Clinical Embryology Flashcards by Austin Flick

What is Ectopia cordis and what causes it

condition where heart is partly or completely exposed usually on thoracic surface

results usually from failure of lateral folds to fuse in that region

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What is Gastroschisis and what causes it

usually on right side, allows abdominal viscera to protrude into amniotic cavity

uncommon defect in ventral abdominal wall resulting from incomplete closure of lateral folds

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What is pulmonary hypoplasia and what is the major cause of it

Lung underdevelopment

Congenital diaphragmatic hernia

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What is a congenital diaphragmatic hernia and what usually causes it

Posteriolateral defects in diaphragm allowing herniation of abdominal viscera into thoracic cavity

failure of pleruoperitoneal membrane to fuse with septum transversum and or dorsal mesentery of esophagus

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on which side is a congeneital diaphragmatic hernia almost always found

Left

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The mesodermal structure lying caudal to the pericardial cavity after folding of the head region is the
septum transversum
primitive streak
developing heart
oropharyngeal membrane
notochord

septum transversum

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A newborn infant has a congenital diaphragmatic hernia, this results from defective formation of which structures
Costodiaphragmatic recess
dorsal mesentery of the esophagus
lateral body wall
pleuroperitoneal membrane
septum transversum

Pleuroperitoneal membrane

failure to fuse with dorsal mesentery of esophagus and septum transversum

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What is the most common abnormality of the lower respiratory system and what causes it

Tracheoesophageal fistual

iincomplete separation of the esophagus and trachea

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What are tracheoesophageal fistulas usually associated with

esophageal atresia

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What symptoms come with tracheoesophageal fistulas and esophageal atresia

polyhydramnios: excess amniotic fluid during pregnancy (not oligohydraminos which is too little)

excess salivation

regurgitation after feeding

abdominal distention after crying

inflammation of lungs

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Why might you get inflammation of the lungs with tracheoesophageal fistulas and esophageal atresia

reflux of stomach contents into the lungs

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Which of the following is often associated with a tracheoesophageal fistulas and esophageal atresia
Unilateral agenesis of the lung
Laryngeal atresia
Unilateral pulmonary agenesis
polyhydramnios during pregnancy
congenital lung cysts

Polyhydramnios during pregnancy

because fetus is unable to swallow amniotic fluid which then accumulates because it is unable to pass to the fetal stomach and intestines for absorption

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What is the first indication of lower respiratory tract development in the human embryo
Bronchial bud
laryngotracheal groove
primary bronchus
bronchopulmonary segment
lung bud

Laryngotracheal groove

forms as an outgrowth from primitive pharyngeal floor during 4th week

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Why would polyhydramnios occur during pregnancy with tracheoesophageal fistulas and esophageal atresia?

because fetus is unable to swallow amniotic fluid which then accumulates because it is unable to pass to the fetal stomach and intestines for absorption

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Atrial Septal defects is the term for defects in formation of what 2 structures

septum primum and/or septum secundum

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What causes a probe patent foramen ovale and what type of shunting does it allow

caused by incomplete adhesion of the foramen ovale valve with the septum secundum

Left to right shunting

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What causes a patent foramen ovale and what type of shunting does it allow

Ostium secundum defects;
abnormal or excessive resorption of the septum primum or abnormal development of septum secundum

Left to right shunting

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What causes a patent foramen primum and what type of shunting does it allow

Ostium primum defects involving deficiencies in the endocardial cushion and atrioventricular septum formation

Failure of septum primum to fuse with endocardial cushions to fuse

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In what group is a patent foramen primum more common

those with Down syndrome

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What is the most common congenital heart defect

Ventricular septal defects

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Where do most VSD’s occur

defects in membranous portion of the interventricular septum

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What type of shunting do VSD’s allow and what can they cause

Left to right shunting of blood

Can result in pulmonary hypertension and possible cardiac failure

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What is the key defect in tricuspid atresia and what does it result in

complete occlusion of the right atrioventricular opening

results in cyanosis

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What defects always accompany tricuspid atresia

underdeveloped right ventricle and usually ASD and VSD

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What causes Persistant Truncus arteriosus

failure of the aorticopulmonary septum to develup and divide the truncus arteriosus into aorta and pulmonary trunk

What defect is always associated with Persistant Truncus arteriosus and why?

VSD because the membranous interventricular septum normaly merges with the aorticopulmonary septum

How does blood shunting occur with Persistant Truncus arteriosus

OVERALL RIGHT TO LEFT VSD thats present with it allows some left to right but Persistant Truncus arteriosus overwhelms it with right to left ( allowing blood to bypass the lungs)

How do you end up with transposition of the great arteries

when the aorticopulmonary septm fails to follow a spiral course when dividing the truncus arteriosus and bulbous cordus

What other defects are also usually associated with transposition of the great arteries

ASD and VSD and possibly patent ductus arteriosus

How does blood shunting occur with transposition of the great arteries

Overall Right to left ASD and VSD permit soome left right shuntin but most deoxy blood returning to right atrium bypasses the lungs and enters the aorta

What is the major cause of cyanotic heart disease in newborns

Transposition of the great arteries

What causes Tetralogy of Fallot

Unequal division of the bulbus cordis with anterior displacement of the aorticopulmonary septum

