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

Inner Layer of the Eyeball

Anatomy & Physiology

15. The Special Senses

Inner Layer of the Eyeball

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2:14 minutes

Problem 8

Textbook Question

Which sequence best describes a normal route for the flow of tears from the eyes into the nasal cavity?
a. Lacrimal canaliculi, lacrimal sacs, nasolacrimal ducts
b. Lacrimal ducts, lacrimal canaliculi, nasolacrimal ducts
c. Nasolacrimal ducts, lacrimal canaliculi, lacrimal sacs

Verified step by step guidance

Understand the anatomy of the lacrimal apparatus, which is responsible for tear production and drainage. Tears are produced by the lacrimal glands located in the upper outer region of each eye.

Learn the initial pathway of tears: After being secreted by the lacrimal glands, tears flow across the surface of the eye to keep it moist and clean.

Identify the next structure: Tears are collected by the lacrimal canaliculi, small channels located near the inner corner of the eye (medial canthus). These canaliculi transport tears to the lacrimal sac.

Understand the role of the lacrimal sac: The lacrimal sac is a reservoir located in the medial aspect of the orbit. It temporarily stores tears before they are drained further.

Trace the final pathway: From the lacrimal sac, tears flow into the nasolacrimal duct, which carries them into the nasal cavity. This explains why crying often leads to a runny nose.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Tear Production and Flow

Tears are produced by the lacrimal glands located above the outer corner of each eye. They flow across the surface of the eye to keep it moist and help remove debris. The normal route for tears involves their drainage through specific anatomical structures, which is essential for maintaining eye health and comfort.

Lacrimal Canaliculi

Lacrimal canaliculi are small ducts located at the inner corners of the eyelids. They collect tears from the eye's surface and direct them into the lacrimal sacs. Understanding the function of these canaliculi is crucial for comprehending how tears are drained from the eyes.

Nasolacrimal Duct

The nasolacrimal duct is a tube that carries tears from the lacrimal sac into the nasal cavity. This duct plays a vital role in the drainage system of tears, allowing excess moisture to be expelled into the nose, which is why crying can lead to a runny nose.

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Related Practice

Multiple Choice

Different animal species differ in the relative number of rods and cones that are present in their eyes. Which of the following statements would you expect to be true about these differences?

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