3. Development Of Gut

Question 1

Where does the midgut start and end in the human fully developed gut?

Answer 1

Midpoint of second part of duodenum - where common bile duct and pancreatic duct enter the duodenum
2/3 of the way along transverse colon

Question 2

What happens to the small intestines in the 6th week of development?

Answer 2

Intestines rapidly develop and an intestinal loop herniates through umbilical cord to gain space

Question 3

What is an omphalooele?

Answer 3

Gut is still in umbilical cord when born but still has peritoneal covering

Question 4

What is gastroschisis?

Answer 4

Failure of abdominal wall to form anteriorly
Lateral folding is incomplete so gut is herniated through umbilicus
Herniated contents not covered in peritoneum so exposed to amniotic fluid, negatively effects gut development

Question 5

What abnormalities can occur from the vitelline duct?

Answer 5

Vitelline cyst
Vitelline fistula
Meckels diverticulum

Question 6

What does the hindgut consist of?

Answer 6

Distal 1/3 transverse colon
Descending colon
IgM oil colon
Rectum
Superior anal canal
Bladder epithelia

Question 7

How is the cloaca divided?

Answer 7

Wedge of mesoderm descends and divides it into urogenital sinus and posterior anorectal canal

Question 8

When is the cloaca divided?

Answer 8

4-7th week

Question 9

What is the pectinate line?

Answer 9

In anus, where endoderm (columnar epithelia) meets the ectoderm (stratified squamous)

Question 10

What are some hindgut abnormalities?

Answer 10

Imperforate anus
Anorectal agenisis
Fistula (connection between rectum and bladder/vagina)