Embryo Flashcards
<p>Arrange the following structures in order of formation of the eye:</p>
<ul> <li>optic pits</li> <li>optic cups</li> <li>embryonic plate</li> <li>optic vesicles</li> <li>neural plate</li></ul>
<p>embryonic plate--> neural plate--> optic pits-->optic vesicles --> optic cups</p>
<p>What are the 3 layers that make up the Embryonic Plate?</p>
<ol> <li>Ectoderm</li> <li>Mesoderm</li> <li>Endoderm</li></ol>
<p>Which layer of the embryonic plate forms the eye and brain? </p>
<p>Ectoderm </p>
<p>What are the 3 layers that make up ectoderm?</p>
<ul> <li>Neural ectoderm</li> <li>Surface ectoderm</li> <li>Neural crest</li></ul>
<p>Whatis the blue layer on the figure?</p>
<p>Ectoderm</p>
<p>What is the yellow layer on the figure?</p>
<p>Mesoderm</p>
<p>What is the red layer on the figure?</p>
<p>Ectoderm</p>
<p>What is the central green structure prior to folding of the embryonic plate?</p>
<p>Notochord</p>
<p>What is the analogous structure to the notochord after folding?</p>
<p>Neural Tube</p>
<p>What is the name of the layer of ectoderm indicated?</p>
<p>Neural Plate</p>
<p>Which ectodermal cells migraine into the pockets shown?</p>
<p>Neural crest cells</p>
<p>What does the endoderm fold to form?</p>
<p>Gastrointestinal Tube</p>
<p>The optic pit forms at which day of gestation?</p>
<p>Day 23</p>
<p>What is the optic vesicle?</p>
<p>anterolateral outpouching of primitive brain stem</p>
<p>When does the optic vesicle form the globe?</p>
<p>evaginates on day 25 and becomes the globe</p>
<p>On which day does the optic vesicle induce the lens placode?</p>
<p>Day 25</p>
<p>Name some of the possible disordersthat can arise from abnormalities in envagination of the optic vescile.</p>
<ul> <li>anophthalmia</li> <li>cyclopia (synophthalmia)</li> <li>congenital cystic eye</li> <li>congenital nonattachment of the retina</li></ul>
<p>Name 4 disorders that are associated with synopthalmia</p>
<p>Apical forebrain lesions such as synophthalmia are associated with arrhinencephaly, proboscis, ethmocephaly, trisomy 13</p>
<p>How does the optic cup develop?</p>
<p>develops embryologically as an anterolateral evagination of the forebrain</p>
<p>What does the inner layer of the optic cup become?</p>
<p>Inner layer becomes the retina</p>
<p>What does the outer layer of the optic cup become?Outer layer becomes the retinal pigment epithelium</p>
<p>Outer layer becomes the retinal pigment epithelium</p>
<p>What does the potential space between the inner and outer layer of the optic cup become?</p>
<p>Potential space between the two becomes the SUBRETINAL SPACE (which was the cavity of the neural tube)</p>
<p>What do cells at the anterior margin of the optic cup form?</p>
<p>the posterior pigment epithelium of the iris</p>
<p>As the optic cup forms, what do cells between the future iris and the future retina form?</p>
<p>the ciliary body</p>
<p>What does the lens pit form before it bcomes the Lens vesicle?</p>
<p>Lens pore</p>
<p>where is the embryonic fissure located on the optic cup?</p>
<p>undersurface</p>
<p>When does the embyonic fissure close?</p>
<p>closes on day 33 allowing pressurization of globe</p>
<p>Where does the closure of the embryonic fissure begin?</p>
<p>Closure occurs first in midzone/equator, then extends posteriorly and anteriorly</p>
<p>what embronic tissue uses the embyonic fissure as a portal to enter the eye?</p>
<p>Embronic fissure serves as portal for mesoderm to enter eye (i.e. hyaloid artery)</p>
<p>What is it called when the embyonic fissure fails to close?</p>
<p>Coloboma</p>
<p>What is the inheritance pattern of colobomas?</p>
<p>sporadic or autosomal dominant (AD)</p>
<p>What is the typical quadrant location of a coloboma?</p>
<p>typical (located in inferonasal quadrant)</p>
<p>If a coloboma involves the retina and choroid what other conditions or syndromes can it be associated with?</p>
<p>associated with basal encephalocele, cleft palate, and CHARGE syndrome)</p>
<p>Is eyelid coloboma associated with closure of the embryonic fissure?</p>
<p>No</p>
<p>What do you call a small, abnormal eye with cystic expansion extending postioerly into theorbit?</p>
<p>Microphthalmos with cyst</p>
<p>Where does the cyst in microphthalmos with cyst typically arise?</p>
<p>Arises in area of and external to a choroidal coloboma</p>
<p>What kind of tissues are contained in the cyst with microphthalmos with cyst?</p>
<p>cyst usually contains dysplastic neuroectodermal tissue and may not directly connect with the eye</p>
<p>T/F: an optic pit is a coloboma?</p>
<p>True, an optic pit is considered an atypical coloboma</p>
