Podcast
Questions and Answers
What is the radius of curvature of the anterior surface of the cornea?
What is the radius of curvature of the anterior surface of the cornea?
- 7.8 mm (correct)
- 11mm
- 12mm
- 6.5mm
Which cells contribute to the formation of the corneal stroma and corneal endothelium?
Which cells contribute to the formation of the corneal stroma and corneal endothelium?
- Surface endoderm cells
- Neural ectoderm cells
- Surface ectoderm cells
- Neural crest cells (correct)
What is the refractive power of the cornea?
What is the refractive power of the cornea?
- 45D (correct)
- 40D
- 50D
- 60D
What is the central cornea thickness?
What is the central cornea thickness?
Which blood source does NOT supply blood to the cornea?
Which blood source does NOT supply blood to the cornea?
What type of cells make up the corneal epithelium?
What type of cells make up the corneal epithelium?
What type of cells join the basal layer of the epithelium to Bowman's membrane?
What type of cells join the basal layer of the epithelium to Bowman's membrane?
Which layer of the cornea contains Na/K ATP pumps to regulate water and ion flow?
Which layer of the cornea contains Na/K ATP pumps to regulate water and ion flow?
Which corneal layers CANNOT regenerate?
Which corneal layers CANNOT regenerate?
What is the average cell density of corneal endothelium in adults?
What is the average cell density of corneal endothelium in adults?
Which nerve innervates the cornea?
Which nerve innervates the cornea?
Where are corneal nerves located?
Where are corneal nerves located?
What is the circular structure at the termination of the Descemet’s membrane in the limbus called?
What is the circular structure at the termination of the Descemet’s membrane in the limbus called?
What types of cells make of the corneal endothelium?
What types of cells make of the corneal endothelium?
What forms a leaky barrier between the corneal stroma and the anterior chamber?
What forms a leaky barrier between the corneal stroma and the anterior chamber?
What is the approximate thickness of the corneal epithelium?
What is the approximate thickness of the corneal epithelium?
Which layer of the cornea is responsible for corneal epithelial renewal?
Which layer of the cornea is responsible for corneal epithelial renewal?
What is the composition of Bowman’s layer?
What is the composition of Bowman’s layer?
Which component of the corneal stroma contributes to its relatively high hydration?
Which component of the corneal stroma contributes to its relatively high hydration?
How are corneal endothelial cells linked together by?
How are corneal endothelial cells linked together by?
What passes through Bowman’s layer in the cornea?
What passes through Bowman’s layer in the cornea?
What is the approximate size of the cornea?
What is the approximate size of the cornea?
What is the turnover time of corneal epithelial renewal?
What is the turnover time of corneal epithelial renewal?
Which layer of the cornea is constantly produced and thickens throughout life?
Which layer of the cornea is constantly produced and thickens throughout life?
What is the composition of the corneal stroma?
What is the composition of the corneal stroma?
Of the total refractive power between 60-65, what amount is attributable to the cornea?
Of the total refractive power between 60-65, what amount is attributable to the cornea?
Which layer of the corneal epithelium contains gap junctions?
Which layer of the corneal epithelium contains gap junctions?
Which answer is correct regarding the corneal epithelium developement?
Which answer is correct regarding the corneal epithelium developement?
As we age, the cell density of our corneal endothelium cells increases over time.
As we age, the cell density of our corneal endothelium cells increases over time.
There are corneal nerves found in the Descemet's layer and endothelium.
There are corneal nerves found in the Descemet's layer and endothelium.
When the corneal nerves pass through Bowman's clayer, they become un-myelinated.
When the corneal nerves pass through Bowman's clayer, they become un-myelinated.
What is the primary contributor of glucose to all corneal layers?
What is the primary contributor of glucose to all corneal layers?
Which layers of the cornea is highly lipophilic?
Which layers of the cornea is highly lipophilic?
What is the principal provider of energy to epithelial cells?
What is the principal provider of energy to epithelial cells?
Corneal epithelial cells have the ability to alter corneal thickness by moving which ion into the tears?
Corneal epithelial cells have the ability to alter corneal thickness by moving which ion into the tears?
