Development of midgut and hindgut Flashcards
At ——- week the midgut consist of simple loop suspended and supplied by —————– in the —————-mesentery
5th - superior mesenteric - dorsal
Midgut communicate with yolk sac through ————-
Vitelline duct
midgut simple loop swelling in the caudal limb marks the future ——————–
caecum
midgut derivative : The cranial limb elongates greatly
to form the ———– and two-thirds
of the ————
jejunum-ileum
The proximal part of the
vitelline duct persists in 2%
of individuals as —————————
Meckel’s
diverticulum
the caudal limb of midgut will form ————-,————,—————-,—————,————-
Distal end of ileum- Cecum - appendix - ascending colon- Rt 2/3 of Transverse colon
Midgut Herniation =
At ———- week the midgut loop
elongates rapidly and the———
enlarges. The abdominal cavity
becomes relatively ——— and part of
the intestine herniates into the
——————, through the coelomic opening next to the umbilical cord.
6
liver
small
extra-embryonic coelom
Midgut Retraction
During the ————- week the abdomen enlarges
and the intestine returns into the abdominal
cavity. As this occurs, the midgut loop ———-
so that the different parts of the intestine
acquire their definitive positions in the
abdominal cavity
10th
rotates
How many positions of Caecum during development ?
3
Midgut Rotation - The caecum in the caudal limb of the midgut, the loop is taken landmark for rotation. - It rotates through a total of---------------- to acquire its definitive position. The rotation occurs in ------- stages: a. At ----- week: -------- anticlockwise - the caecum is shifted to the ----------- b. At -------- week: --------------- - the caecum acquires its definitive position Three positions of the caecum during midgut development
270° anticlockwise-two-6th-90°-left-10th-180° anticlockwise
Caecum situated caudally
————week
Caecum below a
the ————-lobe of liver Caecum in right
———–week
Caecum in the right iliac fossa—– week
6th -right -10th-11
Congenital anomalies
——————-Clockwise rotation results in intestinal situs inversus
- Failure of rotation may result in left-sided caecum
appendix and ascending colon
- Incomplete rotation - subhepatic caecum and appendix )
Malrotation of the gut
Congenital anomalies
————– is a rotation of an intestinal loop around is
a branch of the superior mesenteric artery - it may
cause intestinal obstruction or even gangrene
Volvulus
Congenital anomalies
——————— is the invagination of a segment of intestine it self
causing obstruction
Intussusception
- Persistent Vitello-intestinal Duct and
Meckel’s Diverticulum
There are various degrees of persistence of vitelline
duct:
- ————— - meconium oozes out of umbilicus
- ————— - part of duct is not obliterated
- ————— - attaches ileum to umbilicus
- ————— - persistent proximal part of
vitelline duct occurs in 2% of normal individuals
Vitelline fistula
Vitelline cyst
Vitelline cord
Meckel’s diverticulum
Gastroschisis - Herniation of viscera through --------------------------------- into the amniotic cavity - to the-----------------of the umbilicus * no covering membranes; viscera bathed directly in amniotic fluid. - ------------ commonly associated with other anomalies
ruptured abdominal wall defect
right
less
Omphalocele - Herniation of abdominal viscera through a --------------------- - defect of ---------------- mesoderm - Viscera covered by ----------and --------------------- - 50% have other serious congenital or chromosome abnormalities
large umbilical ring
lateral plate
peritoneal +amniotic membrane
The Hindgut --------- days: After formation of the tail fold, the allantois and hind gut open (into a common chamber the cloaca. The cloacal membrane separates --------- from the ---------- The allantois appears at about---------- days small diverticulum projecting _ from the caudal end of the yolk sac into the connecting stalk . The ----------------septum separates the hindgut from the allantois. It grows towards the cloacal membrane. It is derived from --------------at the junction between the connecting stalk and yolk sac.
26-cloaca-proctodeum.
16
urorectal
mesoderm
The urorectal septum separates the ------- from the ----------. It grows towards the cloacal membrane. It is derived from ----------at the junction between the connecting stalk and yolk sac.
hindgut-allantois
mesoderm
The urorectal septum grows towards the -------------- but does not fuse with it. It is derived from ---------- at the junction between the connecting stalk and yolk sac.
cloacal membrane-mesoderm
During the ———-week the cloacal
membrane disappears, exposing a
ventral ————– opening
and a ———–.
7th -urogenital sinus-dorsal anal opening
The tip of the urorectal septum, Separating
the two openings forms the ———-body.
perineal
The Anal Canal -At the end of the ---------- week, after rupture of the cloacal membrane, proliferation of ------ occludes the anal opening
8th-ectoderm
During the———— week the opening is
recanalized
9th
Thus the terminal part of the anal
canal is ———— in origin and is
supplied by the ———–
ectodermal-inferior rectal artery
The junction between ectoderm and
endoderm is the ————-.
pectinate line
Congenital anomalies of large intestine
Aganglionic Megacolon - Hirschsprung Disease
Due to congenital absence of ————–
ganglia in the colon. This is a ——— migration defect.
It varies in extent -
80% involve —– and ———
3% involve the whole colon.
parasympathetic
neural crest
sigmoid colon
rectum:
Imperforate anus
baby has an improperly developed anus, and therefore can t pass ———- normally from his rectum out of the body.
Stool
ينزل بول و بطنه تكون منتفخة
lower part of anal canal arise from —————(———-)
Proctodeum ( Ectoderm)
During week ———-anal membrane ruptures and anal canal open in tail region (osmosis)
7th