<p>What abnormality is associated with optic pit?</p>
<p>basal encepholocele</p>
<p>Through wich structure does the hyaloid artery enter the eye?</p>
<p>embryonic fissure</p>
<p>What stucture does the hyaloid artery form?</p>
<p>vasa hyaloidea propria</p>
<p>what does thevasa hyaloidea propria supply blood to?</p>
<p>primary vitreous</p>
<p>At what gestational age does the intravitreal portion of the hyaloid artery regress?</p>
<p>8.5 months</p>
<p>What does the intraneural portion of the hyaloid artery form?</p>
<p>central retinal artery</p>
<p>What supplies blood flow to the posterior lens in embryologic development?</p>
<p>Posterior tunica vasculosa</p>
<p>At what gestational age does retinal vscular devlopement begin?</p>
<p>16th week</p>
<p>what cell type located next to the hyaloid artery formcapillary network, then form arteries and veins</p>
<p>mesenchymal cells</p>
<p>in what pattern do retinal vessels grow?</p>
<p>vessels grow centrifugally from optic disc</p>
<p>When do retinal blood vessels reach the ora serrata?</p>
<p>Nasal: 8 months</p>
<p>Temporal: 1-2 months later</p>
<p>what percentageof normal neonates have a patent hyaloid artery?</p>
<p>3%</p>
<p>Name the 4 remnants of hyaloid vasculature system</p>
<ol> <li>Bergmeister Papillae</li> <li>Peripapillary Loop</li> <li>Mittendorf's Dot</li> <li>Peristent Pupillary membrane</li></ol>
<p>Where is a Bergmeister papillae located?</p>
<p>At the optic nerve head</p>
<p>Describe how the bergmeister papillae interacts with the hyaloid artery-glial sheath of Bergmeister envelops posterior third of hyaloid artery and begins to atrophy during 7th month</p>
<p>glial sheath of Bergmeister envelops posterior third of hyaloid artery and begins to atrophy during 7th month</p>
<p>What is seen if the glial sheath of the bergmeister papillae does not fully regress?</p>
<p>epipapillaryveil</p>
<p>From what structure does the peipapillar loop extend?</p>
<p>optic nerve head</p>
<p>What ocular conditions is one at increased risk for if a Peripapillary loop is present?</p>
<p>risk of artery obstruction or vitreous hemorrhage</p>
<p>Where is a mittendorf's dot located?</p>
<p>at the posterior lens capsule</p>
<p>what does the mittendorf's dot represent?</p>
<p>location where thehyaloid artery is attached to posterior tunica vasculosa lentis</p>
<p>what does a persistent pupillary membrane represent?</p>
<p>remnants of anterior tunica vasculosa lentis</p>
<p>Which cells eventually form the optic disc?</p>
<p>Primative epithelial papillae-cells from inner layer of optic cup at superior end of embryonic fissure</p>
<p>Axons of which cell type grow through the primartive epithelial papillae?</p>
<p>ganglion cells</p>
<p>Does myelination of the optic nerve start centrally or peripherally?</p>
<p>centrally</p>
<p>At what gestational age does myelination of the optic nerve reach the chiasm?</p>
<p>7.5 months</p>
<p>At what gestational age does myelination of the optic nerve reach the lamina cribrosa?</p>
<p>birth</p>
<p>At what gestational age ismyelination of the optic nerve complete?</p>
<p>approximately 1 month after birth</p>
<p>What is the embronic structure that is contiguous with the retinal ILM that covers the optic nerve?</p>
<p>Inner limiting membrane of Elschnig</p>
<p>Why can newborns optic nerves appear exaggeratedly cupped initially?</p>
<p>ON may show deceptively exaggerated cupping because nerve fibers posterior to lamina cribrosa are incompletely myelinated at birth</p>
<p>What systemic condition is associated with optic nerve hypoplasia?</p>
<p>DeMorsier's Syndrome</p>
<p>What percentage of patient's with DeMorsier's Syndrome have pituitary abnormalities?</p>
<p>13%</p>
<p>Which 3 ocular strutures produce the vitreous?</p>
<ol> <li>lens</li> <li>retina</li> <li>walls of the hyaloid artery</li></ol>
<p>What type of embyonic cells are contained in the vitreous?</p>
<p>mysechymal cells</p>
<p>What forms the primary vitreous?</p>
<p>hyaloid vascular system</p>
<p>whatblood vessels systemmake up the hylaloid vascular system (aka vasa hyaloidea propria)?</p>
<p>hyaloid canal</p>
<p>hyaloid vessels</p>
<p>posterior portions of tunica vasculosa lentis</p>
<p>What eventually replaces the primary vitreous?</p>
<p>secondary vitreous</p>
<p>What is the disease state caused by failure of the primary vitreous to regress?</p>
<p>persistent hyperplastic primary vitreous (PHPV)</p>
<p>By which ocular structureis the secondarty vitreous formed?</p>
<p>the retina</p>
<p>What is the name of the area that extends from the disc into the vitreous?</p>
<p>Area of Martegiani</p>