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56 Cards in this Set
- Front
- Back
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What does the Bladder develop from?
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Subdivision of the cloaca
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What is the cloaca?
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The terminal end of the hindgut; a common area for the opening of the newly formed GI and UG ducts.
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How does the CLOACA get subdivided to separate the UG and GI systems?
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By formation of the Urorectal Septum.
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What closes the Cloacal membrane off from the exterior? Where does it extend between?
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The Cloacal Membrane extending from the Allantoic stalk to tailbud.
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What does the Urorectal Septum subdivide the cloaca into?
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1. Primary UG sinus (ventral)
2. Anorectal Canal (dorsal) |
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What IS the Urorectal Septum?
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A wedge of mesenchyme between the allantois and hindgut
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What happens to the Urorectal septum?
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It grows ventrally, fuses with the cloacal membrane to form the Perineal Body
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How does an exterior opening in the UG duct develop?
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By apoptosis of the Cloacal membrane - probly due to pressure from urine.
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What happens to the Primary UG Sinus?
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Gets subdivided into:
-VesicoUrethral Canal (VU) -Definitive UG Sinus |
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What determines the point of Primary UG Sinus subdivision?
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Point of entry of the mesonephric duct
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What develops from the VU canal?
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-Bladder
-Part of urethra |
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What is the apical part of the VU canal continuous with, and what does it eventually form?
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-Contin. w/ Allantois
-Becomes fibrous Urachus (remn) |
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In the Bladder what derives the:
-Epithelial lining -Walls |
Epithelium = endodermal tissue
Walls = Splanchnic mesoderm |
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What happens to the Mesonephric duct distal to the Ureteric bud?
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Forms the TRIGONE of the bladder as it is absorbed into the posterior bladder wall.
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What is the fate of the Mesonephric ducts in
-Females -Males |
Females: atrophy
Males: vas deferens - allows it to dump into the bladder. |
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What happens to the bladder after birth?
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Descends, drags urachus with it
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What part of the urethra is formed from the VU canal in Males?
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Only the proximal portion of the prostatic urethra.
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What part of the urethra is formed from the VU canal in females?
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Most of it
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What is the caudal (lower) part of the UG sinus called (after separation from VU canal)?
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Definitive UG Sinus - below the entry point of Mesonephric duct.
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What develops from the Definitive UG Sinus?
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2 subdivisions:
-Pelvic part (proximal) -Phallic part (distal) |
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Fate of Pelvic part of Definitive UG Sinus in MALES:
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-Distal prostatic urethra
-Membranous urethra |
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Fate of Pelvic part of Definitive UG Sinus in FEMALES:
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Lower 1/2 of vagina
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Fate of Phallic part of Definitive UG Sinus in MALES:
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Penile urethra
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Fate of Phallic part of Definitive UG Sinus in FEMALES:
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Vestibule
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2 Types of Anomalies associated w/ Urinary Bladder development:
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1. Urachal anomalies
2. Exstrophy of the Bladder |
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What are 3 Urachal anomalies?
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1. Urachal cysts
2. Vesical diverticulum 3. Vesico-umbilical Fistula |
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What are Urachal cysts derived from?
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Epithelial lining of the urachus
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What is a Vesical Diverticulum?
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A communication of the bladder and a urachus remnant.
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What is a Vesico-umbilical fistula?
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Patent Urachus - communication of the bladder with the umbilicus - can cause presence of urine at the umbilicus.
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What sex is Exstrophy of the bladder more common in?
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Males - 3.5 x more common!
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What IS Exstrophy?
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Eversion of a hollow organ, so that its lining is exposed to the surface.
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What is the cause of Bladder Exstrophy?
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Ventral Body wall Defect - interferes with migration of muscle progenitors.
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What are the 3 key features of Exstrophy of the Bladder?
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1. Epispadius
2. UG/Skeletal anomalies 3. Exposed lining of posterior bladder to ventral body surface. |
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What is a much more severe form of Extrophy down there?
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Exstrophy of Cloaca - includes both UG and GI anomalies
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What is Epispadius?
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Dorsal opening of the penile urethra
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What 2 anomalies are associated with urethra development?
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1. Agenesis/atresia
2. Posterior urethral valves |
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What sex is urethral agenesis more commonly associated with?
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Males
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What syndrome is urethral agenesis associated with?
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Prune belly - due to atresia of abdominal wall muscles.
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What is the important thing to remember about Posterior Urethral Valves?
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-ONLY in males
-Tissue folds of posterior urethra mucosa act like valves and obstruct it. |
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What makes Posterior urethral valves significant?
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Most common cause of uropathy leading to renal FAILURE in children.
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What is the ORIGIN of the Adrenal Cortex?
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Coelomic Epithelial cells & possibly cells from mesonephros.
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How does the fetal adrenal cortex form?
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Chords of epithelial cells extend into underlying UG Ridge
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How does the Fetal adrenal cortex compare to adult?
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20X larger; composes 80% of total adrenal gland in fetus.
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What stimulates development of the fetal adrenal cortex?
-early -later |
Early: hCG
Later: ACTH |
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When does the fetal adrenal cortex begin to shrink?
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At birth; completed by 6 mo-1yr
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What is inactive in the fetal cortex, and what is the consequence?
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3b-hydroxysteroid dehydrogenase
-Can't make progesterone or androstenedione. |
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What is the DEFINITIVE adrenal cortex?
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At birth, a thin layer external to the fetal cortex.
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What will the definitive cortex develop into?
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3 zones - glomerulosa, etc..
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What is "materno-feto-placental unit"?
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Cooperation of mother/fetus to increase estrogen production by the placenta - makes gluco- and mineralcorticoids.
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What does the Adrenal MEDULLA derive from?
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Neural Crest cells - invade the cortex and move centrally.
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What 3 parts of the medulla develop from these neural crest cells?
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-Chromaffin tissue
-Neurons -Glandular cells |
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What are 2 forms of abnormal adrenal development?
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1. Congenital Adrenal Hyperplasia
2. Adrenal hypoplasia |
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What is the main feature of CAH?
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Genetic defic in hydroxylase enzyme production
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What results from CAH?
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-Increased ACTH
-Increased androgens -Adrenal hyperplasia |
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What happens to CAH Patients if
-Male? -Female? |
Male: precocious development of external genitalia
Female: masculinized external genitalia |
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What is Adrenal Hypoplasia associated with, & what results?
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-Assoc w/ Anencephaly
-No pituitary - no ACTH |
