Cornea Vol. 1 Flashcards Preview

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Flashcards in Cornea Vol. 1 Deck (32):
1

At what week of gestation does the eye begin to develop?

Week 4

2

From what embryologic germ layer does the optic vessel arise from?

Neuroectoderm

3

At what week of gestation does the optic cup form?

Week 5

4

What does the first wave of mesenchymal cells from the neural crest ectoderm become?

Corneal endothelium

5

What does the second wave of mesenchymal cells from the neural crest ectoderm become?

Corneal stroma and sclera

6

From what embryologic tissue layer does the corneal epithelium arise?

Surface ectoderm

7

At what month of gestation do the eyelids fuse?

Month 2

8

At what month of gestation does Bowman's layer and scleral spur form?

Month 4

9

At what month of gestation do the eyelids begin to open?

Month 5

10

At birth, how large is the globe in proportion to adult size?

80% of adult size

11

How thick are the eyelids at the eyelid margin?

0.5 mm

12

How thick are the eyelids at the oribital rim?

1.0 mm

13

How often are eyelashes normally replaced?

Every 3 to 5 months

14

How long does it take for eyelashes to regrow if trimmed?

2 weeks

15

How long does it takes to eyelashes to grow if epilated?

2 months

16

What type of glands are the glands of Moll?

Apocrine sweat glands

17

What type of glands are the glands of Zeis?

Sebaceous glands

18

What nerve provides sensory innervation to the eyelids?

Supraorbital nerve (CN V1)

19

What portion of the obicularis oculi is responsible for voluntary eyelid closure?

Orbital and preseptal

20

What portion of the obicularis oculi musce is responsible for subconscious blinking?

Pretarsal

21

What is the normal rate of blinking in the average person?

One blink per 3-4 seconds

22

In what direction do the eyelids move during a blink?

Medially and towards each other

23

What are the two major sources of blood supply to the eyelid?

Facial artery and ophthalmic artery

24

What are the two major venous sources of drainage of the eyelids?

Superior temporalveins to the jugular vein and ophthalmic vein to the cavernous sinus

25

What is the lymphatic drainage of the lateral eyelid?

Preauricular lymph node

26

What is the lymphatic drainage of the medial eyelid?

Submandibular and submental lymph nodes

27

How thick is the tarsus?

0.75 mm

28

How tall is the tarsus in1he upper eyelid? Lower eyelid?

Upper eyelid tarsus- 10 mm Lower eyelid tarsus -4 mm

29

What does the caruncle contain?

Hairs and sebaceous glands

30

What is the lies directly beneath and is adherent to the bulbar conjunctiva?

Tenon's capsule

31

What do the palisades of Vogt contain?

Limbal stem cells

32

What type of epithelium is found in the tarsal conjunctival? Fomix? Bulbar?

Tarsus- stratified cuboidal Fornix- stratified columnar Bulbar - stratified squamous