L10.1 Regulation of Kidney Development Flashcards
1
Q
3 pairs of organs during kidney development
A
From intermediate mesoderm
- Pronephroi (regress)
- Mesonephroi (may regress)
- Metanephroi
- Pronephros DOESN’T become mesonephros which DOESN’T become the metanephros
- But 1 has to occur before the other one
2
Q
Pronephros
A
- Transient organ in mammals
- Important in amphibians and fish BUT NOT humans
- 1 glomus draining into pronephric tubules → into pronephric duct
3
Q
Mesonephros
A
- Pronephric duct → wolffian duct → induce mesonephros → renal vesicles → proximal tubule
- Have multiple glomeruli and mesonephric tubules → draining into mesonephric duct
- Around 40 nephros in humans
- Most prominent organ region in early gestation
- Mesonephric tubules form the efferent tubules of testis (male)
4
Q
Metanephros
A
- Begins at ~day 30 in human and finishes just before birth
- Co-exists with mesonephros
- ~1m nephrons in humans
- Very Variable (even populations/ethnicity plays a role)
- Can survive fetal without, but not post-natal
5
Q
How is the metanephros developed
A
- specification of metanephric blastema
- From this point forms the glomerulus and tubules
6
Q
Urerteric branching (UB) and morphogenesis
A
- Outgrowth at the caudal end of Wolffian Duct
- Invade metanephric mesechyme (MM) → induce UB
- Reciprocal induction b/w UB and MM
- Also forms collecting ducts/calyces/renal pelvis
- Part of UB that does not enter MM forms ureter
7
Q
Nephrogenesis
A
- UB induce MM to condense → forms a cap mesenchyme → pretubular aggregate → undergo MET → renal vesicle
8
Q
What does the renal vesicle develop into?
A
- Comma shaped → then S shaped
- Upper → distal convoluted tubule
- Central → PCT, LoH, distal straight tubule
- Lower → Renal corpuscle
9
Q
Arcade formation
A
- Tip branching only until week 15
- After wk 15 → nephrons form on one arcade
- 7-10 nephrons form on one arcade
- Tip forms 1 nephron → connects to collecting duct
- 2nd nephron induced by same tip → shift 1st and connects
- After 20 wks → further nephrons form along length of collecting duct
- 7-10 nephrons form on one arcade
- Allows more nephrons to be formed
10
Q
Renal Nerve development
A
- Adrenergic N from 20wks in humans
- Formed in cortex and medulla
- Reaches adult lvls in cortex by 28wks
- Decreases in later gestation (more important in gestation)
- Regulate renin secretion in fetus → regulate vasodilation
- Formed in cortex and medulla
11
Q
Vascular development
A
- Capillaries detected around UB after it enters MM
- 8-10wks → vessels around S shaped bodies
- Vasculogenesis or angiogenesis? (debate)
12
Q
Development of kidney function in utero
A
- Urine excreted into amniotic fluid but can’t concentrate urine like adult
- Produces hormones (renin/erythropoietin)
- Contributes to amniotic fluid → important for gestation (e.g. dev of lungs)
13
Q
Abnormalities of renal development
A
- Bilateral renal agensis (Potters syndrome)
- Don’t dev kidneys → don’t survive postnatally
- Congenital abnormalities of kidney and urinary tract (CAKUT)
- Hydronephrosis
- Restriction of ureter
- Polycystic kidney disease
- Maternal drug use → leading to other deficits
14
Q
Potter’s syndrome
A
- No urine produced in utero → lacks amniotic fluid → causes gross abnormalities
- Death post natally due to lung insufficiency
- Treatment → complete dialasis through peritoneum
- If is a Unilateral agensis→ able to live without much complications → but more easily develop renal disease
15
Q
CAKUT
A
- 1/3 of abnormalities (genetic abnormalities underlie many cases)
