Embryology of Lower GIT

Question 1

What separates the caudal end of the notochord from the cloacal membrane

Answer 1

Primitive node and primitive streak

Question 2

What does the diverticulum represent

Answer 2

Represents the forerunner to the development of the Urogenital sinus and Allantois

Question 3

What does the cloacal membrane consist of

Answer 3

Ectodermal endodermal bilaminar layers

Question 4

What layer surrounds the cloacal membrane

Answer 4

Mesoderm

Question 5

At the 3rd week the mesodermal layer differentiates into:

Answer 5

Para axial
Intermediate
Lateral plate

Question 6

When the lateral plate splits what is the result

Answer 6

Intra embryonic coelom

Question 7

Intra and extra embryonic coelom unite to form

Answer 7

Intra embryonic somatic mesoderm
Extra embryonic splanchnic mesoderm

Question 8

Cephalo-cordal and lateral folding of the embryo occur simultaneously; True or False

Answer 8

True

Question 9

What does the area of communication between the midgut section and yolk sac represent

Answer 9

Vitelline duct

Question 10

What suspends the gut from the posterior wall

Answer 10

Dorsal Mesentary

Question 11

Blood supply to the primitive gut are

Answer 11

Foregut- Celiac Trunk
Midgut- Superior Mesenteric Artery
Hindgut- Inferior Mesenteric Artery

Question 12

Hindgut comprises of

Answer 12

Distal 1/3 of transverse colon
Descending colon
Sigmoid colon
Rectum
Upper 1/3 of anal canal (pectineal line)

Question 13

What does the base of the vitelline duct develops into

Answer 13

Urinary bladder

Question 14

What does the endoderm lining give rise to:

Answer 14

Urothelial Epithelium-
Bladder
Urethra
Ureter
Renal pelvis and collecting duct tree

Question 15

What is the Allantois

Answer 15

Endodermal lined invagination of the yolk sac

Question 16

What starts to descend between the allantois and hindgut in the 3rd week

Answer 16

Urorectal septum

Question 17

What happens to the urorectal septum in the 7th week

Answer 17

Urorectal septum meets the cloacal membrane

Question 18

Perineal body:

Answer 18

The tip of the urorectal septum where it meets the cloacal membrane

Question 19

What forms anteriorly and dorsally to the Perineal body

Answer 19

Urogenital sinus (anteriorly)
Rectal Canal (dorsally)

Question 20

When the cloacal membrane is divided it forms:

Answer 20

Urogenital membrane (ventrally)
Anal membrane (dorsally)

Question 21

Which week is the Protoduem (anal pit) formed

Answer 21

8th

Question 22

What supplies the upper 2/3 of the anal canal

Answer 22

Inferior Mesenteric Artery (portal)

Question 23

Lower 1/3 of the anal canal is supplied by:

Answer 23

Inferior Rectal Artery

Question 24

Name the 3 parts of the urogenital sinus and what they form

Answer 24

Upper and largest part- Urinary ladder/ ureteric bud derivative
Pelvic Part- Prostatic and membranous urethra
Phallic part- Bulbar and penile urethra

Question 25

What is Imperforate anus

Answer 25

Anal canal ends blindly at anal membrane

Question 26

What is Rectal Atresia

Answer 26

Failure of the rectal ampulla to develop

Question 27

Urogenital membrane persist in females as the:

Answer 27

Vaginal Hymen

Question 28

Imperforate Hymen (female)

Answer 28

Persistence of an intact urogenital membrane

Question 29

Posterior Urethral Valve (male)

Answer 29

Persistence of remnants of the urogenital membrane