Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Sensing and Seeing > External Eye and Adnexa Anatomy > Flashcards

External Eye and Adnexa Anatomy Flashcards

1
Q

What are the anatomical direction terms used in reference to the eye

A

Anterior, Posterior, Superior, Inferior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the placement of the bony orbit in the skull differ in carnivores vs herbivores and what is the effect of this on vision?

A

Carnivores: more rostrally
= more binocular, less peripheral vision, larger blind spot caudally

Herbivores: more laterally
= more peripheral, less binocular, small blind spot caudally but have small blind spot cranially as well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which species have an incomplete orbit
What structure is present to “complete” the orbit

A

Carnivores and pigs
Have orbital ligament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

the Pterygoapalatine fossa houses what anatomical structures?

A

Globe and adnexa
Formaina for arteries, veins, and nerves serving the globe/adnexa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which cranial nerves supply the globe/adnexa

A

CN II (optic)
CNIII (oculomotor)
CN IV (trochlear)
CNV1 (ophthalmic)
CN VI (abducens)
(CNV2 [maxillary])

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

where is the supraorbital fossa and what anatomical structures are present there

A

Space dorsal and caudal to orbit

Houses: an extension of retrobulbar fat pad
coronoid process of mandible extends into this space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Clin sig of retrobulbar fat pad

A

EXTRA-prominent in horses
“blobs-in-and-out” when horses chew!

Last place in body for fat storage - shows starvation/cachexia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

List the layers of the eyelid

A

Skin
Musculofibrous layer
Conjunctiva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What structures are in the skin layer of the eyelid

A

Cilia (eyelashes)
Sebaceous glands of cilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cilia species differences

A

Dogs - no lower eyelashes
Cats - no eyelashes at al! only fine hairs
Horses, Cows - prominent upper eyelashes, and also have lower eyelashes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What 3 structures are in the musculofibrous layer of the eyelid

A

Orbicularis oculi m
Orbital septum
Tarsus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the orbicularis oculi m, what does it do, and what is it innervated by?

A

Circumferential muscle - “purse-string”
Closes the eyelids
Innervated by CN 7, facial n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the orbital septum, where is it located, and what does it do?

A

Fibrous connective tissue
Arises from oribtal margin
Continuation of periorbita

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the tarsus and what does it do?

A

aka tarsal plate
Thickened extension of orbital septum

Gives structure to lid margin - near the free edge of the lids that supports the free edge, prevents “flopping”

Has ligamentous attachments to the orbit medially and laterally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the palpebral ligaments and what do they do

A

ligaments anchoring the eyelids medially &
laterally so that they close in a horizontal “line” rather than a “circle” when the orbicularis oculi contracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the levator palpebrae superioris m, what nerve innervates it and what does it do?

A
  • narrow strip of muscle running longitudinally into upper lid
  • contraction raises the upper lid
  • innervated by CN III, which also innervates the muscle that rotates the eye upward (dorsal rectus m.)
  • simultaneous contraction of the two muscles ensures that when the globe rotates upward, the upper lid is also raised
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

List the major muscles of the eyelid

A

Levatoir Palpebrae superiors
levator anguli oculi medialis
retractor anguli oculi lateralis
Superior tarsal m (aka Muller’s muscle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the muller’s muscle and what innervates it? What will result if it is damaged?

A

aka superior tarsal muscle
smooth muscle functions to maintain the elevation of the upper eyelid. It receives sympathetic innervation.

Damage to this muscle, or the nerves which supply it, will result in ptosis of the affected eye as seen in Horner syndrome.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the conjunctival layer. What is it made from? What cell type can be found here and what do they do? Describe species differences and what happens if it becomes inflamed.

