Brainscape's Knowledge GenomeTM

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


See full index

Ocular Anatomy > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

What bones make up the IOF? What is its function?

A

Maxilla, sphenoid, palatine

Separate the posterior portion of the lateral wall from the floor

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

What is found at the medial canthus?

A

Lacrimal fossa, lacrimal bone, palpebral fissures

Order of structures:

  • MPL (anterior)
  • Lacrimal Sac
  • MPL (posterior)
  • Horner’s muscle
  • Orbital septum
  • Check ligament of MR

-On lateral side, orbital septum first

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

Where is the meningeal foramen? What goes through it? Is it always present?

A

Greater wing of sphenoid, orbital branch of middle meningeal artery and accompanying vein, not always present

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

What bones make up the roof?

A

The frontal bone (anterior) and the lesser wing of the sphenoid (posterior) at the apex of the orbit

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

What are the functions of the septal system?

A
  1. Provides support or delicate neurovascular structures traversing the orbit
  2. Facilitates AND restricts the mov’t of extraocular muscles in coordinated fashion
  3. Compartmentalizes the orbit into various spaces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does the frontal sinus empty? What is the exception for where sinuses empty?

A 
Frontal sinuses are anterior superior to orbit, empty into middle meatus
Ethmoid sinuses (except posterior air cells) and maxillary sinuses also empty into the middle meatus
The sphenoid sinus empties into the superior meatus along with the posterior portion of the ethmoid sinuses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the SOF?What passes thru the SOF? What passes thru the SOF and Zinn?

A
  • Separates the greater wing from lesser wing
  • Ophthalmic div of V (lacrimal n and frontal n), trochlear n (IV), opthalmic v. And recurrent meningeal arteries run thru SOF
  • The oculomoter n, abducens (VI) and nasociliary (branch of ophthalmic div of V) run thru SOF and AOZ
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What bones make up the floor of the orbit?

A

Maxilla (central), zygomatic (anterior-lateral), palatine (posterior to maxilla)

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

What bones makes up the lateral wall of the orbit?

A

Zygomatic bone (anteriorly) and the greater wing of the sphenoid (posteriorly)

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

What bones make up the medial wall of the orbit?

A

Maxilla, Lacrimal bone, Ethmoid bone, Sphenoid

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

What blood vessels are found in the eyelid? Which would service the glands of Zeis? Where are the glands of Moll in relation to Zeis?

A

Two regions = peripheral arcade and the marginal arcade

Marginal arcade found near lid margin and would service the glands of zeis which are found at the lid margin (secrete sebum keeping eyelashes flexible), glands of Moll would also be serviced and are posterior to Zeis (they are apocrine sweat glands

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

What is found at the medial canthus?

A
  • Tear lake which separates the eyelids from eye

- plica semilunares and the caruncle

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

What is the sequence of layers in the eyelid?

A
  1. Skin/Cutaneous
  2. Subcutaneous areolar layer
  3. Striated muscle layer
  4. Submuscular areolar
  5. Fibrous layer
  6. Muscle of muller layer (smooth muscle)
  7. Conjunctiva
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the two venous drainage systems of the lid? Where is the separation? What motor innervations are coupled with these systems?

A
  • The superficial system (pre-tarsal system) and the deep system (post-tarsal system) are separated via the tarsal plate
  • Pre tarsal system with run with the sensory innervations (supraorbital n (V), Supra and infratrochlear n (IV), ophthalmic n (V), and the maxillary n (V)
  • Post tarsal system = motor innervations; orbicularis (CN VII/facial), levator (CNIII), Muller (sympathetic nerves)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the greyline? What is its significance?

A

Line of relatively avascular tissue found on lid, it is the surgical landmark for division of the eyelid into anterior (skin, subcutaneous areolar, orbicularis) and posterior (tarsal plate, smooth muscle, conjunctiva) portions

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

What causes depression of lower lid? What innervates?

A

The inferior muscle of muller and the lower rests muscle cause slight depression, sensory innervation = infraorbital n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the function of meibomian glands? What innervates them?

A

Secrete sebum forming lipid layer of the tear film, they are richly innervated by parasympathetic system with sympathetic sensory n (to a lesser extent)

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

What muscle closes the eye? What are the divisions of this muscle and what do they do?

A

Orbicularis oculi (inn by CNVII/facial)

  • Orbital: closes lid forcefully
  • Palpebral: closes lid gently (blinking)
  • Muscle of Riolan (holds lid close to globe)
  • Horner’s muscle: dilates lacrimal sac to assist entrance of tears into sac
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What muscles open the eye?

A

Levator palpebrae superioris (inn by CN III) with assistance from the superior muscle of muller (superior tarsal muscle) (inn by sympathetic n)

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

What is the main BV supply of the conjunctiva? It there a difference between the supply close to the cornea vs the periphery?

