Embryo Flashcards
What are the three kidneys that develop?
Pronephros
Mesonephros
Metanephros
What is the role of the pronephros?
Develops in early week 4
Forms pronephric ducts and pronephric tubules
Degenerates in late week 4
Not functional
What is the role of the mesonephros?
Appears in lat week 4 and is functional until week 11
Forms the mesonephric ducts and mesonephric tubules
What is the role of the metanephros?
Begins to develop in week 5 and is functional and definitive
Forms the ureteric bud (AKA the metanephric duct or metanephric diverticulum)
Forms the Metanephrogenic blastema (or mass) (AKA Metanephric Cap)
Ureteric bud forms what?
the collecting system (calyces and renal pelvis
Metanephric cap forms what?
Nephron
What is Unilateral Renal Agenesis?
Development of only one kidney
More common in males (usually left kidney is missing)
Due to ureteric bud abnormality
What is bilateral renal agenesis?
Both kidneys fail to develop
Associated with oligohydramnios (reduced amniotic fluid, fetus can’t produce urine which adds to amniotic fluid)
Can survive with dialysis and kidney transplant
When do kidneys ascend to adult position?
Week 9, results from caudal growth of embryo, and rotates 90 degress during ascent
Kidneys receive blood from vessels closest to them through ascent
What is Pelvic Kidney?
Ectopic Kidney (out of normal position) - located in pelvis, did not ascend properly
Lattuce of vessels blocks ascent
What is horshoe kidney?
Kidneys are attached to each other and this prevents them form ascending due to the Inferior mesenteric Artery (IMA)
What is cystic kidney disease?
Two kinds, Autosomal recessive polycycstic disease and multicystic dysplastic kidney disease
Cysts form in kidney mpeding function
What is the ureter derrived from?
Mesonephric and metanephric ducts
What is the bladder derived from?
Hindgut endoderm
What is the trigone derived from?
Mesoderm
What are the three parts of the urogenital sinus?
- Vesicle part: bladder
- Pelvis Part: Just urethra in females, prostatic and membranous urethra in males
- Phallic Part: Lining of vaginal vestibules and spongy urethra
Describe the three allantois abnormalities
Urachal Fistula (patent urachus): No umbilical ligament, Urinary bladder continuous with belly button; urine leaks out belly button when voiding
Urachal Cyst: Rarely causes problems, cyst connected along the umbilical ligament
Urachal Sinus: No umbilical ligament, bladder not continuous with belly button, but belly button is very deep.
What is exstrophy of the bladder?
Ectopic bladder (bladder outside body)
Arises during 4th week of body folding
Defective closure of abdominal wall
What is epispadias?
Improper location of genital tubercles (forms penis) caudal to cloacal membrane. Urethral opening on upper side of penis rather than tip
Patent urachus
Urinate out belly button
What tissue forms the suprarenal glands?
Medulla (think brain; think neuro): neural crest - chromaffin cells
Capsule: Mesonephric mesoderm (intermediate mesoderm)
Cortex forms in week 6 from coelomic epithelium (somatic mesoderm)