A

Non keratinized epithelial layer
Thin and transparent

Goblet cells → mucin in the tear film
Also houses MANY microvessels and provides nutrition to eyelids and periphery cornea

lateral bulbar parts may be pigmented in some individuals, esp. Pugs, Eq, Bo

When inflamed vessels can become visible (bloodshot eyes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the palpebral conjunctiva

A

Posterior surface of palpebrae
Anterior and posterior surfaces of the 3rd eyelid

the portion lining the eyelids
- the internal surface of the superior and inferior
palpebrae, AND outer surface of the third eyelid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the bulbar conjunctiva

A

Surface of anterior sclera
the portion covering the sclera (“white part of the eye”) and inner surface of the third eyelid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the conjunctival fornix

A

Reflection of conjunctiva from eyelid to eyeball

the “pocket” at the deepest point of the superior and inferior palpebrae where the palpebral conjunctiva reflects onto the globe to become the bulbar conjunctiva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the conjunctival sac

A

Space between palpebral conjunctiva and bulbar conjunctiva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the fibrous portion fo the musculofibrous layer

A

Orbital Septum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What structures are present in the tarsal plate and what do the do?

A

tarsal glands (aka melbomian glands)

a row of glands just deep to the upper and lower tarsal plates

open onto free margin of each lid by a series of tiny, just-grossly visible openings (row of teeny dots)

secrete one layer of the tear film (the oily layer)

26
Q

What is the third eyelid

A

aka nictitating membrane, semilunar fold

Fold of conjunctiva surrounding a T shaped cartilage Bar of ‘T’ forms free edge of 3rd eyelid Stem of ‘T’ directed caudally into orbit between lower lid and globe

27
Q

What glands and tissue are associated with the third eyelid, where are they located, and what species differences are there

A

“superficial” gland of the third eyelid
- present in all species
- lies at the base (deepest) part of the cartilage
- “stem of the “T”
- contributes to part of the tear film

associated glands of the third eyelid
deep (Harderian) gland of the third eyelid
- present in pigs and ruminants

Lymphoid tissue present on bulbar surface

28
Q

How does the third eyelid move and species differences

A

held in retraction by tonic contraction of the orbitalis (smooth) muscle

the contraction is under sympathetic control (lack of sympathetic tone produces Horner’s syndrome)

  • motion over the eye is passive
    when eye is retracted (or retropulsed) into the orbit, the third lid slides over globe

In cat: skeletal muscle in 3rd eyelid so has voluntary control

29
Q

What is cherry eye

A

prolapse of superficial gland of third eyelid

30
Q

What three things make up tear film and what structures produe each?

A

external lipid layer - tarsal glands

Intermediate aqueous layer - lacrimal glands

Internal mucous layer - goblet cells in conjunctiva

31
Q

Describe the tear pathway

A

Lacrimal gland proper -> Lacrimal ductules -> lacrimal lake (gland of thrid eyelid also releases tears here)-> superior puncta/inferior puncta -> lacrimal ducts -> lacrimal sac -> nasolacrimal duct -> nasal cavoty

32
Q

List the categories of gland in the eye and what anatomical structues are in eachj

A

Lacrimal glands
- Lacrimal gland proper
- Gland of the 3rd eyelid
- Deep gland of the 3rd eyelid

Sebaceous glands
- Tarsal glands
- Ciliary glands

Mucus glands
- Goblet cells in conjunctiva

33
Q

What glands are near the eyes in carnivores and clin sig

A

Zygomatic salivary gland - ventral to eyeball on floor of orbit

can get inflammed and rupture -> press on eyeball

34
Q

What are the three layers of the orbital fascia

A

Periorbita
Superficial layer
Deep layer

35
Q

What is the periorbita, what is it made of, where does it attach, what structures does it surround and what structures does it give rise to?

A

Conical sheath

Smooth muscles and connective tissue

Attaches around optic canal to orbital rim

Surrounds eye mm, vessels, nerves, lacrimal gland, fat

Gives rise rostrally to orbital septum and tarsi of eyelids

36
Q

What is the orbitalis m, what does it do and what is it innervated by?

