Lecture 29 - urinary tract and adrenal embryo Flashcards
basic urinary system
kidney (filter plasma and excrete urine)
ureter (connect kidneys to bladder)
urinary bladder (stores urine)
urethra (carries urine from bladder to exterior)
what embryonic cells does the urogenital system develop from
intermediate mesoderm
what are the urogenital ridges
nephrogenic cord (urinary) genital/gonadal ridge (genital)
names of embryological kidneys
pronephros
mesonephros
metanephros
when are pronephros part of embryo
4th embryological week
what are pronephros consisted of
cervical nephrotomes and pronephric duct
TRANSITORY AND NON FUNCTIONAL
when do mesoneprhos appear
late in 4th week, functional TEMPORARILY
what do mesonephros consist of
nephrotomes >glomeruli
mesonephric tubules
mesonephric ducts
what are mesonephric ducts a remnant of
pronephros, opens into cloaca
when do mesonephros degenerate
Degenerate at end of first trimester (except for some adult male derivatives)
when do Metanephros develop and start to fucntion
develop in 5th, function in 9th
what happens after 12th week in terms of kidneys
majority of amniotic fluid is fetal urine
what are the permanent kidneys derived from
metanephric diverticulum aka uretic bud
what is the metanephric diverticulum an outgrowth of
distal mesonephric duct
what does metanephric diverticulum give rise to
ureters, renal pelvis, calices, and collecting tubules
another word for metanephric mass of intermediate mesoderm
metanephrogenic blastema
what gives rise to the nephrons
Metanephric mass of intermediate mesoderm
how do we get our permanent kidneys
Metanephric diverticulum and metanephric mass of intermediate mesoderm are interdependent and have reciprocal induction
specific interaction of uretic bud and metanephric mesoderm
Ureteric bud penetrates metanephric mesoderm to induce metanephrogenic blastema
THEN
Metanephric blastema induces ureteric bud to undergo successive branching
what does the uretic bud become
major calices (1-4 generations) minor calices (4-8 generations) collecting tubules (over 8 generations)
formation of nephrons embryologically
1) Distal end of collecting tubule (from ureteric bud) induces metanephric vesicles (from blastema)
2) Metanephric vesicles elongate into metanephric tubules
3) Distal end of metanephric tubule invaginated by glomerular capillaries
fetal kidneys
lobular in appearance
when do number of glomeruli increase until
32-35 weeks gestation
when does glomerular filtration begin
around week 9, GFR increases after birth
where do kidneys begin and end positionally
initially in pelvis, ascend into abdomen as caudal portion grows relative to cranial
STOP when reach abdomen, hilum of kidney rotates 90 degrees medially
what is the early embryonic renal artery
common iliacs
what happens to blood supply as kidneys ascend
branches involute and ner arteries arise from aorta – adult renals come from aorta
what does cloaca turn into
urorectal septum
- rectum
- urogential sinus
divisions of urogenital sinus and what they become
vesical part - most of bladder
pelvic part - urethra
phallic part - grows towards genital tubercule
urinary bladder epithelium and outer layers
epithelium: endoderm
outer layer: splanchnic mesoderm
INITIALLY CONTINUOUS WITH ALLONTOIS
what do ureters come from
metanephros
where is bladder in children vs adults
abdominal until puberty when it becomes pelvic
fate of allantois
initially continuous with bladder (contributes vesicle portion), constricts to become urachus, extends from dome of bladder to umbilicus and then becomes median umbilical ligament in adults
endoderm of urethra in males vs femals
female: endoderm of urogenital sinus
male: proximal uroginital sinus, distal epithelial growth from penis (glandular uretheral plate)
where is connective tissue/smooth muscle in urethra derived from
splanchnic mesoderm
where is the cortex of the adrenal glands derived from
mesoderm
where is the medulla in the adrenal glands derived from
neural crest cells
when do adrenals develop
6th week - intermediate mesoderm and adjacent to gonads
what does the medulla of the adrenals secrete
epinephrine and norepinephrine
cortex - outer to inner layers
zona glomerulosa (salt) zona fasciculata (sugar) Zona reticularis (sex) SALT SUGAR SEX THE LOWER YOU GO THE BETTER IT GETS
Zona glomerulosa
mineralocorticoids=salt/fluid regulation, aldosterone
Zona fasciculata
glucocorticoids=metabolism of carbs, proteins and fats, cortisol
Zona reticularis
sex steroid precursors
fetal adrenals size wise
bigger than fetal kidneys!!!
failure of kidneys to develop is called
renal agenesis
if bilateral, lethal due to pulmonary hypoplasia
POTTER SEQUENCE
kidneys dont develop so you dont have urine which means you dont dont have amniotic fluid during fetal life (get compression and pulmonary hypoplasia)
prune belly syndrome
development of urethra is bad and get folded stomach
