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Flashcards in Embryo Deck (24)
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What are the 4 signs of Tetralogy of Fallot?

- Pulmonary stenosis
- Right ventricular hypertrophy
- Overriding aorta
- Ventricular septal defect


What would be a symptom that is suspicious for Tetralogy of Fallot?

Marked cyanosis


What is the adult remnant of the left umbilical vein?

Ligamentum teres ("round ligament," near liver)


What is the adult remnant of the ductus venosus?

Ligamentum venosum (near liver)


What is the adult remnant of the ductus arteriosus?

Ligamentum arteriosum (b/w aorta and pulm trunk)


What does the right 3rd aorta arch develop into? Left?

3rd letter in alphabet = "C"
- Right and left both develop into common carotid and beginning of internal carotid aa.


What does the right 4th aorta arch develop into? Left?

- Right: right subclavian a.
- Left: aortic arch


What does the right 6th aorta arch develop into? Left?

- Right: obliterated or possibly right pulmonary a. (won't be tested)
- Left: ductus arteriosus and left pulmonary a.


Explain the basic rotation of the midgut.

Rotates 270 degrees counterclockwise


What is physiological herniation?

As the midgut grows during its development, most of it leaves the body in a sac


When does physiological herniation begin and end?

6th-10th weeks of devo


What is Meckel's diverticulum (generally)?
What is it a remnant of?

- Slight bulge in the small intestine
- A remnant of the vitalline duct (AKA yolk stalk--joins yolk sac to midgut lumen)


Why is Meckel's diverticulum referred to as a "syndrome of 2's?"

7 reasons:
- 2 ft. from ileocecal valve
- 2" long
- 2% of population has it
- 2% of them are symptomatic
- 2 types of ectopic tissue (gastric + pancreatic)
- 2 year age at clinical presentation
- 2x more common in boys


What is omophalocele?

Failure to return the abdominal intestines to the abdominal cavity (s/p physiological herniation)


Of which gut is the cloaca?
What type of tissue is it?

- Hindgut
- Endoderm (as any gut tube is)


What does the cloaca do?

- Receives the allantois


What divides the cloaca and what is it divided into?

- Urorectal septum divides it into
1. Urogenital sinus
2. Anal canal


What part of the urinary bladder isn't endoderm?
What type of fetal tissue is it? Why?

Trigone (mesoderm, cuz it's connected to the brain)


The mesonephric duct is (male or female?), and the paramesonephric duct is (male or female?).

- Male
- Female


How is the bladder related to the median umbilical ligament?

Bladder is continuous w/the allantois -> urachus -> median umbilical ligament


As the bladder enlarges, what happens to the mesonephric ducts?

The distal parts of the mesonephric ducts are encorporated into the dorsal wall (trigone)


What is the allantois?

A small, endoderm-lined diverticulum off the hindgut
- Helps embryo exchange gases and handle liquid waste


What is the yolk sac?
What gut is it connected to, and how is it connected to that gut?

- A ventrally endoderm-lined structure
- Connected to the midgut by vitelline duct

- Important for fetal blood supply, and will be incorporated into gut by 4th week


What is the urachus?

Connects fetal bladder to the yolk sac (removes nitrogenous wastes from the fetal bladder)