Questions and Answers
Which of these are accessory structures of the eye? (Select all that apply)
What is the frequency of reflexive eye-blinking?
Every 3-7 seconds
What protects the eye from airborne particles?
Eyelashes
Tarsal glands are embedded in connective tissue sheets called _____ plates.
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What is the thin mucous-secreting membrane lining the inner surface of the eyelids?
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What is the space formed between the eyelids and eyeball when the eyes are closed called?
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What is the function of lacrimal fluid?
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Which muscle rotates the eye downward?
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Which cranial nerve innervates the lateral rectus muscle?
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The major function of the conjunctival sac is to produce _____ which lubricates the eyeball.
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Study Notes
Accessory Structures of the Eye
- Accessory structures include the bony orbit, eyebrows, eyelids and eyelashes, conjunctiva, lacrimal apparatus, and extrinsic eye muscles.
Eyebrows
- Serve to shade the eyes and block perspiration and debris from entering.
Eye Blinking
- Reflexive eye-blinking occurs every 3-7 seconds.
Eyelashes
- Protect the eyes from airborne particles as part of the eyelid structure.
Tarsal Glands
- Embedded in connective tissue sheets known as tarsal plates.
- Modified sebaceous glands that secrete oil to lubricate the eyelid and prevent them from sticking together.
Conjunctiva
- A mucous-secreting membrane that lines the inner eyelids and covers the anterior surface of the eyeball.
Types of Conjunctiva
- Palpebral conjunctiva: Lines the inner eyelid.
- Bulbar conjunctiva: Covers the white part of the eye.
Conjunctival Sac
- A space between closed eyelids and the eyeball, facilitating lubrication.
Conjunctival Function
- Produces mucus to lubricate the eyeball and reduce eye infections.
Lacrimal Apparatus Components
- Includes lacrimal gland, lacrimal ducts, lacrimal puncta, lacrimal canaliculi, lacrimal sac, and nasolacrimal duct.
Lysozyme
- A bactericidal enzyme found within lacrimal fluid, protecting the eyes from infections.
Lacrimal Fluid Function
- Moistens the conjunctival sac and lubricates the eye, decreasing the risk of infections.
Extrinsic Eye Muscles
- Comprised of six muscles: superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, and inferior oblique.
Muscle Origination
- Rectus muscles originate from an annular ring, possibly including the superior oblique muscle.
Specific Muscle Functions
- Superior Rectus: Rotates the eye upward.
- Inferior Rectus: Rotates the eye downward.
- Medial Rectus: Rotates the eye toward the midline.
- Lateral Rectus: Rotates the eye away from the midline.
- Superior Oblique: Moves the eye downward and away from midline.
- Inferior Oblique: Moves the eye upward and away from midline.
Muscle Innervation
- Lateral rectus and superior oblique are not innervated by cranial nerve III (oculomotor).
- CN VI (Abducens): Innervates the lateral rectus muscle.
- CN IV (Trochlear): Innervates the superior oblique muscle.
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Description
Study the essential accessory structures of the eye with these flashcards. Learn about components like eyebrows, eyelids, and their functions in eye protection and health. Ideal for students in anatomy or physiology courses.
