Embryo

Question 1

What are the 4 signs of Tetralogy of Fallot?

Answer 1

PROV

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

Question 2

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

Answer 2

Marked cyanosis

Question 3

What is the adult remnant of the left umbilical vein?

Answer 3

Ligamentum teres (“round ligament,” near liver)

Question 4

What is the adult remnant of the ductus venosus?

Answer 4

Ligamentum venosum (near liver)

Question 5

What is the adult remnant of the ductus arteriosus?

Answer 5

Ligamentum arteriosum (b/w aorta and pulm trunk)

Question 6

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

Answer 6

3rd letter in alphabet = “C”

- Right and left both develop into common carotid and beginning of internal carotid aa.

Question 7

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

Answer 7

• Right: right subclavian a.

- Left: aortic arch

Question 8

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

Answer 8

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

Question 9

Explain the basic rotation of the midgut.

Answer 9

Rotates 270 degrees counterclockwise

Question 10

What is physiological herniation?

Answer 10

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

Question 11

When does physiological herniation begin and end?

Answer 11

6th-10th weeks of devo

Question 12

What is Meckel’s diverticulum (generally)?

What is it a remnant of?

Answer 12

• Slight bulge in the small intestine

- A remnant of the vitalline duct (AKA yolk stalk–joins yolk sac to midgut lumen)

Question 13

Why is Meckel’s diverticulum referred to as a “syndrome of 2’s?”

Answer 13

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

Question 14

What is omophalocele?

Answer 14

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

Question 15

Of which gut is the cloaca?

What type of tissue is it?

Answer 15

• Hindgut

- Endoderm (as any gut tube is)

Question 16

What does the cloaca do?

Answer 16

• Receives the allantois

Question 17

What divides the cloaca and what is it divided into?

Answer 17

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

Question 18

What part of the urinary bladder isn’t endoderm?

What type of fetal tissue is it? Why?

Answer 18

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

Question 19

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

Answer 19

• Male

- Female

Question 20

How is the bladder related to the median umbilical ligament?

Answer 20

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

Question 21

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

Answer 21

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

Question 22

What is the allantois?

Answer 22

A small, endoderm-lined diverticulum off the hindgut

- Helps embryo exchange gases and handle liquid waste

Question 23

What is the yolk sac?

What gut is it connected to, and how is it connected to that gut?

Answer 23

• 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

Question 24

What is the urachus?

Answer 24

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