x exam 2 digestive system development II Flashcards
Foregut cranial most
pharyngeal pouches
derivatives of pharyngeal pouches are
endodermal structurees
1st pharyngeal pouch region/derivative
tympanic cavity and autitory tube
2nd pharyngeal pouch region/derivative
palatine tonsil
3rd pharyngeal pouch region/derivative
thymus; external parathyroid
4th pharyngeal pouch
internal parathyroid
6th pharyngeal pouch
C cells (parafollicular) of thyroid
salivary glands originate from what layers
endoderm combined with ectoderm (primitive gut tube)
salivary glands come from what pharyngeal structures
1st pharyngeal pouch + 1st pharyngeal celft
parotid salivary gland is from
invagination between maxillary and mandibular processes
manidbular and sublingual glands
evagination floor of oral cavity (mandibular processes)
esophagus lengthens as ____ forms
heaert and lungs
____ develops a junction of esophagus and pharynx
respiratory diverticulum
respiratory diverticulum forms the
lung bud; respiratory primordium; respiratory system
esophagus is ______ and lung bud is ____
dorsal; ventral
cranial esophagus is not enveloped by
intraembryonic coelom
cranial esophagus ends up in
mediastinum
simple stomach is formed from
fusiform enlargement caudal to septum transversum
simple stomach is initially _____
symmetrial
dorsal wall grows ____ and forms the ____
faster; greater curvature
ventral wall grows ____ and forms the _____
slower; lesser curvature
simple stomach rotates on _____
2 axes
craniocaudal (long) axis rotates
90 degrees clockwise
left becomes
ventral
drosal (greater curvature) becomes
left
dorsoventral (short) axis rotates
90 degrees
dorsal (greater curvature) becomes
caudal
pylorus becomes
right
esophagus/fundus becomes
left
coelom forms as a split in
lateral plate mesoderm
coelom was on left and right even in region to be
peritoneal cavity
conecting mesentary begins both
dorsally and ventrally
what happens to dorsal mesentary
persists
what happens to most ventral mesentary
degenerates almost immediatley
what parts of the ventral mesentary persist
umbilical v. and aa.
stomach is suspended by
dorsal and venral mesogastrium
dorsal mesogastrium becomes the
greater omentum
dorsal mesogastrium attaches to
dorsal body wall to greater curvature
dorsal mesogastrium pulled ____
caudally and left during rotations of stomach
dorsal mesogastrium expands greatly in
fetal period (greater omentum)
dorsal mesogastrium folds on itself and creates
omental bursa
what develops within the omental bursa
spleen; entirely mesodermal
ventral mesogastrium goes from
lesser curvature to liver and duodenum
ventral mesogastrium becomes
lesser omentum
ventral mesogastrium continues to
ventral body wall from liver as as falciform lig
ruminant stomach is initially like
monogastric
ruminant stomach differential growth into
greater and lesser curvatures
ruminant stomach rotates
craniocaudal and dorsoventral axes
cranial and left expands greatly to become
rumen and reticulum
evagination of lesser curvature becomes
omasum
abomasum continues to
right
rumen rotates _____
dorsocaudally
blind end of rumen
caudal and left median plane
sets location of other parts of stomach and other
abdominal organs
at birth, capacity of abomasum is ____ other compartments
two times larger than
postnatal changes are induced by
diet
nursing/liquids in the first several weeks
rumen, reticulum, omasum have no role in digestion
gastric groove: milk passes from esophagus to abomasum; allows milk to bypass rumen, reticulum, omasum
at 3 months
abomasum half size of rumen-reticulum
at 4 months
abomasum 1/4 size of rumen-reticulum
as an adult
abomasum is 1/10 size of rumen-reticulum
rumen-reticulum is ____ of stomach capacity
90%
hepatic diverticulum is an outgrowth of the
foregut; grows ventrally and cranially
hepatic diverticulum composed of
endoderm and splanchnic mesoderm
grows into _______
septum transversum; some connective tissue and blood vessels
growth of hepatic diverticulum surrounds
vitelline venous system; hepatic portal system and heaptic sinusoids
hepatic diverticulum ___ subdivisions
2
original diverticulum becomes
common bile duct
pars hepatica
liver
pars hepatica composed of
hepatocytes
heptaic biliary ducts (lumen of primitive gut tube)
pars hepatica within
ventral mesentary (lesser omentum; falciform ligamenta nd umbilical vein)
pars cystica becomes
gall bladder and cystic duct
what species lack a gallbladder
equine, rats
pars cystica atrophies
pancreas is formed from
2 diverticula of foregut; endoderm and splanchnic mesoderm
dorsal pancreatic diverticulum forms
accessory pancreatic
dorsal pancreatic diverticulum
