Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

15. The Special Senses

The Lens and Focusing Light on the Retina

Anatomy & Physiology

15. The Special Senses

The Lens and Focusing Light on the Retina

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Multiple Choice

Which structure in the eye is primarily responsible for refining the focus of an image onto the retina?

Cornea

Sclera

Iris

Lens

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Verified step by step guidance

Step 1: Begin by understanding the anatomy of the eye and the role of each structure mentioned in the problem. The cornea is the transparent front part of the eye that helps to refract light but does not refine focus. The sclera is the white outer layer of the eye that provides structural support and protection, not involved in focusing light.

Step 2: Next, consider the iris. The iris is the colored part of the eye that controls the size of the pupil, regulating the amount of light entering the eye, but it does not focus light onto the retina.

Step 3: Now, focus on the lens. The lens is a transparent, flexible structure located behind the iris. Its primary function is to refine the focus of light onto the retina by changing its shape through the process of accommodation.

Step 4: Understand the process of accommodation. The ciliary muscles adjust the shape of the lens to focus on objects at varying distances. This ensures that the image is sharply focused on the retina, where photoreceptor cells convert light into neural signals.

Step 5: Conclude that the lens is the structure primarily responsible for refining the focus of an image onto the retina, as it plays a direct role in adjusting focus for clear vision.