Ch. 64 Flashcards
3 sets of excretory organs that develop in the embryo:
Pronephros
Mesonephros Metanephros
Only 3rd set remains as permanent kidney
First pair of kidneys
o Pronephros
o Rudimentary
o Nonfunctional
Second pair of kidneys
o Mesonephros
o Function for short time during early fetal period
o Degenerate after replaced by metanephros [permanent kidneys]
Urine formation begins
11-12th week
Urine is excreted into
Amniotic fluid
Kidneys do not need to _ in uterus in the means of waste filtration
Function
_ eliminates waste from the fetal blood
Placenta
Kidneys must be able to _ after birth
Assume their waste excretion role
Arterial vascular supply to the kidneys comes from
arteries that arise from the aorta
o These vessels usually disappear when kidneys ascend
Some may persist
Accounts for variations found in renal arteries, 25% of adult kidneys have 2-4 renal arteries
Kidneys initially lie
Very close together in the pelvis
Kidneys gradually migrate into the
Abdomen and separate from one another
Normal kidney migration is completed by
The 9th week
Early development of external genitalia is
similar for both sexes
External genitalia are fully differentiated by
12th weeks
In week 4, the genital tubercle develops at the
cranial end of the cloacal membrane