Term
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Definition
| The outermost layer of cells of the blastocyst that attaches the fertilized ovum to the uterine wall and serves as a nutritive pathway for the embryo. Also called trophoderm. |
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Term
| Totipotent vs Pluripotent |
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Definition
Totipotent -- can become anything
Pluripotent -- can become many things |
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Term
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Definition
| Differentiation of cells and tissues in the early embryo which results in establishing the form and structure of the various organs and parts of the body. |
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Term
| 3 types of cell signaling |
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Definition
Diffusible signal – morphogen
• BMPs
• Wnt
– Cell-‐matrix
• integrins
– Cell-‐cell
• induction
• Notch-‐delta |
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Term
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Definition
| A cell secretes a substance that instructs a neighboring cell to adopt cell fate X. |
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Term
| How different combinations of cell signals can yield different outcomes (4) |
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Definition
• Pattern formation (organization)
• Migration
• Proliferation (growth)
• Determination (differentiation) |
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Term
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Definition
| Proteins that are made that bind DNA and regulate gene transcription. |
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Term
| Important Morphagens We Must Know (4) |
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Definition
•Retinoic acid
– Anterior-‐posterior axis, limb patterning
• Transforming Growth Factor (TGF)-‐β/Bone Morphogenic Proteins (BMPs)
– Dorsal-‐ventral
axis, cell fate, organogenesis
• Hedgehog proteins
– Neural tube
D-‐V patterning, limb (digit) formation
• Wnt/β-‐catenin
– Posterior nervous system, planar cell polarity |
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Term
| Fertilization Age vs Gestational Age |
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Definition
Gestational age is fertilization age + 2 weeks.
Fetilizational age used in embriology; Gestational age used clinically. |
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Term
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Definition
| The spherical embryonic mass of blastomeres formed before the blastula and resulting from cleavage of the zygote/fertilized ovum. |
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Term
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Definition
| The strong membrane that forms around an ovum as it develops in the ovary. The membrane remains in place during the egg's travel through the fallopian tube. To fertilize the egg, a sperm must penetrate the thinning zona pellucida. If fertilization takes place, the zona pellucida disappears, to permit implantation in the uterus. |
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Term
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Definition
– Multinucleated, no cell membranes
– Invasive
– produces hCG
– Doubles every 48h for 1st month |
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Term
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Definition
| The membrane of the amniotic sac specifically. |
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Term
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Definition
| The upper layer of the bilaminar embryonic disc present during the second week; it gives rise to ectoderm. |
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Term
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Definition
| “Stem cells” of the trophoblast; The inner layer of cells of the trophoblast of the early mammalian embryo that gives rise to the outer surface and villi of the chorion. |
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Term
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Definition
| The lower layer of the bilaminar embryonic disc in a human embryo, present during the second week, that gives rise to the endoderm. |
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Term
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Definition
| A short lived combination of hypoblast cells and extracellular matrix; It surrounds the exocoelomic cavity. I.E. it lines the inner surface of the cytotrophoblast. Becomes the yolk sac. |
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Term
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Definition
| Series of mitotic divisions without cell growth; Zygote becomes a morula made up of blastomeres |
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Term
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Definition
| Blastomeres change shape – more epithelial; Line up tightly together, just before blastocyst formation |
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Term
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Definition
A cluster of cells representing multiple cell divisions that have occurred in the fallopian tube after successful fertilization of an ovum by a sperm. This is the developmental form which must leave the fallopian tube, enter the uterus, and implant itself in the uterus to achieve actual pregnancy.