What 4 things result from tetralogy of Fallot

pulmonary stenosis overriding aorta VSD and hypertrophy of the right ventircle

What is the overall shunting in Tetralogy of Fallot

Right to left | of poorly oxygenated blood (thus cyanosis clinical sign)

What characterizes Coarctation of the aorta

constriction of varying length and usually occuriing directly opposite to the ductus arteriosus

What is Coarctation of the aorta typically associated with

Turners syndrome

When do you have Patent ductus arteriosus and what shunt does it cause

when the vessel fails to close and form ligamentum areriosum Left right shunt

In what cases is Patent Ductus areriosus commonly found

MATERNAL RUBELLA INFECTION DURING EARLY PREGNANCY Premature infants and those with persitent hypoxia

``` The fetal left atrium is primarily derived from coronary sinus endocardial cushion primitive atrium primitive pulmnoary vein sinus venosus ```

Primative pulmonary vein

``` Which of the following defects is associated with tetralogy of Fallot Aortic coarctation patent foramen ovale pulmnoary stenosis tricuspid atresia Patent foramen primum ```

Pulmnoary stenosis also see overriding aorta VSD and right ventricular hypertropy

What causes stenosis (narrowing) of the esophagus and where in the esophagus does it normally occur

incomplete recanalization of the lumen | usually occurs in distal third of esophagus

What 2 ways can atresia (closing) of the esophagus occur and which is more common

incomplete recanalization of the lumen or incomplete seperation of the trachea and esophagus 2nd is most common

What causes hypertrophic pyoric stenosis and what are the symptoms in an infant?

Thickening of the circular pyloric musculature (instead of incomplete recanalization) stomach markedly distended and infant has projectile vomiting

Where does stenosis of the duodenum usually occur

Horizontal (3rd) and ascending (4th)

Where does atresia of the duodenum almost always occur and sometimes occur?

Almost always in descending (2nd) | sometimes in horizontal (3rd)

Atresia arises in 1/3rd of individuals with what

Down syndrome

What symptom characterizes duoodenal obstruction

vomit containing bile

What causes Extrahepatic biliary atresia and where does it normally occur

incomplete recanalization of hepatic ducts | usually at or superior to porta hepatis

What symptom characterizes Extrahepatic biliary atresia

Infant develops jaundice soon after birth

What can cause an anular pancreas and what does it cause

bilobed ventral pancreatic bud grows and encircles the duodendum CAUSES OBSTRUCTION

What accounds for 50% of intestinal obstrections

stenosis and atresia of the ileum

What causes most ileal atresias

infarctions from twistin of the intestines

What is an omphalocele and what causes it

extrusion of abdominal viscera in the proximal umbilical cord caused by failure of intestines to normally return to abdominal cavity

What other defects is an Omphalocele associated with

Cardiac and neural tube defecs

How does an Omphalocele differ from an umbilical hernia

umbilical hernia, intestines return to abdominal cavity and then herniate through imperfectly closed umbilicus Omphalocele they never return to abdominal cavity

How does an omphalocele differ from gastroschisis

Visera in an ophalocele are covered ny peritoneum and the amnion derived covering of the umbilical cord

What causes most anomalies of the intestine

incomplete gut rotation

What are 3 types of improper gut rotation

Non rotation (cecum in middle small on left) mixed rotation ( small on left and middle colon transverse above and on right) reversed rotation (normal layout but duodenum in front of transverse colon)

Which two improper gut rotations is Volvus (twisting) of the intestines associated with and what can it result in

Nonrotation and mixed rotation | can result in gangrene of bowls

What is an ileal (Meckel) diverticulum and what can happen to it

Rmnant of the proximal part of the omphaloenteric duct can become inflamed and thus mimic symptoms of appendicitis

where is the ileal (Meckel) diverticulum attached and by what

can be connected to the umbilicus by an omphaloenteric fistula or a fibrous cord

What causes most anorectal anomalies

abnormal partitioning of the cloaca by the urorectal septum

What are 5 anorectal anomalies and which 2 usually present with fistula

``` imperforate anus anal agenesis (usually with fistula) anal stenosis anorectal agenesis (usually with fistula) rectal atresia ```

What makes up 2/3rds of anorectal defects

anorectal agenesis (with or without a fistula)

What is the most common cause of neonatal obstruction of the colon and what is it characterized by

Congenital megacolon (hirschsprung disease) characterized by abnormal dilation of the sigmoid colon and rectum

What causes the dilation in Congenital megacolon (hirschsprung disease)

neural crest cells fail to migrate into the hindgut and form parasympathetic ganglia in the gut wall

what is characteristic of the affected bowl and the bowl proximal to it in Congenital megacolon (hirschsprung disease)

affected bowl has absence of peristalsis proximal contains autonomic ganglia and consequently dilates

``` A 3 week old infant has a history of projectile vomiting. Vomit has no bile. Baby is constantly hungry but has not gained weight. Which explains the symptoms Esophageal atresia Ileal dierticulum Hypertrophic pyloric stenosis Tracheoesophageal fistula duodenal stenosis ```

Hypertrophic pyloric stenosis narrowing of pyloric canal and obstruction to passage of food blockage of duodeunum associated with vomit containing no bile

``` The embryonic midgut gives rise to which of the following duodenum liver sigmoid colon head of pancreas upper portion of anal canal ```

Duodenum

Clinical Embryology Flashcards

(69 cards)