Development Flashcards
What fuses in the midline to create a single heart tube?
Endocardial tube
What do endocardial heart tubes begin as? How many endocardial tubes develop?
Angioblastic cords; 4
What adult structures are formed by the endocardial heart tubes?
The medial two become dorsal aorta; lateral tubes fuse to form the cords that create the primitive heart
What is the venous end that anchors the heart tube caudally?
Sinus venosus
What is the flow of blood through the sinus venosus into the primitive heart tube?
->primitive atrium–>atrioventricular canal–> primitive ventricle–>bulbus cordis–> truncus arteriosus–>aortic sac–> dorsal aortic arches
What structures arise from the truncus arteriosus?
Aorta, pulmonary trunk, aorticopulmonary septum
What forms from the bulbus cordis?
Smooth part of the right ventricle (conus arteriosus) and the smooth part of the left ventricle (aortic vestibule)
From the primitive ventricle arise?
The muscular portion of both ventricles?
What develops from the primitive atrium?
The muscular portion of each atria
From what does the sinus venarum develop?
The right horn of the sinus venosus
From what does the sinus venosus receive venous blood?
Common cardinal veins, umbilical veins, vitelline veins?
What is formed by the union of the anterior and posterior cardinal veins?
Common cardinal veins
What brings unoxygenated blood back from the embryo?
Common cardinal veins
Where does the umbilical vein drain?
The placenta
What kind of blood is contained in the umbilical veins?
Highly oxygenated blood
What area do the vitelline veins drain?
The yolk sac
Of what is the pericardial sac a subdivision?
The intraembryonic coelom
The formation of which structures divides the single atrioventricular canal into right and left atrioventricular canals?
Endocardial cushions
What is the initial septum formed in the development of the interatrial septum?
Septum premum
What forms from the several perforations created in the septum premum as it grows?
Foramen secundum
What is the second septum to grow, which is immediately to the right of the septum primum?
Septum secundum
What forms from the opening of the septum secundum?
Foramen ovale
What will give rise to the coronary sinus?
The left horn of the sinus venous
From what does the sinus venarum develop?
Right horn of the sinus venosus?
What vessels arise from the right horn of the sinus venosus?
Oblique vein of left atrium, middle, small, and great cardiac vv.
From the umbilical vein where does blood go?
Half through ductus venosus into inferior vena cava and half into the liver and through the liver sinus and then into IVC via heptaic veins
Into what does the Inferior Vena Cava drain?
Right attrium
What is the flow of blood from IV through the fetal heart?
Into right atrium–>foramen ovale–>left attrium–>left ventricle–>ascending aorta
What is the flow of blood from the superior vena cava through the heart?
Right atrium–>right ventricle–>pulmonary trunk–>ductus arteriosus–>descending aorta
What does the proximal part of the umbilical arteries become?
Superior vesicle arteries to bladder
What does the distal parts of umbilical arteries become?
median umbilical folds
What changes occur in the fetal circulation after birth?
Increased pulmonary blood flow, thinning of pulmonary artery walls, closure of foramen ovale, ductus venosus–> ligamentum venosum, ductus arteriosus–> ligamentum arteriosum,
What causes constriction of the ductus arteriosus?
Increased oxygenation and secretion of bradykinin by lungs
What four things will occur with tetralogy of Fallot? What is the most obvious sign?
Pulmonary stenosis; right ventricular hypertrophy; ventricular septal defect; dextroposition of aorta (overriding aorta)
What is the most common single cause of cyanotic heart disease in newborns?
Transposition of Great Arteries
What is the anatomical basis of transposition of great arteries?
Improper formation of aorticopulmonary septum
What develops from the first aortic arch?
Maxillary artery (contributes to external carotid)
What develops from the 2nd aortic arch?
Stapedial aa.
What develops from the 3rd aortic arch?
Common carotid aa.
What develops from the 4th aortic arch?
Left–> (part of) arch of aorta
Right–> Right subclavian a.
What develops from the 6th aortic arch?
Left proximal–> Left pulmonary a.
Left distal–> ductus arteriosus
Right–> right pulmonary artery
What gives rise to the larynx and the trachea?
Laryngotracheal diverticulum
The larygotracheal diverticulum continues to grow outward to become? What does this structure subdivide into?
Lung bud; bronchial buds
What separates the laryngotracheal tube into the trachea and esophagus?
Tracheoesophageal septum
What is esophageal atresia?
Esophagus ends in a blind pouch
What is a esophageal fistula?
Incomplete division of the crainal part of the foregut into the respiratory and esophageal part
What are the stages of respiratory development?
Pseudoglandular, Canalicular, Terminal sac, Alveolar periods
What is the earliest stage of respiratory development at which an infant could be born and breathe?
