Embryology Flashcards
What does the urogenital system develop from?
Intermediate mesoderm
What develops into the kidney?
Metanephros
Embryological origin of adenohypophysis?
Ectoderm
What occurs during capacitation?
Cervical and fallopian tube secretions remove glycoprotein and cholesterol of acrosomal membrane
How do sperm penetrate corona radiata?
Release hyaluronidase and movement
How do sperm penetrate zona pellucida?
Releases acrosomal enzymes - esterases, neuraminidase, and acrosin
What is the zona reaction?
Release of lysosomal enzymes from cortical granules into space between zona pellucida and oocyte cell membrane which changes structure to prevent more sperm from penetrating zona pellucida
What day does the morula form?
Day 4
What day does the blastocyst form?
Day 5
How many cells does the morula have?
16
When does implantation begin?
Day 8-9
What are the cells of the zygote called?
Blastomeres
What do urethral folds form?
F - labia minora
M - ventral aspect of penis
What do genital swellings form?
F - labia majora
M - scrotum
What does the genital tubercle form?
F - clitoris
M - penis
What does the urogenital sinus form?
Urinary bladder
Urethra
F - urethral and paraurethral glands, vagina
M - prostate gland, prostatic utricle
What urinary structures does the mesonephric duct form?
Ureter, renal pelvis, calyces, collecting tubules
When do the 3 germ layers arise from epiblast?
Day 18
When does blastocyst hatch from zona pellucida?
Days 6-7
Formation of female gamete?
Oogonium -growth/maturation-> primary oocyte -meiosis I-> secondary oocyte -meiosis II-> ootid -differentiation-> ovum
Rotation of midgut?
270 deg anticlockwise
Which gamete cell type has the highest number of chromatids?
Primary oocyte (2 x 46)
Where do primordial germ cells originate?
Yolk sac endothelium
Where do paramesonephric ducts develop from?
Coelomic epithelium on urogenital ridge
Gestional age in which physiological umbilical hernia occurs?
8-10 weeks
What ensures persistence of the mesonephric duct in males?
Androgens
Closure of ductus arteriosus after birth is mediated by?
Bradykinin
Retina is derived from?
Neuro ectoderm
At what stage does the embryo enter the uterus?
8 cell stage
Layers of amnion?
5: cuboidal epithelium, basement membrane, compact layer, fibroblast layer, spongy layer of reticular tissue
Layers of chorion?
4: fibroblasts, reticular layer, basement membrane, trophoblast layer
CRL 10mm = gestational age?
7 weeks
Indifferent gonad differentiation?
Male - medullary cords develop
Female - cortical cords develop
