brain for sorting
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nerve impulse travels to the occipital lobe of the cerebral cortex for interpretation
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nerve impulse leaves eye via the optic nerve
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light energy enters the eye and strikes the retina
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In the four spaces below, record in the correct order the number of the four steps that are part of the visual pathway.
____ ____ ____ ____
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Which of the following rows identifies the cornea in the diagram above and gives its functions?
Row Cornea Function
A. 1 Bend light toward the pupil
B. 1 Controls amount of light entering the eye
C. 2 Bends light toward the pupil
D. 2 Controls amount of light entering the eye
- Regulates the amount of light entering the eye
- Translates light stimuli into nerve impulses
- Bends light as it first passes into the eye
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Protects the eye and maintains its shape
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Match three of the functions listed above with the eye structures given below.
Use the following information to answer the next question.
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Function:
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_____ | _____ | _____ |
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Structure:
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Sclera | Cornea | Retina |
Self-Check Answers
- 5, 1, 4, 3
- A
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432
Lesson Summary
This lesson explored the following questions:
- What are the major structures of the eye?
- How do these structures function?
- How do they communicate with the nervous system to support the integrated act of seeing?
In this lesson, you continued to exp[lore the senses. Photoreception, or the sense of vision, involves the largest number of sensory receptors in the body. The eyes gather approximately 80% to 90% of the information about the external environment and transmit it to the brain.
Vision is kept in focus by the accommodation reflex. The light and dark adaptation adjust the amount of light entering the eye. Cones are activated to allow colours to be seen. The occipital lobes of the brain integrate and interpret this information.