Canalicular period
What period takes place after birth?
Alveolar periods
In what period is the blood-air barrier established?
Terminal sac period
Respiratory distress syndrome is due to what?
Surfactant deficiency
The lateral mesoderm splits into what two layers?
Somatic and splanchnic mesoderm
What is the space between the somatic and splanchnic mesoderm?
Intraembryonic coelom
From what tissue layer are the parietal layer of serous membranes developed?
Somatic mesoderm
From what tissue layer are the visceral layer of serous membranes developed?
Splanchnic mesoderm
What makes up a somatopleure?
Superficial ectoderm + somatic mesoderm
What makes up a splanchnopleure?
Endoderm + splanchnic mesoderm
What are the three well-defined coelomic cavities at 4 weeks of development?
Pericardial cavity, Pericarioperitoneal canals, Peritoneal cavity
What three sets of partitions are present in the body cavity at 4 weeks of development?
Septum transversum, pleuro-pericardial membranes, pleuro-peritoneal membranes
What four structures contribute to the development of the diaphragm?
Septum transversum, pleuroperitoneal membranes, dorsal mesentery of the esophagus, body wall
What gives rise to the central tendon of the diaphragm?
Septum transversum
What gives rise to the left and right crura?
Dorsal mesentery of the esophagus
What is the developmental cause of congenital diaphragmatic hernias?
Defective formation and/or fusion of pleuroperitoneal membranes
Where do congenital diaphragmatic hernias typically occur?
Posterolateral- Foramen of Bochdalek
Where is there continuity between intra and extra-embryonic coelom?
Umbilical cord
What is derived from the foregut?
Everything supplied by celiac a.
What is derived from the midgut?
Everything supplied by superior mesenteric a.
What is derived from the hindgut?
Inferior mesenteric a. supplied organs
What condition can result from a short esophagus?
Hiatal hernia
What forms the anterior vagal trunk?
Left vagus n.
What forms the posterior vagal trunk?
Right vagus n.
What structures (3) persist from the ventral mesentery?
Lesser omentum, Falciform ligament, hepatogastric ligament; hepatoduidenal ligament
What structures (10) are derived from the dorsal mesentery
Greater omentum, gastrosplenic ligament, gastrophrenic ligament, gastrocolic ligament, lienorenal ligament, mesentery proper, tranverse mesocolon, mesoappendix, phrenicocolic ligament, mesocecum
Through what does the lesser peritoneal sac communicate with the greater peritoneal sac
Omental foramen/ Foramen of Winslow/Epiploic foramen
Within the portal triad, which structure is the most posterior?
Hepatic portal vein
Within the portal triad, which structure is anterior and to the left?
proper hepatic artery
What is just posterior to the portal triad?
Inferior vena cava
From what tissues does the duodenum develop?
Caudal foregut and rostral midgut
The rotation of the duodenum causes the common bile duct to switch its ______ position to _______ positions?
Ventral; posterior
In what parts of the duodenum does stenosis more commonly occur?
3 & 4
In what parts of the duodenum does atresia more commonly occur?
2 & 3
The liver bud is divided into a cranial and caudal part. What structures do these parts develop into?
Cranial- Liver; caudal- gallbladder
Which bud of the pancreas rotates 90 degrees?
Ventral pancreatic bud
What is annular pancreas?
One of the ventral pancreatic buds rotates normally but the other does not resulting in the fusion of the buds around the 2nd part of duodenum
From what does the main pancreatic duct develop? The accessory duct?
The duct of the ventral pancreatic bud and the distal part of the dorsal pancreatic bud; proximal part of dorsal pancreatic duct
What are the three stages of movement in the development of the midgut?
Herniation, Return, Fixation
What is the total degree of rotation accomplished by the gut loop?
270 CCW
What structure is developed from a swelling on the distal limb at its junction with the proximal limb?
Cecum
What are the secondary retroperitoneal organs?
ascending and descending colon, 2-4 duodenum
How many layers makes up the omentum?
4
What results from incomplete obliteration of vitelline duct?
Ileal (Meckel’s) Diverticula
What is an omphalocele?
When intestinal loop fails to return from the umbilical cord to the abdominal cavity
What is Gastroschisis?
Gut herniates out (usually superior and to the right of umbilicus) due to failure of the lateral body folds to fuse completely when forming anterior abdominal wall
The cloaca receive input from what two things?
The hindgut and the allantois
The cloaca extends down and makes contact with what structure to form the cloacal membrane?
Proctodeum
Into what does the urorectal septum divide the cloaca?
Urogenital sinus and anorectal canal
What is the point of fusion between the urorectal septum and cloacal membrane?
Perineal body
