Lens Anatomy and Physiology Flashcards

Flashcards for reviewing lecture notes on Lens Anatomy and Physiology.

This variable focussing ability is ___.

due to the crystalline lens ability to change shape and thus alter its power.

The lens is a .

Transparent, avascular, elliptical structure held behind the aperture of the pupil by the suspensory ligaments of the ciliary body.

The average adult equatorial dimension of the lens is approximately __.

~10 mm

The average adult axial thickness of the lens is approximately __.

~4 mm

The average power of the lens is approximately __.

~15 D

The anterior surface radius of curvature of the lens is approximately __.

~10 mm

The posterior surface radius of curvature of the lens is approximately __.

~6 mm

The lens anatomical landmarks include __.

Anterior and posterior poles, lens axis, equator

The major lens components include __.

Lens capsule, anterior epithelial layer, lens proper

The Lens Proper includes the __.

Cortex and Nucleus

The radius of curvature of the __ is ~10mm.

Anterior surface

The radius of curvature of the __ is ~6mm

Posterior surface

The lens capsule is an __.

elastic membrane

New lens fibres are formed by the __.

anterior epithelial layer

The outer layers of the lens proper are called the __.

cortex

The inner layers of the lens proper are called the __.

nucleus

The __ is an elastic bag that envelops the entire lens.

Lens capsule

The lens capsule is thickest near the __.

Equator

The lens capsule is thinnest at the __.

Posterior pole

The lens epithelium is a single layer of cuboidal cells found on the __.

Anterior surface only

The lens epithelium has subpopulations: __.

Central, germinative, transitional

The cells in the central zone of the lens epithelium have a __ appearance.

Squamous

The __ of the lens epithelium is where cell division occurs.

Germinative zone

Cells in the transitional zone differentiate into __.

Lens fibres

Lens fibres can extend up to __ in length.

10 mm

Lens fibres meet at the __ at the sutures.

Anteriorly and posteriorly

Division of lens fibers primarily occurs in the __.

Germinative zone

Elongation of lens fibers primarily occurs in the __.

Transitional zone

As fibre cells mature they lose __.

Organelles

Anterior epithelial cells proliferate in response to __ stimulation.

Fibroblast Growth Factor (FGF)

An aged lens has about __ lens fibres.

3.6 million

Lens fibres meet at the __ sutures.

Anterior and posterior

The foetal lens has a __ suture.

3-point

The Adult lens has a __ suture.

9-point

The lens itself lacks __.

Nerves, blood vessels, connective tissue

__ is a vital lens antioxidant.

Glutathione

Access to nutrients/waste disposal only via __.

Aqueous and vitreous

The majority of glucose metabolism in the lens is __.

Anaerobic

Lens morphogenesis begins with the thickening of surface __.

Ectoderm

The thickening of surface ectoderm invaginates to form the __.

Lens pit