lumen continued with foregut; duodenum at minor duodenal papilla
left lobe and accessory pancreatic
ventral pancreatic diverticulum
pancreatic duct and right lobe
lumen continued with foregut; duodenum at major duodenal papilla
dorsal diverticulum becomes
left lobe of pancreas
ventral diverticulum becomes
right lobe
fuse at contact point
body
duct systems of each diverticulum ____
interconnect
species variation
persistence or not of terminal portion that connects duodenum
canine pancreatic duct
minor, may be absent
canine accessory pancreatic duct
major
feline pancreatic duct
major
feline accessory pancreatic duct
usually absent
equine pancreatic duct
major
equine accessory pancreatic duct
usually absent
bovine pancreatic duct
absent
bovine accessory pancreatic duct
major
caprine pancreatic duct
major
caprine accessory pancreatic duct
absent
ovine pancreatic duct
major
ovine accessory pancreatic duct
absent
swine pancreatic duct
present
swine accessory pancreatic duct
present
endodermal cell derivatives: maintain connection to duct system
acini (secretory enzymes)
endodermal cell derivatives: lose connection to duct system
islets (endocrine)
midgut is the
primary intestinal loop
_____ defines axis of primary intestinal loop
cranial mesenteric artery
descending (cranial) limb
duodenum (part), jejunum and ileum (part)
ascending (caudal) limb
ileum (part) ascending and transverse colon
cecum is advierticulum of
ascending portion
yolk stalk connects on
ventral curvature of apex of loop
physiologic umbilical hernia
primary intestinal loop extends; outgrowht of abdominal cavity into extraembryonic coelom; surrounded by wall of umbilica cord- covered by amnion;
majority of physiologic umbilical hernia is
jejunum
normal transient herniation occurs at
week 4 of gestation
midgut rotation relationship with
root of mesentary
midgut rotates total of
270 degrees
1st 90 degrees during
physiologic umbilica herniation; cranial to right
next 180 degress during
retraction; developing large intestine settles in arch around perimeter of abdominal cavity (descending colon on left)
midgut continues rotation around
cranial mesenteric artery
positions transverse colon passes
right to left cranial to cranial mesenteric artery
expansion of ascending colon and cecum after
physiologic hernia resolved
ruminant and porcine
cecum enlarges
ascending colon expanded loop coils on itself = spiral colon
centripetal =
oral;
centrifugal
aboral
coil initially a ____ shape
cone; maintained in porcine
equine
cecum enlarges
ascending colon expanded loop folds= dorsal and ventral colons
apex of loop
pelvic flexure
fold point =
dorsal and ventral diaphragmatic flexures
cecum is a diverticulum of
fetal ascending colon
_______ maintain this relationship
carnivores
ingest flow
ileum to ascending colon via ileocolic orifice
ascending colon to cecum to ascending colon via cecocolic orifice
ascending colon to right colic flexure to transverse colon
species with expansion of cecum and ascending colon: initial fetal ascending colon recieves
ileum incorporated into the cecum
ingesta flow
ileum to cecum to ascending colon
hindgut derivatives
aboral (distal) transverse colon
descending colon
cloaca
allantois (evagination from cloaca; extends through umblicus and enlarges into extraembryonic coelom)
distal end of primitive hindgut expands to become
cloaca
cloaca is partitioned by
urorectal septum or fold
dorsal
anorectal canal
ventral
urogenital sinus (connected to allantois)
anorectal canal becomes
rectum and part of anal canal
urorectal septum grow
caudally fuses with cloacal membrane
dorsal part of cloacal membrane
anal membrane
ventral part of cloacal membrane
urogenital membrane
surface covering area becomes
perineum
anal canal centered at
anal membrane
cranial to anal membrane
endoderm lined
caudal to anal membrane
ectoderm lined
membrane degenrates
patent anal canal
urogenital sinus
keeps connection to allantois
region of cranial urogenital sinus and initial allantois becomes
urinary bladder
part of allantois from apex of urinary bladder to umbilicus
urachus
part of allantois passing in umbilical cord
allanatoic stalk
part of allantois expanding into extraembronic coelom is
allantois
mesentary of urogenital sinus dorsal
lateral ligament of urinary baldder (umbilical artery)
mesentary of urogential sinus ventral
median ligament of urinary bladder; (umbilica aa and urachus)
after birth, dorsal lateral ligament of urinary bladder
persists
umbilical artery becomes
round ligament of urinary bladders
after birth, ventral median ligament of urinary bladder
persists
umbilical artery
degenerates
urachus
degenerates