11/20 Development Of Urinary System Flashcards
Formation of multiple sets of kidneys is in weeks?
4-8
Relocation of kidneys in urinary development happens in week?
9
Significant urine formation in urinary development happens in week?
11
Nephrogenesis occurs when prenatally?
Through week 36
When is the critical period for kidneys?
Most of human gestation (through week 36)
Fewer nephrons is associated with an increased risk for?
Hypertension
After birth, the glomerular filtration rate increases rapidly due to
decreased renal vascular resistance and increased renal blood flow
What is the general process of renal development?
Clusters of cells and ducts form, connected to cloaca
Columns of tissues use ducts and develop primitive, temporary nephrons
Kidneys form in pelvic region (at caudal end of ducts) and develop permanent nephrons
Kidneys relocate to their final positions
Cloaca is divided and part of it forms urinary bladder
During the urogenital ridge stage of renal development what is the state of sexual development?
Embryo is in undifferentiated state of sexual development, phenotypically identical regardless of genetics
What is the urogenital ridge and what does it contain?
Elevated intermediate mesoderm on either side of the dorsal aorta, along the posterior abdominal wall
Contains: Nephrogenic cord, Gonadal ridge
What does endoderm do in the urogenital ridge of renal development?
Endoderm forms epithelial lining and glands of the urinary bladder
Neural crest cells may play a minor role
How many sets of kidneys develop in weeks 4-5? How many of these become the permanent kidneys?
3 sets develop
1 set becomes permanent kidneys
What is the pronephroi set of kidneys? where are they?
Practice set of kidneys, used to develop a duct system
• On same plane as pericardial cavity
What are the three sets of kidneys that develop? In which weeks?
Weeks 4-5
Pronephroi, mesonephroi, metanephroi
What are the mesonephroi set of kidneys?
Temporary set of kidneys, used until the metanephroi are complete
What are the metanephroi set of kidneys?
Permanent set of kidneys
When are the pronephroi present? What is the purpose?
Present only in week 4
Purpose is to create tubular structures to be used later
What do the pronephroi contain?
Nonfunctional cell clusters in cervical region
Pronephric ducts
What are the pronephroi nonfunctional cell clusters made of? Do they persist?
made of pronephric tubules that degenerate
Where do the pronephric ducts run? Do they persist?
run from pronephric tubules to cloaca
persist and are used by mesonephroi
When are the mesonephroi present?
Appear late week 4
Degenerate after week 11
What is significant about week 11 in relation to renal function?
Urine formation contributes to amniotic fluid
What do the mesonephroi consist of?
Long columns of tissue caudal to pronephros
Made of mesonephric nephrons and tubules
Are the mesonephroi functional?
temporarily functional until metanephroi take over in week 11
Where do the mesonephric ducts run?
From mesonephric nephrons and tubules to cloaca
When do metanephroi appear? Become functional?
Appear in early week 5
Take a month to become functional, and take over urine production from mesonephroi in week 11
What do metanephroi develop from?
Develop from intermediate mesoderm in two ways:
Ureteric bud and metanephric blastema
What is the ureteric bud?
lateral outgrowth of mesonephric duct near cloaca
What is the metanephric blastema?
Renogenic tissue surrounding ureteric bud
Interactions between what forms the metanephroi?
Ureteric bud epithelium and cells within metanephric blastema
What is metanephroi development dependent on?
Retinoic acid
Renogenic malformations can be caused by retinoic acid excess or deficiency?
Excess and deficiency can both cause malformations
What are some other developing tissues that are dependent upon proper levels of retinoic acid?
Neural tube development