A
  • Mainly supplied via the tarsal arcades of the lids (peripheral arcade specifically)
  • near the corneal margin the anterior ciliary. Arterial system supplies the conjunctiva (episclerals become conjunctivals), these terminal arterioles become capillaries of the PCA
  • Near cornea=superficial marginal plexus which is all arteries and veins within few mm of corneal margin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the main differences between follicles and papillae?

A
  • Follicles are aggregates of lymphocytes and macrophages in the adenoid layer forming clear, fluid filled pockets w no BVs inside and are a much more specific clinical sign, presence tends to be more severe in infereior fornix vs superior when there is a response, no basophils/eosinophils in normal conjunc.epithelia
  • Papillae results from leakage of fluid/acute inflammatory cells from vascular core, there are areas of hypertrophy containing eosinophils/neutrophils, have BVs going thru them, more common in upper lid
22
Q

How many fornices in the eye? Which side does not have one?

A

Superior (largest), inferior (second largest, lateral (smallest) and medial is nonexistent bc plica semilunaris (no depth)

23
Q

What is special about the immunoactivity of the conjunctiva? What is it strongest?

A

Conjunctiva is the most immunoactive tissue in the eye, the palpebral region is most immunologically active specifically the lower palpebral conjunctiva (less BVs but more lymphoid tissue), upper palpebral conjunctiva has more BVs but less lymphoid tissue (to view this region eyelid must be double exerted)

24
Q

What are the layers of the conjunctiva?

A
  • Epithelium (goblet cells, palisades of Vogt)
  • Substantia Propia (separated into the superficial adenoid layer (fenestrated capillaries, lymph vessels) and the deep fibrous layer(large BVs, LVs, glands of Krause, arteriole w smooth muscle cells inn here, palpebral accessory lacrimal gland of wolfring here))
25
Q

What are the two lymph layers? Where do they drain?

A
  • Superficial plexus (forms pericorneal ring at corneal edge) and deep plexus
  • Medial areas - submandibular nodes
  • Lateral areas - preauricular nodes
26
Q

What gives the conjunctiva touch sensation? What is the innervation?

A
  • Inn by the infratrochlear (IV), lacrimal and supraorbital n (V) and infraorbital (V) and long/short ciliary n to circumcorneal region
  • end bulbs of Krause = round encapsulated nerve fiber endings that provide touch sensitivity (most numerous in limbal region) immediately under epithelium, naked endings = more common
  • the distribution to vasculature is dually innervated with sympathetic (superior cervical ganglion) and parasympathetic (pteryopalatine ganglion)
27
Q

What are the blood vessel injection patterns seen with 4 different causes?

A
  • Conjunctival: patterns increases when moving away from limbus
  • Mixed: corneal disorders mixed w intraocular irritations form red ring around the cornea and patterns increasing to periphery
  • Pericorneal: dialation of deeper vessels around cornea (lessens in periphery)
  • Ciliary: Redness around cornea coupled with more pronounced BV dilation near limbus
28
Q

What are the 4 forces involved in lacrimal drainage?

A
  • Gravity (4X more drain in inferior punctum vs superior)
  • Capillary action: most minor
  • Blinking: lateral component of tear excretions coupled w downward mov’t of lid pushes tears medially
  • As orbicularis oculi contracts, horner’s muscle puts pressure on ampulla driving tears into lacrimal sac
29
Q

What are the parts of the lacrimal drainage system?

A
  1. Lacrimal papillae (near punctum)
  2. Lacrimal punctum (superior and inferior on lid margin)
  3. Lacrimal canaliculi: superior and inferior tubes meeting and fusing into small tube at lacrimal sac
  4. Lacrimal sac sits in lacrimal fossa, MPL = only protection of lacrimal sac, bottom portion only covered by skin and orbicularis
  5. Nasolacrimal duct and bony nasolacrimal canal: begins at lower end of sac and leads to inferior meatus (bony canal provides protection)
  6. Nasal sinus near maxillary sinus, tumor in maxillary sinus can occlude the tunnel
30
Q

Where is the nasolacrimal duct protected, where isn’t it?

A

It is protected when it is in the bony nasolacrimal canal (lacrimal sac is not protected) and the inferior portion of the nasolacrimal duct is not surrounded by bone (mainly soft tissue)

31
Q

What is the basic unit of the lacrimal gland? What kind of cells are found here?

A

Composed of pie shaped serous and mucous cells acting via merocrine secretion leaded to a central lumen surrounded in microvilli acinus are surrounded by myoepithelial cells

32
Q

What are the different ducts of the lacrimal gland?

A
  • Intralobular ducts = narrowest lumina, 1-2 cell layer thick
  • Interlobular ducts =larger lumina, 2-4 cell layer thick
  • Main secretory= largest lumina, 3-4 cell layer thick
33
Q

How many secretory ducts in the lacrimal gland? What are the accessory palpebral lacrimal glands?

