Repro/Embryology Flashcards
Origin of anterior pituitary
Surface ectoderm (Rathke’s pouch -> adenohypophysis). Note that the neurohypophysis (posterior pituitary) comes from neuroectoderm
Origin of parafollicular cells in thyroid (C-cells) and bones of the skull
Both are neural crest derived!
Birth defect from phenytoin and carbamazapine taken during pregnancy
Fingernail & phalynx hypoplasia
Mechanism by which alcohol causes fetal alcohol syndrome
Failure of cell migration
Implantation of zygote timing?
~7 days (6-10). Cleavage of monozygotic twins occurs around this same time. When it happens just after implantation -> monochorionic, diamniotic twins (most common)
Only branchial cleft that persists into adulthood?
First branchial cleft: external auditory meatus
Branchial arch 3 derivatives
CN IX: Stylopharyngeus muscle, greater horn of hyoid bone. Note most other things that will cause confusion in this area are arch 2 derivatives (CN VII).
Derivative of all intrinsic muscles of the larynx?
Mostly arch 6 (CN X, recurrent laryngeal) except for cricothyroid: arch 4 (CN X, superior laryngeal)
Adult derivatives of genital tubercle
Men: glans penis, corpus cavernosum and spongiosum (when positioned improperly develops into epispadias)
Women: clitoris and vestibular bulbs
Adult derivatives of urogenital folds
Men: ventral shaft of penis/urethra (defect in fusion causes hypospadias)
Women: labia minora (NTBCw/ labioscrotal swellings that become labia majora)
Embryologic origin of prostate gland
Urogenital sinus: note this means that DHT stimulates prostate development while testosterone stimulates devo of rest of male internal structures from Wolffian duct (mesoneprhic)
Site of urethral injury from pelvic fracture
Posterior urethral membranous urethra (immediately distal to the prostate). Anterior urethra (bulbous and penile segments) at risk from straddle injury
Name of fully mature sperm in lumen of seminiferous tubule? Options: spermatogonium, spermatids, spermatozoon, spermatocyte
Spermatozoon. Order of development: : spermatogonium, spermatocyte, spermatids, spermatozoon (“Zooming to egg”)
Most consistent part of menstrual cycle across all women
Luteal/secretory phase (post-ovulation) is exactly 14 days
3 types of estrogens and their sources
Estradiol: ovaries (most potent), Estrone: adipose, estriol: placenta (least potent)
Two middle ear muscles invovled in dampening sound and their innervation
Tensor tympani: CN V3
Stapedius muscle: CN VII
Mechanism of HPV virulence to cause cervical cancer
Inhibition of p53 (E6 gene) and inhibition of Rb (E7 gene)
Immature vs. mature teratomas (ovarian neoplasms)
Mature teratoma is benign, contains teeth, hair, etc and can contain thyroid tissue
Immature teratoma is malignant and contains neuroectoderm & embryonic-like tissue
Danazol MOA (Hint: repro/endo)
Used in treatment of endometriosis. Decreases estrogen production by ovaries and displaces testosterone from binding protein. Net hypo-estrogen, hyper-androgen affect
Most important prognostic factor in malignant breast tumors
Axillary lymph node involvement (suggests metastases)
Tender breast with inflamed looking skin that resembles an orange peel (woman is not breastfeeding). Dx?
Peau d’orange breast caused by lymphatic invasion of breast carcinoma. Neoplastic cells block lymphatic drainage, no bueno
Clomiphene MOA
Antagonist of estrogen receptors in hypothalamus. Loss of negative feedback increases GnRH secretion. Used to stimulate ovulation in PCOS