Made up of embryoblast, blastocoel (blastocyct cavity), trophoblast, and zona pellucida. |
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Term
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Definition
Usually Around day 6
Blastocyst invades endometrium
• Trophoblast proliferates and differentiates into
– Cytotrophoblast
– Syncytiotrophoblast
• Embryoblast differentiates into
– Epiblast
– hypoblast
Embryonic cells flatten forming a bilaminar disk (Hypoblast, Epiblast)
• Begins week of 2s
Also forms two cavities
– Amniotic cavity
– Umbilical vesicle (yolk sac) |
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Term
| Endometrial Decidual Cells (2) |
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Definition
– Engulfed by syncytiotrophoblast
– Early source of nutrients |
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Term
| [DIAGNOSTICS] Signs of Ectopic Pregnancy (4) |
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Definition
1. hCG not doubling every 48 hours
2. Spotting around time of period* or abnormal period, but not always recognized
3. Abdominal pain
4. Referred shoulder pain
* Especially in tubal pregnancies
* NOTE: spotting in placenta previa is more~~~ |
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Term
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Definition
| Human Chorionic Gonadotropin |
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Term
| Human Chorionic Gonadotropin (hCG) |
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Definition
| Maintains the development of spiral arteries in the myometrium and formation of the synctiotrophoblast. |
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Term
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Definition
| Any mesoderm in the uterus that is not involved with the embryo itself. Included are mesoderms in the amnion, chorion, yolk sac, and connecting stalk; Develops as bilaminar embryo pulls away from cytotrophoblast. |
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Term
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Definition
| A cavity external to the developing embryo that forms between the mesoderm of the chorion and that covers the amniotic cavity and yolk sac; Becomes chorionic cavity/sac; Also called exocoelom. |
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Term
| Gestational trophoblastic neoplasia (GTD) |
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Definition
| A group of neoplastic disorders that originate in the placenta, including hydatidiform mole, chorioadenoma destruens, and choriocarcinoma. |
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Term
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Definition
| A hydatidiform mole in which molar chorionic villi enter the myometrium or parametrium or, rarely, are transported to distant sites, most often the lungs; an epithelial cell tumor of the outermost fetal membrane that is the intermediate in the malignant development of a hydatid mole to invasive choriocarcinoma. |
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Term
| [DIAGNOSTICS] Hyatidiform Mole (3) |
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Definition
• Marked proliferation of trophoblast
–usually blastocyst isn’t formed (or dies)
• hCG levels continue to rise (excessively)
–may be mistaken as pregnancy
• Preeclampsia in 1st trimester
–proteinuria and hypertension |
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Term
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Definition
A type of cancer germ cell containing trophoblast cells; usually of the placenta. May also arise in a testicle or ovary.
• Uncommon, often curable if detected early
• 50% of time follows a hydatidiform mole |
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Term
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Definition
| Finger-like projections that emerge from the outer sac of an embryo; they will eventually form the placenta. |
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Term
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Definition
As the embryo grows and folds, the umbilical vesicle gets pinched and incorporated into the embryo as gut tube and the walls contribute to the umbilical cord
• Germ cells also originate in umbilical vesicle and migrate into the embryo just before the formation of the gonads. |
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Term
| What 7 things happen during Gastrulation? |
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Definition
Beginning of morphogenesis
Cell shape changes and rearrangement
Cell movement
Changes in cell contact properties
Development of three germ layers
A bit of overlap with neurulation
As gastrulation finishes, neurulation begins |
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Term
| Trilaminar Embryo (3 germ layers) |
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Definition
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Term
| What 5 things does the ectoderm become? |
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Definition
| Skin, nervous system, eye, inner ear, cerebral connective tissue |
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Term
| What 3 things does the endoderm become? |
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Definition
Endoderm
Respiratory and GI epithelium, some glands |
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Term
| What 5 things does the mesoderm become? |
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Definition
| Skeletal muscle, blood, cardiovascular endothelium and muscle, connective tissue |
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Term
| 3 Cavities (what really happens at the end of week 2) |
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Definition
Umbilical vesicle
Amniotic sac
Chorionic sac (was extraembryonic coelom) |
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Term
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Definition
An ectodermal ridge in the midline at the caudal end of the embryonic disk from which the intraembryonic mesoderm arises.
Note: the primitive streak is just a sign of gastrulation; it does not become anything and in fact disappears after gastrulation is complete |
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Term
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Definition
Some cells that move through the primitive streak migrate cranially through the mesoderm along the midline
Begins centrally and proceeds cranially as gastrulation is completing
Extends caudally once gastrulation is complete and primitive streak recedes
Important signaling structure subsequently signals neural tube and somite formation |
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Term
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Definition
A segmental mass of mesoderm in the vertebrate embryo, occurring in pairs along the notochord.
