Flashcards in Teratogens / Early Fetal Development (HOX, etc.) Deck (18):
Which 3 antibiotic classes are potentially teratogenic?
1. Fluoroquinolones (tendon weakness, malformation)
2. Aminoglycosides (hearing loss)
3. Tetracyclines (discovered teeth)
What 6 drugs are Cat. X?
2. Warfarin (use heparin)
4. Isoretinoic acid
When is 4 chambered heart seen?
When does fetal movement begin?
When does ext genitalia resemble the sex of fetus?
When do limb buds begin to form?
4 weeks, 4 limbs
What side teratogenic effect do the anti-epilectic drugs carbamazepine and valproic acid have?
Neural tube defects--> if can't stop the med before pregnancy, begin folate supplements months prior to pregnancy
What abnormality can lithum cause to a fetus?
Ebstein malformation--> a type of cardiac defect
What 2 drugs can increase the risk of spontaneous abortion?
1. Isoretinoic acid
2. Warfarin (give heparin to anti-coagulate instead)
What two drugs can cause limb hypoplasia in an infant?
1. Cyclophosphamide (alkylating agent)
Mutation in what HOX gene can cause synpolydactyly?
HOXD-13 (extra digits and are fused together)
Which gene is responsible for correct Anterior - posterior (cranial/caudal) organization during development?
Sonic hedgehog gene
*produced at base of limbs in Zone of Polarizing Activity
What gene is responsible for appropriate dorsal/ventral organization of body during development?
*produced at apical ectodermal ridge (thickened ectoderm at distal end of each developing limb)
What gene is responsible for the elongation of limbs?
FGF gene (stimulates mitosis of underlying mesoderm)
*defects in FGF3 receptor = achondroplasia
What is the function of HOX genes in general?
Involved in segmental organization of embryo in a cranial caudal fashion; mutations may result in appendages in the wrong locations
By what week do all three germ layers exist in the embryo?
Week 3; 3 = trilaminar disc
*gastrulation is the process that forms this trilaminar disc; starts with the epiblast invaginating to form the primitive streak
Wat embyronic structure secretes Hcg?
Syncytiotrophoblast (within week 1)