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in the embryonic phase how many wks are there?
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Initiation of nervous system, basic body plan and organogenesis happens in what wks?
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Test1GeneticsWk8
Developmental Genetics and Prenatal disorders
| Question | Answer |
|---|---|
| in the embryonic phase how many wks are there? | first 3 wks: Blastocyst, Implantation, gastrulation formation of 3 germ layers |
| Initiation of nervous system, basic body plan and organogenesis happens in what wks? | 4 to 8 |
| Fetal phase | Wks 9 to 40 |
| All cells undergo specifiction and determination to achieve their ultimate differentiated phenotype except what two cells? | Germ and Stem |
| Cells have already become committed to the point that removal of a portion of an embryo will not allow normal embronic development. *Conjoined Twins | Mosaic Development |
| Transcription factors | control the expression of other genes |
| Mutation of a gene encoding a transcription factor would cause what to happen? | Synpolydactyly (webbing and extra digits) // bone malformations of hands,wrist,feet, and ankles |
| bad cell to cell signaling by cell surface receptor and a ligand can cause birth defects name some? | Achondroplasia, craniosynostoses, Polycyctic Kidney Disease |
| Cell Migration | Programmed cell movement especial important in the central nervous system, which is developed from the neural tube |
| Cell Migration abnormalities name 3. | Miller-Dieker syndrome, Hirshsprung disease, Waardenburg Syndrome |
| what occurs during development of the immune system to elimnate lymphocyte lineages that react to self, preventing autoimmune disease? | Apoptosis - critical for tissue remodeling during morphogenesis (separation of digits example) |
| What are 3 major categories of birth defects (dysmorphology) | Malformations, Deformations, Disruptions |
| what results from intrinsic abnormalities in one or more genetic programs operating in development? | Malformations (extra fingers) |
| Deformations (common in 2nd Trimenster) | Caused by extrinsic factors impinging physically on the fetus during development (ex: Arthrogryposes contractions of the joints of the extremities) |
| Result from destruction of irreplaceable normal fetal tissue due to vascular insufficiency, trauma, or teratogens. | Disruptions (more difficult to treat) |
| Give % : Complex inheritance ? // Single gene mutations ? // Chromosomal imbalance ? | Complex 50% // Single gene 20% // Chromosomal 25% |
| What is a single causative agent results in abnormalities of more than one organ system in different parts of the embryo or in multiple structures that arise at different times during intrauterine life? | Pleiotrophy (ex: Rubinstein-Taybi Syndrome) |
| What would be 3 indications for prenatal testing by invasive procedures? | Advanced Maternal age, Previous child with de novo chromosomal aneuploidy, a parent with a structural chromosome abnormality, Family history of X-Linked disorder, Risk of neural tube defect in first degree relative |
| What are the 4 invasive Test? | Chorionic Villus Sampling (CVS) // Amniocentese // Cordocentesis // Pre-implantation genetic diagnosis |
| Amniocentesis typically performed when? | 15 or 16th wk |
| Biopsy of tissue from chorionic villi performed b/t what time frame? | 10th and 12th weeks |
| Combining results fo 1st and 2nd trimester testing to increase ability to detect autosomal trisomies (especially Trisomy21) is known as what testing? | Stepwise Sequential Testion |
Created by:
cmuox2000
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