Block 3 Development Flashcards
What are the components of the somatopleure?
The splanchnopleure?
Somatopleure = Superficial ectoderm + somatic mesoderm
Splanchnopleure = Endoderm + splanchnic mesoderm
The somatic layer of mesoderm forms the _____ layer of pleura, pericardium & peritoneum while the splanchnic layer forms the _____ layer.
Somatic - parietal (GSA)
Splanchnic - visceral (GVA)
What are the three coelomic/body cavities present after 4 weeks of development
Pericardial cavity
Peritoneal cavity
Pericardioperitoneal canals
The pericardial and peritoneal cavities are separates by the _____
Septum transversum
The pleura and pericardium are separated by the _____
Pleuro-pericardial membranes
The central tendon of the diaphragm arises from the _____
Septum transversum
The muscular component of the dorsal mesentery of the esophagus forms what part of the diaphragm?
The crura on either side of the aortic hiatus
The peripheral portions of the diaphragm are formed from _____
The abdominal (body wall)
What positionis the diaphragm at at 4 weeks? 6 weeks? 8 weeks?
4th week: Opposite 3rd, 4th, 5th cervical somites
6th week: Level of thoracic vertebrae
8th week: Level of L1
A congenital diaphragmatic hernia, forming a Foramen of Bochdalek, is a posterolateral defect resulting from the failure of _____.
Pleuroperitoneal membrane fusion
A severe consequence of a congenital diaphragmatic hernia is _____
Pulmonary hypoplasia (Not enough room for lung to develop properly)
Also causes mediastainal deviation (displacement of organs away from the hernia)
_____ is a condition where the esophagus ends as a blind tube. It results in polyhydramnios.
Esophageal atresia
_____ is a condition that results in a connection between the esophagus and trachea. This results in aspiration of fluid, and air in the stomach.
Esophageal fistula
A congenital hiatal hernia is the result of an _____. The esophagus will herniate through its hiatus.
Esophagus that is too short
The stomach forms from a dilation in the _____ in the 4th week.
Caudal part of foregut
The developing stomach is suspended from the posterior abdominal wall by _____
Dorsal mesentery (Dorsomesogastrum)
The dorsal part of the developing stomach will form the _____, while the ventral part will form the _____
Greater curvature
Lesser curvature
The 90 degree rotation of the stomach in development has what consequences?
Hint: there are four
Dorsal border moves to left side
Ventral border moves to right side
Left vagus nerve becomes anterior vagal trunk
Right vagus nerve becomes posterior vagal trunk
The dorsal mesentery of the stomach goes on to form the _____
Greater omentum
_____ is the result of a hypertrophy of the pyloric sphincter. What giveaway symptom would be present in this condition?
Hypertrophic pyloric stenosis
Projectile non-bilious vomiting
What gives the duodenum its characteristic C-shape?
90 degree rotation to the right in development
The first part of the duodenum is _____ while the 2nd, 3rd, and 4th part is _____
1st part - intraperitoneal
2nd, 3rd & 4th part - Secondary retroperitoneal
Duodenal stenosis occurs when _____, while duodenal atresia occurs when _____
Stenosis - Duodenum doesn’t recanalize enough
Atresia - Duodenum doesn’t recanalize at all
What kind of vomiting would you expect in duodenal stenosis or atresia?
Bilious vomiting (obstruction is distal to entrance of common bile duct)
The liver develops from what embryonic structure?
Hepatic diverticulum
The hepatic diverticulum is a ventral outgrowth of _____, will eventually form _____
Endoderm at caudal end of foregut
Hepatic cords
The larger cranial portion of the hepatic diverticulum will form the _____, while the smaller caudal portion will form the _____
Cranial > Liver
Caudal - Gallbladder
The stalk of the hepatic diverticulum will form the _____ and _____
Cystic duct
Common bile duct
The majority of the UG system develops from _____
Intermediate mesoderm (of Swartz!)
_____ arise from intermediate mesoderm and are longitudinal elevations along the dorsal body wall.
Nephrogenic cords
The _____ is the initial stage of the kidney. It forms and disappears during the 4th week.
Pronephros
The _____ is the second stage of the kidney. It is composed of mesonephric ducts and tubules.
Mesonephros
Two parts of the mesonephros?
Mesonephric ducts and tubules
The mesonephros empties into what embryologic structure?
Cloaca
The _____ is a definitive kidney composed of two parts: the metanephric diverticulum and the metanephrogenic blastema. It is the third and last stage of the kidney.
Metanephros
Two parts of the metanephros?
Metanephric diverticulum (ureteric bud) - “Collecting system”
Metanephrogenic blastema (metanephric mass) - “Excretory system”
The nephron is composed of the renal corpuscle and convoluted tubules. These two parts arise from what part of the metanephros?
Metanephric blastema
The uriniferous tubule is composed of a nephron and collecting tubules. From what part of the metanephros do these two structures arise?
Nephron - Metanephric blastema
Collecting tubules - Metanephric diverticulum
The urorectal septum divides the cloaca into the _____ and _____
UG sinus
Anorectal canal
As the urorectal septum continues to grow towards the cloacal membrane, is forms what three parts of the UG sinus?
Vesical part - Forms urinary bladder
Pelvic part - Prostatic & membranous urethra in male, entire urethra in female
Phallic part - Most of penile part of urethra in male (tip formed by invagination of ectoderm)
_____ occurs when the ureteric bud fails to develop
Renal agenesis
Unilateral involves compensatory hypertrophy of other kidney
Bilateral results in oligohydramnios, is incompatible with life
_____ results when the ureteric bud splits and develops two duct systems
Double ureters
A _____ occurs when the inferior poles of the kidneys fuse
Horseshoe kidney
The failure of mesoderm to develop between ectoderm and endoderm in the lower abdominal wall causes a failure of the abdominal wall to fuse. This is of what consequence to the bladder? What is this condition known as?
Anterior wall of bladder degenerates
Exstrophy of the bladder
The adrenal cortex is derived from _____, while the adrenal medulla is derived from _____
Cortex - Mesoderm (mesenchyme)
Medulla - Ectoderm (NCC)
What are the sole source of sex cells?
Primordial germ cells
Primodial germ cells migrate to the _____. What would result if this migration were impeded?
Genital ridges
Would result in infertility
The gonads are derived from what three sources?
Mesothelium (mesodermal epithelium) - lining posterior abdominal wall
Mesenchyme
Primordial germ cells
In order for the medulla of the indifferent gonads to become testes, what two things must be present? What happens to the cortex of the indifferent gonads if these two things are present?
XY sex chromosome complement
Testis determining factor (TDF)
The cortex will regress (Male development)
In male gonadal development, the primary sex cords will become _____. These will eventually go deeper and develop a coiled network called the _____
Seminiferous (Testicular/Medullary) Cords
Rete testis
The seminiferous tubule is made up of what two cell types? What do these cells secrete? What does their secretion accomplish?
Primordial germ cells & Sertoli cells
They secrete anti-mullerian hormone, which destroys the paramesonephric ducts.
Interstitial/Leydig cells secrete _____ and will form from _____
Testosterone
Mesenchyme
What structure separates the testis cords from the superficial epithelium?
Tunica albuginea
