Embryology lecure 1

Flashcards by mccallkb, updated more than 1 year ago
Created by mccallkb over 6 years ago


Anatomy Flashcards on Embryology lecure 1, created by mccallkb on 07/26/2014.

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Question Answer
morulla 16 cell stage of zygote with an inner cell mass and outer cell mass
blastomeres the dividing zygote from 30 hours until 4 days (morula 16-cell) of development
blastocyst stage of embryogenesis at the time of implantation where outer trophoblast cells form a fluid-filled sphere with a small group of embryoblast cells, the inner cell mass, at one pole
embryoblast cells of the inner cell mass
trophoblast cells of the outer cell mass which flatten to form the epithelial wall of the blastocyst
embryonic stem cells (ES cells) pluripotent cells, can form any cell or tissue type, derived from the inner cell mass of the embryo and have the potential for curing a variety of diseases
cytotrophoblast the inner layer of mononucleated cells in the trophoblast
syncytiotrophoblast the outer multinucleated zone without distinct cell boundaries in the trophoblast
hypoblast layer a layer of small cuboidal cells adjacent to the blastocyst cavity derived from cells of the inner cell mass or embryoblast
epiblast a layer of high columnar cells adjacent to the amniotic cavity derived from the cells of the inner cells mass or embryoblast
extraembryonic mesoderm cells derived from yolk sac cells form a fine loose connective tissue which eventually fills all of the space between the trophoblast externally and the amnion and exocoelomic membrane internally
chorionic cavity a new space formed when large cavities develop in the extraembryonic mesoderm and become confluent
primary villi cellular columns with syncytial covering protruding from the cytotrophoblast to the syncytiotrophoblast
connecting stalk mesodermal connection that connects the embryo to the placenta. It contains the allantois and umbilical vessels and will be incorporated into the umbilical cord with the yolk sac (vitelline) stalk (duct)
ectopic pregnancy implantation that occurs outside the uterus. Ex: In the rectouterine pouch, on the mesentery, in the uterine tube, or in the ovary
hydatidiform mole the trophoblast develops and forms placental membranes, although little or no embryonic tissue is present. They secrete high levels of hCG (human chorionic gonadotropin) and may produce benign or malignant tumors
gastrulation 3rd week of gestation, the process that establishes all 3 germ layers (ectoderm, mesoderm, and endoderm) in the embryo
primitive streak formation of this marks the beginning of gastrulation. appears on the surface of the epiblast
primitive node cephalic end of the streak and consists of a slightly elevated area surrounding the small primitive pit
primitive pit depression in the primitive node
notochord extended column of midline cells lying immediately ventral to the floor plate of the central nervous system and extending from the hypophysis to the end of the spinal cord.
prechordal plate collection of mesoderm cells lying between the oropharyngeal membrane and the cranial end of the notochord. These cells represent some of the first to pass through the primitive streak and are important for forebrain induction using SHH as a signal molecule
cloacal membrane formed at the caudal end of the embryo from adhesion between epiblast and hypoblast cells. Later, it covers the cloaca and eventually breaks down to form openings into the urogenital sinus and anus
endoderm one of the three basic germ layers that form the gut and its derivitaves
ectoderm one of the three basic germ layers that forms skin, the central nervous system, hair, and many other structures
mesoderm one of three basic germ layers that form blood vessels, bone, connective tissue, and other structures
anterior visceral endoderm (AVE) collection of endoderm cells at the cranial end of the bilaminar disc responsible for inducing the head region through secretion of transcription factors including, OTX2, LIM1, and HESX1.
situs inversus complete reversal of left- and right- sidedness of the organs in the thorax and abdomen
laterality sequences right and left sides are established during gastrulation in the third week of development. Patients with defects in sidedness, such that they are primarily bilaterally right or left sided, have this.
primary villi present in trophoblast that consis of a cytotrophoblastic core covered by a cyncytial layer
secondary villi mesodermal cells penetrate the core of primary villi and grow toward the decidua.
tertiary villi (definitive placental villus) mesodermal cells in the core of the villus differentiate into blood cells and small blood vessels, forming the villous capillary system
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