A

Approx 12 secretory ducts with the most being in the palpebral lobe (smaller lobe) that secrete watery tear film
-the accessory gland of Krause and Wolfring (Krause are smaller but more prevalent) secrete everyday tears for keeping eye moisturized

34
Q

What nerves innervate the lacrimal gland?

A
  • Lacrimal nerve carries afferent sensory fibers from the lacrimal gland
  • sympathetic n fibers from superior cervical ganglion (no effect on tear secretion)
  • Parasympathetic (efferent) fibers of CN VII (facial n) are solely responsible for secretion (high order=reflex tearing, crying, etc)
35
Q

What are the portions of the lacrimal gland?

A

Separated into orbital portion (superior and larger, 65-75%) an palpebral lobe (inferior and smaller, 25-35%)

36
Q

What is Descemet’s layer? Where are the cells generated?

A

It is the 4/5 layer of the cornea and is the basement membrane of the endothelium, cells are secreted by the endothelium over time causing a thickening of this layer with age

37
Q

What are gap junctions? Where are they present in the cornea?

A
  • Gap junctions form small channels (connexins) to allow for intercellular communication
  • Present in both the epithelium and the endothelium
  • Wing cells of epithelium linked via desmosomes and gap junctions
  • Stroma has Keratocytes that are joined via gap junctions
38
Q

How are Keratocytes arranged?

A

They make up the stroma of the cornea, fixes cells that are found between lamellae and cross each other at various angles while staying parallel to corneal surface, they have the greatest density anteriorly and are in a corkscrew pattern (scaffold, frame work), key in wound healing

39
Q

Where are basal cells located? What are their functions?

A

Located near the basement membrane of the epithelium
They are key in generating new cells (tissue damage)
One layer thick columnar cells w rounded heads, flat bases and nucleus near the apex
Are connected to BM via hemidesmosomes and w each other via desmosomes
Preform mitosis and migrate to surface (7 day trip)

40
Q

What are the nerve plexuses of the cornea and what are they innervated by?

A

Innervated by sensory (CNV) and sympathetic fibers

  • some travel radially into cornea to stroma forming stroma plexus (anterior-middle = nerve trunks and endings, nothing past that)
  • anteriorly to Bowman’s membrane forming subepithelial plexus
  • anteriorly to epithelium forming epithelial plexus
41
Q

What nerves are found specifically in the epithelium?

A

Naked nerve fibers with not myelination or Schwann cell (stromal plexus and subepithelial plexus have unmylinated but have Schwann cells surrounding)

42
Q

What is the diameter of the cornea?

A

11mm vert by 12 mm horizontally anteriorly and posteriorly it is circular (11.7mm each way)

43
Q

What is the lamellae of the stroma? How are they arranged?

A
  • Collagen in stroma organized into bundles called lamellae
  • Each lamellae are of uniform diameter 25-35nm and parallel to each other
  • Uniform size and separation = transparency of cornea
  • Anterior 1/3 are thinner but stronger than posterior 2/3
44
Q

What is the thickness of the stroma?

A

About 500 micrometers/90% of corneal thickness

45
Q

What are factors in corneal transparency?

A
  • water content 78%
  • Lamellae fibril arrangement (parallel with constant thickness and separation, separation distance must be less that half the wavelength of light (<200nm) for destructive interference of incoming light)
46
Q

What layers of the cornea do and don’t recover from injury?

A

All but Bowman’s layer and endothelium (polymegathism, cells spread out to cover space of lost/dead cells)

  • epithelium via basal cells
  • stroma via Keratocytes (new fibrils aren’t uniform diameter tho)
  • Descemet’s via endothelium
47
Q

Where are do the nerves enter the sclera?

A

Thru posterior penetrations, the lamina cribrosa (allows entrance of optic nerve and axons of ganglion cells

48
Q

What is the thickness of the sclera?

A

Stroma is the second layer and is the thickest

The sclera is thickest at the posterior pole and decreases at the equator then thickens towards the limbus

49
Q

What penetrations are found in the sclera?

A

Anterior: anterior ciliary arteries and veins (7 each), communications w canal of Schliemann (drain eye)
Middle: 4 vortex veins exit that drain uvea
Posterior penetrations: 2 long ciliary n, 2 long posterior ciliary arteries, optic nerve, short ciliary nerves and short posterior ciliary arteries (8-20)

50
Q

What is the relation of the sclera to tennon’s capsule?

A

Conjunctiva -> tenon’s capsule -> episclera

Tenon’s is outermost except at lamina cribrosa

Conjunctiva only associates w sclera anteriorly

51
Q

What is the size of the sclera?

A

Largest component of the fibrous tunic of the eye
Covers 5/6-9/10 of the globe
Diameter = 23-25 mm (wider horizontally than vertically)

Ocular Anatomy (3 decks)

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