What does glucose convert to by glycolysis?
What does glucose convert to by glycolysis?
What can lactic acid not pass through?
What can lactic acid not pass through?
What is the effect of corneal stress on lactic acid accumulation?
What is the effect of corneal stress on lactic acid accumulation?
What happens to oxygen levels during sleep?
What happens to oxygen levels during sleep?
What drives the movement of K+ and Cl- into the corneal epithelium?
What drives the movement of K+ and Cl- into the corneal epithelium?
What is the primary driving force for water movement out of the corneal endothelium?
What is the primary driving force for water movement out of the corneal endothelium?
What happens to the partial pressure of O2 in the tears when the eye is closed?
What happens to the partial pressure of O2 in the tears when the eye is closed?
Where does the cornea primarily receives oxygen from where?
Where does the cornea primarily receives oxygen from where?
What cells contribute to corneal regeneration and are derived from limbal stem cells?
What cells contribute to corneal regeneration and are derived from limbal stem cells?
What is the primary driving force for water movement between the corneal endothelium and anterior chamber?
What is the primary driving force for water movement between the corneal endothelium and anterior chamber?
What is the primary function of the K+ channel in response to corneal changes in pH?
What is the primary function of the K+ channel in response to corneal changes in pH?
What is the primary factor contributing to the dehydration of the cornea?
What is the primary factor contributing to the dehydration of the cornea?
What is the first response of injury to epithelium?
What is the first response of injury to epithelium?
Which condition is characterized by small hyaline excrescences on the posterior surface of Descemet’s membrane at the periphery of the cornea?
Which condition is characterized by small hyaline excrescences on the posterior surface of Descemet’s membrane at the periphery of the cornea?
What corneal dystrophy is associated with the poor attachment between the epithelium and its basement membrane?
What corneal dystrophy is associated with the poor attachment between the epithelium and its basement membrane?
What is the characteristic feature of keratoconus?
What is the characteristic feature of keratoconus?
What is the primary cause of corneal edema resulting in impaired visual acuity?
What is the primary cause of corneal edema resulting in impaired visual acuity?
What is the characteristic feature of corneal guttata?
What is the characteristic feature of corneal guttata?
Which layer of the cornea can replace itself if damaged, leading to scar formation?
Which layer of the cornea can replace itself if damaged, leading to scar formation?
Which condition is characterized by the projection of the affected area outward in a cone shape due to the force exerted on weakened areas by intraocular pressure?
Which condition is characterized by the projection of the affected area outward in a cone shape due to the force exerted on weakened areas by intraocular pressure?
The limbal stem cells of the cornea are found in the Palisades of Vogt.
The limbal stem cells of the cornea are found in the Palisades of Vogt.
You are only able to see Descemet's membrane when there is corneal swelling.
You are only able to see Descemet's membrane when there is corneal swelling.
Herpes simplex virus is always bilateral.
Herpes simplex virus is always bilateral.
What is the approximate thickness of the thinnest area of the sclera where EOM rectal muscles insertion occurs?
What is the approximate thickness of the thinnest area of the sclera where EOM rectal muscles insertion occurs?
Which type of collagen fibers makes up the majority of the composition of the scleral stroma?
Which type of collagen fibers makes up the majority of the composition of the scleral stroma?
What is the primary function of the episclera in relation to the sclera?
What is the primary function of the episclera in relation to the sclera?
What is the primary contributor to the dehydration of the sclera?
What is the primary contributor to the dehydration of the sclera?
Which condition is characterized by a potentially destructive inflammatory process involving the scleral collagen or vasculitis?
Which condition is characterized by a potentially destructive inflammatory process involving the scleral collagen or vasculitis?
What is the primary cause of scleral ectasia?
What is the primary cause of scleral ectasia?
What is the primary blood supply for nourishment of the sclera?
What is the primary blood supply for nourishment of the sclera?
What part of the sclera attaches to the Tenon's capsule?
What part of the sclera attaches to the Tenon's capsule?
What is the primary cause of scleral thinning in scleritis?
What is the primary cause of scleral thinning in scleritis?
