Lecture 29: Embryology of Urinary Tract and Adrenals

Question 1

kidneys’ purpose, location

Answer 1

filter plasma to make urine, at costovertebral angle

Question 2

hilum

Answer 2

ureters/vessels enter kidney

Question 3

urinary system track

Answer 3

kidney > ureter > urinary bladder > urethra > exterior

Question 4

structures of adult kidney

Answer 4

adrenal, cortex, medulla, collecting system, ureter

Question 5

urogenital system comes from what embryonic tissue layer

Answer 5

intermediate mesoderm

Question 6

urogenital ridges

Answer 6

derived from intermediate mesoderm

> nephrogenic cord (urinary) and genital/gonadal ridge (genital)

Question 7

embryological kidney evolution

Answer 7

pronephros > mesonephros > metanephros

Question 8

pronephros location, timing

Answer 8

4th embryonic week, cervical nephrotomes, transitory & nonfunctional

Question 9

mesonephros timing, structures

Answer 9

late in 4th week; nephrotomes > glomeruli, mesonephric tubules, mesonephric ducts; degenerate end of 1st trimester except some adult male derivatives

Question 10

how bowman’s capsule created

Answer 10

capillaries meet at end of mesonephric tubules

Question 11

mesonephric tubule shape, function, structures

Answer 11

straight > tortuous
filtration
glomerulus at distal end

Question 12

definitive kidneys

Answer 12

metanephros

Question 13

metanephros timing

Answer 13

week 5: develop
week 9: function
week 12: most amniotic fluid is urine

Question 14

metanephric diverticulum

Answer 14

distal outpouching of metanephric duct = ureteric bud, enters cloaca
> ureters, renal pelvis, calices, collecting tubules (aka collecting system of kidneys)

Question 15

ureteric bud forms

Answer 15

collecting system of ureter

Question 16

blastema is from/forms

Answer 16

metanephric mass of intermediate mesoderm > nephrons

Question 17

reciprocal induction

Answer 17

ureteric bud (metanephric diverticulum) and blastema (metanephric mass of intermediate mesoderm) induce each other’s formation

Question 18

ureteric bud branches

Answer 18

1-4: major calices
4-8: minor calices
4 degrees of branching each into collecting ducts

Question 19

nephron components

Answer 19

corpuscle (bowman’s capsule, glomerulus), PCT, loop of henle, DCT

Question 20

fetus has all nephrons for adult by when

Answer 20

32 weeks

Question 21

how nephron forms

Answer 21

blastema > nephric vesicle
nephric vesicle elongates, twists, into metanephric tubules
distal end of metanephric tubule invaginates by glomerular capillaries > all structures

Question 22

fetal kidney shape

Answer 22

lobular

Question 23

when glomerular filtration begins

Answer 23

week 9; increases after birth

Question 24

size of adrenal gland in fetal kidney/adult kidney

Answer 24

fetus: same as kidney
adult: smaller than kidney

Question 25

kidney’s “movement”

Answer 25

originally in pelvis, next to bladder > caudal portion grows, “ascend” to abdomen until adrenals

Question 26

rotation of kidney hilum

Answer 26

90 degrees medially during “migration” so kidneys face each other

Question 27

blood supply to kidneys over time

Answer 27

common iliacs (early) > renal arteries (adult)

Question 28

urorectal septum made from

Answer 28

intermediate mesoderm that grows into cloaca simultaneous w/ kidney

Question 29

urorectal septum divides

Answer 29

ventral bladder, dorsal rectum

Question 30

urogenital sinus parts

Answer 30

1. vesical-bladder
2. pelvic-urethra
3. phallic-genital tubercle

Question 31

layers of urinary bladder

Answer 31

sphlancnic mesoderm (outer), endoderm (epithelium)

Question 32

trigon of bladder

Answer 32

where ureters enter bladder (proximally), where urethra exits (distally)

Question 33

bladder location (children/adult)

Answer 33

abdominal, pelvic

Question 34

kidney stage ureters are from

Answer 34

metanephros

Question 35

allatois

Answer 35

initially, continuous with bladder’s vesicle protion > constricts, becomes urachus (ligament) > median umbilical ligament (vestigial) in adults

Question 36

female urethra derivation

Answer 36

urogenital sinus endoderm, CT/smooth muscle from splanchnic mesoderm

Question 37

male urethra derivation

Answer 37

proximal-urogenital sinus, distal-epithelial ingrowth from penis, CT/smooth muscle from splanchnic mesoderm

Question 38

2 parts of adrenal glands, their derivations

Answer 38

mesoderm > cortex

neural crest cells > medulla

Question 39

adrenal gland fetal cortex in adult (3 layers)

Answer 39

3 layers- zona glomerulosa, zona fasiculata, zona reticularis

Question 40

hormones medulla produces

Answer 40

epinephrine, norepinephrine - fight/flight

Question 41

hormones cortex produces

Answer 41

zona glomerulosa- mineralocorticoids (salt/fluid regulation)
zona fasiculata- carb, protein, fat, cortisol metabolism (sugar)
zona reticularis- sex steroid precursors (sex)

Question 42

renal agenesis

Answer 42

no blastema > no kidney develops > no amniotic fluid > bilateral renal agenesis, cannot see fetus on U/S, lethal anomaly d/t pulmonary hypoplasia

Question 43

potter sequence

Answer 43

clinical correlate, no blastema > fetal muscles/limbs fixed, face smashed in, feet clubbed

Question 44

“prune belly” syndrome

Answer 44

in males, if no cnxn between endoermal part of urethra-epithelial ingrowth from outside, tissue not obliterated > valve-like structures form, keep urine from coming out > bladder fills til huge > amniotic fluid trapped in, lethal anomaly