These structures give rise to the vertebrae and differentiate into various tissues of the body, including the voluntary muscle, bones, connective tissue, and dermal layers of the skin. |
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Term
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Definition
Formation of the neural tube
-Notochord induces ectoderm to form neural plate
-Epithelial cells thicken and fold
-Neural crest cells form
Also developing at this time:
-Primitive heart tubes, blood vessels
-Somites (lateral signaling from notochord)
-Embryonic folding (dorsoventral and craniocaudal) also occuring |
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Term
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Definition
A cellular band dorsolateral to the embryonic neural tube that gives origin to the spinal ganglia and other structures.
As neural tube folds, dorsal cells pinch off and become sensory ganglia; Also contribute to pigment cells, adrenal gland, heart and connective tissue of the head |
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Term
| Neurulation Defects (3 types) |
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Definition
Neural tube defects, vary in severity and location
-Spina bifida (variations)
-Anencephaly or meroencephaly – absence of most of the brain
Chordoma - a rare tumor that develops from the fetal notochord. It is usually located in the midline, behind the sella; it is slow growing but highly invasive.
Remnants of the notochord
Cranial or sacral
Late development in men (>50)
Neural crest defects
many organ systems, especially heart |
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Term
| Malformations of Gastrulation (2) |
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Definition
Caudal dysplasia
-Varies greatly in severity – fused vertebrae or legs
-Abnormal mesoderm migration
-May be associated with cranial, renal, cardiovascular and anal defects
Sacrococcygeal teratoma
-Remnants of the primitive streak
-More common in females, cranial
-Usually very malignant – must be removed |
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Term
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Definition
| A primitive mesenchymal tissue that develops into bone marrow and blood vessels. |
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Term
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Definition
Mesenchymal cells form angioblast blood islands in umbilical vesicle and other extraembryonic mesoderm – week 3
Also happens slightly later in embryo in lateral mesoderm
Angioblasts flatten and form endothelial lining
Budding and fusing arranges blood vessels
Endothelial cells become blood cells in vessels along umbilical vessel |
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Term
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Definition
Paired endocardial tubes develop from mesenchymal cells in cardiogenic region
During folding tubes fuse and form primitive heart tube and join with other vessels
Heart begins to beat and blood is pumping at the end of the 3rd week or very beginning of the 4th week |
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Term
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Definition
| One of a large and very important family of adhesion molecules that promote stable interactions between cells and their environment. The integrins also act as cellular sensor and signaling molecules. |
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Term
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Definition
| The cellular, outermost extraembryonic membrane, composed of trophoblast lined with mesoderm; it develops villi, becomes vascularized by allantoic vessels, and forms the fetal part of the placenta. |
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Term
| Progression of embryo from week 0 to beginning of week 2 |
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Definition
Begins as oocte
Becomes fertilized zygote
Cleaves to become a morula made of blastomeres
Compacts to becom blastocyst made of embryoblast (becomes stem cells), trophoblast (beomces placenta), zona pellucida, and blastocoel (blastocyct cavity)
Begin week 2
Implants and forms synctiotrophoblast (from trophoblast), bilaminar embryonic disc (from embryoblast) made of epiblast and hypoblast, amnion and amniotic cavity form, and blastocoel (blastocyct cavity) becomes exocoelomic cavity & membrane briefly before becoming the primary umbilical vesicle, closing plug forms, cytotrophoblast forms from trophoblast, and between disc amnion and cytotrophoblast is the extraembryonic mesoderm |
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Term
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Definition
| A fibrinous coagulum of blood that fills the defect in the endometrial epithelium created by implantation of the blastocyst. |
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Term
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Definition
a membranous sac attached to an embryo, providing early nourishment.
Also known as the exocoelomic cavity. |
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Term
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Definition
Any of the germinal disk cells of the inner cell mass in the blastocyst.
Differentiates into
– Epiblast
– hypoblast
Embryonic cells flatten forming a bilaminar disk (Hypoblast, Epiblast) |
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