A

One of 3 smooth mm in the periorbita

Muscle fibers oriented circumferentially

Innervated by sympathetic nervous system

Action is to constrict the periorbita to maintain eyeball position in orbit

37
Q

What is the superficial muscular fascia and what structures does it cover

A

loose connective tissue deep to periorbital that surrounds levator palpebrae superioris and lacrimal gland

38
Q

What is the deep muscular fascia and what structures does it cover

A

aka Bulbar fascia, sheath of the globe, Tenon’s capsule, vagina bulbi

deepest of all “investing” layers and separates posterior globe from adnexa within the periorbita

blends with limbus of globe

surrounds each extraocular muscle and optic nerve

39
Q

What is the episclea space and what is its purpose and clin sig

A

space between the globe and Tenon’s capsule allows the eyeball to rotate freely

Enucleation (sx removal of eyeball) is performed here with dissection of the globe away from the tenon’s capsule

40
Q

Describe the orbital fat, its purpose, and clin sig

A

Intra-periorbital, Extra-periorbital

Serves as a protective cushion
within which the eyeball moves
Helps position globe in orbit

The last of fat stores to be utilized to meet energy needs -sunken eyes are a sign of cachexia

41
Q

Which extra ocular muscles are innervated by CN3

A

Dorsal, ventral, and medial rectus
Ventral Oblique

42
Q

Which extra ocular muscles are innervated by CN6

A

Lateral rectus, rectractor bulbi

43
Q

Which extra ocular muscles are innervated by CN4

A

Dorsal oblique

44
Q

Describe the retractor bulbi muscle, what it surrounds, what it does, species differences, and what it is innervated by

A

One muscle with 4 slips

Surrounds CN II Optic n

Innervated by CN VI Abducens n

Retraction of globe leads to passive protrusion of 3rd eyelid

Not present in primates or birds

45
Q

Which extraocular muscles originate at the apex of the periorbita

A

All 4 Rectus mm
Dorsal oblique m
Retractor bulbi m
Levator palpebrae superioris m

46
Q

Which extraocular muscles originate at the medial orbital wall

A

Ventral oblique m

47
Q

Which extra ocular muscles insert anterior to the equator of the globe

A

All 4 Rectus mm
Both Oblique mm

48
Q

Which extra ocular muscles insert posterior to the equator of the globe

A

Retractor bulbi m

49
Q

Which extraocular muscles insert in the upper eyelid

A

Levtator palpebrae superioris

50
Q

Which is the action of the rectus extraocular muscles

A

rotate the globe in the direction of their name along the horizontal or vertical axis
(ie dorsal rectus rotates the globe dorsally)

51
Q

Which is the action of the oblique extraocular muscles

A

Rotate globe relaytive to longitudinal axis

The dorsal oblique m rotates the top of the globe medially (intorsion).

The ventral oblique m rotates the top of the globe laterally (extorsion).

52
Q

action of retractor bulbi

A

Pulls globe caudally

53
Q

Action of levator palpebrae superioris

A

lifts upper eyelid

54
Q

What nerves supply sensory to the eyelid

A

CN V Trigeminal- Ophthalmic branch CN V Trigeminal- Maxillary branch

55
Q

What nerves supply somatic motor to the extracular mm

A

CN III Oculomotor
CN IV Trochlear
CN VI Abducens

56
Q

What nerves supply motor to the eyelid mm

A

CN III Oculomotor
CN VII Facial

57
Q

What nerve supplues parasymp. to the lacrimal gland

A

CN VII Facial

58
Q

What is the main artery to the eye

A

External ophthalmic aa

59
Q

Describe the arterial supply to the eye

A

Common carotid a to
External carotid a to
Maxillary a to
External Ophthalmic a to
Ciliary aa (Anterior, posterior Long, short)

60
Q

Describe the venous drainage to the eye

A

Satellite veins

Scleral venous sinus and plexus
- Site of resorption of aqueous humor

Vorticose veins
- Non-satellite veins draining the choroid

Sensing and Seeing (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions