Embryology Flashcards
Blastocyte
Hollow ball with 2 layers - trophoblast on the outside and Embryoblast on the inside
Cytodifferentiation
Development of different cell types
Ectoderm
Layer in trilaminar embyonic disc derived from epiblast layer and lining stomodeum (outer)
Endoderm
Layer in trilaminar embryonic disc derived from hypoblast layer (inner)
Epiblast Layer
Superior layer in bilaminar disc (high columnar cells)
Histodifferentiation
Development of different tissue types
Hypoblast Layer
Inferior layer in bilaminar disc (cuboidal cells)
Meiosis
Process of reproductive cell production that ensures correct number of chromosomes
Mitosis
Cell division that occurs in phases and creates 2 daughter cells
Mesoderm
Embryonic layer located between endoderm and ectoderm (middle)
Morphodifferentiation
Development of the differing structure or shape
Morula
Ball of cells
Neural crest cells
Specialized group of cells developed from the neuroectoderm that migrate from the crests of the neural folds and disperse to specific sites within the mesenchyme
Neuroectoderm
Specialized group of cells that differentiates from the ectoderm
Primitive Streak
Furrowed, rod-shaped thickening in middle of embryonic disc. Causes the disc to have bilateral symmetry
Somites
Paired cuboidal aggregates of cells that develop along the midline of the neural tube
Zygote
Fertilized Egg
Branchial Arches
Six stacked bilateral swellings of tissue that appear inferior to stomodeum, including mandibular arch
Branchial grooves
Grooves between neighboring branchial arches on each side of embryo
Buccopharyngeal membrane (Oropharangeal membrane)
Membrane at cephalic end of embryo
Globular process
Intermaxillary segment (philthrum); below the lateral nasal process
Lateral nasal process
Tissue on outer part of nasal pits that forms nasal alae
Mandibular arch
Lowest dental arch with mandibular teeth OR 1st branchial arch in embryo
Mandibular symphysis
Midline area of mandible formed by fusing two mandibular processes
Maxillary process
Prominence from mandibular arch that grows superiorly and anteriorly on each side of stomodeum
Meckel’s cartilage
Cartilage that forms within each side of mandibular arch and that dissapears as bony mandible forms
Median nasal process
Middle part of the tissue growing around nasal placodes located between nasal pit
Nasal pit
Depressions in center of each nasal placode that evolve into the nasal cavities
Pharyngeal pouches
Four pairs of evaginations lining the pharynx between branchial arches
Philthrum
Vertical groove on midline of upper lip
Placodes
Areas of ectoderm found at location of developing special sense organs on the embryo
Richert’s cartilage
Forming within the 2nd branchial arch or hyoid arch and similar to that of the mandibular arch
Stomodeum
Primitive mouth in embryo
Copula
Formed from the fusion of mesenchyme of mainly the third and parts of the fourth branchial arch. Copula gradually overgrows the second branchial arch or hyoid arch to form the base of the tongue or posterior one third.
Foramen cecum
Small pitlike depression located where sulcus terminalis points backward toward pharynx; beginning of thyroglossal duct
Lateral lingual swellings
parts of developing tongue that form on each side of tuberculum impar
Lateral palatine processes
Farther from the midline of the palatine process
Median lingual sulcus
Midline depression on dorsal surface of the tongue
Premaxila
Incisive bone - bone that bears the upper incisive teeth
Primary palate
Anterior part of final palate derived from intermaxillary segment during prenatal development
Secondary palate
Posterior part of final palate formed by fusion of two palatal shelves
Sulcus terminalis
Groove located posteriorly on dorsal tongue surface
Thyroglossal duct
Temporary tube that connects thyroid with tongue base during prenatal development
Tuberculum impar
Initial part of developing tongue located in midline.