What is the primary innervation of the posterior sclera?
What is the primary innervation of the posterior sclera?
What is the characteristic feature of scleral foraminas?
What is the characteristic feature of scleral foraminas?
What is the posterior scleral spur an origin for?
What is the posterior scleral spur an origin for?
What is the primary component of the scleral stroma?
What is the primary component of the scleral stroma?
What is the primary orientation pattern of the collagen bundles in the scleral stroma in relation to the extraocular muscle tendinous insertions?
What is the primary orientation pattern of the collagen bundles in the scleral stroma in relation to the extraocular muscle tendinous insertions?
The stromal ground surface is similar to the cornea but has more fibroblasts and GAGs.
The stromal ground surface is similar to the cornea but has more fibroblasts and GAGs.
Branches of the short ciliary nerves innervate the medial and anterior sclera.
Branches of the short ciliary nerves innervate the medial and anterior sclera.
Medial and anterior sclera are innervated by long ciliary nerves.
Medial and anterior sclera are innervated by long ciliary nerves.
What disease is associated with the progression of myopia that thins the sclera?
What disease is associated with the progression of myopia that thins the sclera?
Which layer of the cornea can store O2?
Which layer of the cornea can store O2?
Flashcards
Radius of anterior corneal curvature
Radius of anterior corneal curvature
7.8 mm
Corneal stroma & endothelium cells
Corneal stroma & endothelium cells
Neural crest cells
Corneal refractive power
Corneal refractive power
45 Diopters (D)
Central cornea thickness
Central cornea thickness
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Blood supply to cornea (NOT)
Blood supply to cornea (NOT)
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Corneal epithelium cells
Corneal epithelium cells
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Epithelium-Bowman's membrane link
Epithelium-Bowman's membrane link
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Corneal water/ion regulation layer
Corneal water/ion regulation layer
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Irreplaceable corneal layers
Irreplaceable corneal layers
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Adult corneal endothelium density
Adult corneal endothelium density
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Corneal nerve
Corneal nerve
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Corneal nerve location
Corneal nerve location
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Descemet's Membrane Termination
Descemet's Membrane Termination
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Corneal endothelium cells
Corneal endothelium cells
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Leaky barrier between stroma and anterior chamber
Leaky barrier between stroma and anterior chamber
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Epithelium thickness
Epithelium thickness
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Corneal epithelial renewal layer
Corneal epithelial renewal layer
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Bowman's layer composition
Bowman's layer composition
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Corneal stroma hydration contributor
Corneal stroma hydration contributor
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Corneal endothelium cell connection
Corneal endothelium cell connection
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Bowman's layer passage
Bowman's layer passage
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Corneal Size
Corneal Size
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Epithelial Renewal Rate
Epithelial Renewal Rate
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Study Notes
Corneal Histological Features
- The cornea is approximately 71mm in size and is the principal refracting component of the eye.
- It is transparent and avascular, providing optimal light transmittance.
- The corneal layers include the epithelium, Bowman’s layer, stroma, Descemet’s membrane, and endothelium.
- The corneal epithelium is a stratified squamous nonkeratinized epithelium, approximately 50 μm thick and consists of surface, wing, and basal layers.
- The basal layer contains stem cells responsible for corneal epithelial renewal, with a turnover time of approximately 7 days.
- Bowman’s layer is an acellular dense layer composed of random collagen fibrils, approximately 8-14 μm thick and is prenatally produced.
- The corneal stroma, also known as Substantia Propria, is approximately 500 μm thick and composed of collagen fibers, keratocytes, and extracellular ground substance.
- Collagen fibers in the stroma form parallel layers called lamellae, contributing to corneal transparency.
- Ground substance in the stroma contains proteoglycans and contributes to the relatively high stromal hydration.
- Descemet’s membrane is the true basement membrane of the endothelium, constantly produced, and thickens throughout life.
- It consists of two laminae, with the anterior lamina being 3μm thick and exhibiting a banded appearance.
- Corneal nerves pass through Bowman’s layer, losing their Schwann cell covering, and the endothelium's Descemet’s membrane thickens throughout life.
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