Development and Congenital Abnormalities of the Urinary System Flashcards
What are the hereditary disorders of tubule function?
- Bartter’s syndrome (Type 1)
- Gitelman’s syndrome
- Liddle’s syndrome
- Pseudohypoaldosteronism
- Inactivating Mutations of Aquaporins
Describe Bartter’s syndrome (Type 1)
- Impaired SLC12A2 transporter
- In loop of Henle
- Na+, K+, Cl- to make hypertonic area of medulla
What are the effects of Bartter’s syndrome (Type 1)?
Loss of Na+ K+, much
H2O; hypercalciuria
-Same as loop diuretics
Describe Gitelman’s syndrome
- Impaired SLC12A3
- Sodium and chloride uptake channel of distal tubule
What are the effects of Gitelman’s syndrome?
Loss of Na+, K+, modest H2O
-Like thiazide diuretics
Describe Liddle’s syndrome
-Hyperactive ASC (=ENaC)
What are the effects of Liddle’s syndrome?
Volume expansion
(body) , hypertension
- Opposite of diuretics
- Can still treat with amiloride
Describe Pseudohypoaldosteronism
- Inactive ASC (=ENaC)
- Aldosterone usually transcribes ASC
What are the effects of Pseudohypoaldosteronism?
Na+ loss, K+ retention, high aldosterone (trying to correct problem)
-Like amiloride
What are the effects of Inactivating Mutations of Aquaporins?
(In collecting duct) Nephrogenic Diabetes insipidus (polyuria, polydipsia) =more urine flow Insipidus= dilute
What are the problems outside the kidney?
- Addison’s disease
- Psychogenic polydipsia
Describe Addison’s disease
-Destruction of adrenal glands
=Loss of Na+, hyperK+, hypovolaemia
=Less aldosterone- spironolactone
Describe Psychogenic polydipsia
-Continuous thirst
=Whole body hypoosmolarity (diluting)
Describe simple embryonic kidneys (pronephros)
-Leaky capillaries
-Ciliated funnel that drags fluid from capillaries
-Proximal tubule
-Drains into long pipe (nephric Wolffian duct) into cloaca (common exit with gut)
=No true glomerulus
Describe the mesonephros
- Second kidney formed
- Both attached to nephric duct
- More advanced nephrons
- Leaky capillaries and ciliated funnel budded off
- More convoluted tubules
- Develop next to gonads
- Males= some tubules co-opted by testis
What do the parts of the mesonephros (temporary kidney) become in the adult male testis?
- Tubules= epididymis
- Nephric duct= vas deferens
Describe the metanephros
-What will become our kidneys
-Specialised mesenchyme
-Branch from cloaca that grows into metanephrogenic mesenchyme= urine collecting duct system
=Induces cells of mesenchyme to make stem cell populations that will both maintain themselves and make epithelia that make nephrons
(this is why the nephron stops at DCT)
Describe the development of the bladder
- Starts to form from where the nephric duct and the ureter bud diverge as they come into the cloaca
- Part of allantois
- Nephric duct and ureter flow into bladder, separate at junction
Describe the development of the prostate
- Prostate glands at junction
- Below bladder
What are the components of semen and what glands make them?
-Testis – sperm
• Prostate – citric acid (energy and buffering), enzymes, acidic
proteins
• Seminal Vesicle – fructose (energy), basic proteins (various modulators of immune response)
Describe the timing of release during ejaculation
- Prostate
- Epididymis
- Seminal vesicles
Describe male development of nephric and Mullerian ducts
- Indifferent gonad develops testis cords
- Testis cords connect to some mesonephric tubules (->epididymis)
- Mullerian duct regresses
- Distal nephric duct sprouts seminal vesicles – the part of the nephric duct distal to this is the ejaculatory duct
- Urethra sprouts prostate and bulbourethral glands.
Describe female development of nephric and Mullerian ducts
• Indifferent gonad develops into an ovary
• Upper Mullerian ducts
become fallopian tubes
• Mullerian ducts converge & fuse to become the uterovaginal canal
• Nephric ducts and mesonephros degenerates
• Uterovaginal canal forms uterus and upper part of vagina. (Lower part from urogenital sinus, part of cloaca)
Describe the development of the external genitalia
-In undifferentiated stage
=phallus ending in gland, urogenital folds and urogenital groove between
-In females: folds= labio-scrotal swellings= labia, phallus= clitoris
-In males= more growth of phallus to become penis, labio-scrotal swellings fuse along midline forming scar called a raphe, urethra moves from original opening site to end of penis
Contrast the male and female urethras
- Male: urethra runs along penis and opens at end
- Female: urethra ends within vulva and does not run to end of clitoris
What is Renal Agenesis?
• Bilateral – No kidneys form. Rare; fatal after birth.
Lack of amniotic fluid causes Potter’s Facies.
• Unilateral – One kidney missing. Common
(1/500). Often no clinical implications unless
some bright surgeon removes the working one.
Describe what Potter’s Facies look like
-Flat nose
-Flat chin
-Ears against head
=Normally amniotic fluid provides bubble-like cushion (most foetal urine)
Describe polycystic kidney disease
-Most common genetic disease
=Very large
=Cysts grow and destroy normal kidney underneath
=Variability in onset and mechanism
Describe a supernumerary ureter
- Nephric duct gives rise to two branches
- Usually no problem if unite and go into bladder properly
- Or can join beneath the bladder so is not stored- constant urine flow in urethra, more risk of infections tracking into kidney as no bladder
Describe Pelvic Kidney
- Misplaced kidney, remains in pelvic region
- Male= little consequence
- Problem with pregnant females
- If both kidneys in pelvis= fuse and jammed by blood vessels (horseshoe)
What are the congenital abnormalities of the cloaca (common exit in embryo)?
Failure of correct positioning of Rathke and Tourneaux (fold of tissue)
folds results in;
• Rectovaginal fistula (infection risk)
• Rectoprostatic fistula
• Rectoclocal canal (rectum, vagina and urethra unite
inside body).
-In males, incomplete migration of the urethral groove from the base of the penis to its tip results in hypospadias
